AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Week 6 - equipment 3 |
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1. Why is it often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface?
Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
4. What information is stored in the session file?
5. Are session files usually transportable between different systems?
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
6. What is 'fragmentation'?
7. Comment on archiving to CD-ROM.
8. What are 'virtual tracks'?
9. What is meant by 'edit density'? What are the implications of high edit density?
10. Does the editing and trimming of regions delete audio data from the disk?
11. In editing, what is the difference between 'slip' and 'grid' modes?
12. When might it not be possible to create a crossfade?
13. What is 'bouncing', in the context of mixing?
14. What is meant by 'latency'?
15. What is the difference between DSP processing and host-based processing?
16. Was DAT originally intended as a professional or a domestic recording medium?
17. What is the sampling rate of standard DAT?
18. What is the resolution of standard DAT?
19. What is 'azimuth recording'?
20. Describe the head wheel in DAT recorder.
21. What is SCMS?
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
23. What is the sub-code area of the DAT tape used for?
24. What is 'interleaving'?
25. What is the width of the tape used for 24-track DASH?
26. What is the width of the tape used for 48-track DASH?
27. Describe how 24-track and 48-track DASH machines are compatible.
28. How are DASH tapes edited?
29. In DASH, why does a playback head come before the record head in the tape path?
30. Comment on the cleaning requirements of DASH
31. How many tracks does a modular digital multitrack (MDM) have?
32. How can more tracks be obtained?
33. Comment on the types of usage of ADAT and DTRS machines?
_________________
It's all in the ears. - Learn the concepts not the software.
Audio Courses is a way into the music business for you
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Mon Apr 11, 2005 6:35 am |
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JohnA
Joined: 20 Jan 2005
Posts: 28
Location: Mid Glamorgan, UK |
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Audio Course
AURT03
Week 6
Equipment 3
JohnA (mixindown)
1. Why is it often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface?
Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
An integrated disk recording system is a system that is built for the job. If you encounter any technical problems, you can contact the manufacturer who will know the product inside out and be able to help with any solutions. This is important in a pro set up where artists have booked studio time. Personal computers are far more difficult to run because there are many factors that can hinder solving problems that can arise. Incompatability with sound cards / sequencing packages / drivers etc makes an integrated disk recording system more attractive.
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
A tape recorder with 24 inputs and 24 outputs will have 24 tracks. To be a replacement for a 24 track tape recorder, a tape recorder with 2 inputs and 2 outputs could suffice.
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
It’s main limitations would be that you could only record a maximum of two tracks at a time so you could not, of example, record a miked up drum kit with say, seven microphones, in one go. Another limitation would be that, if you only have two outputs and you had 24 tracks recorded, you would be unable to route a large number of separate tracks out for processing separately in a mixing desk.
4. What information is stored in the session file?
Information that is stored in a session file includes the project title, which audio and midi files were used and where they are stored, information on all editing executed, plug in information, mixer settings,
5. Are session files usually transportable between different systems?
Session files are not “usually” transportable between different systems. However, if two systems contain the same hardware and software profile, sessions can be transferred.
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
SCSI (Small Computer System Interface) is a parallel interface standard (a channel capable of transferring more than one bit simultaneously). SCSI has been widely used for audio recording because it has a fast data transmission rate (up to 160Mbps) which is faster than standard serial and parallel ports. It is easy to transfer data from one computer to another via a cable. It’s reliable. You can also connect up to 15 other SCSI devices to one unit all run from a single IRQ required by its adaptor card. However, if your computer is not set up for SCSi, you will have to install and configure a host adaptor card.
ATA (originally know as IDE: Integrated Drive Electronics). A hard disk with the disk controller integrated with it. Unlike SCSI, the controllers are on each drive so the drive can connect directly to the motherboard or controller. Overall, cheaper and easier to set up than SCSI but only allows two devices per channel. Available in 7200 and 10,000rpm speeds (fast spindle speed in vital for continuous recording).
FIREWIRE: (IEEE 1394). Supports Isochronous data ensuring that the audio is delivered at a guaranteed rate (important for streaming audio in real time). Also supports hot plugging/swapping. Firewire IEEE 1934a supports transfer rates of up to 400Mbps and IEEE 1934b supports 800Mbps (backwards compatible). Supports up to 63 devices connected on a single bus.
6. What is 'fragmentation'?
Fragmentation is when a files is scattered around different areas of a hard disk instead of being in one contiguous area. This makes the information slower to read.
7. Comment on archiving to CD-ROM.
It is important to back up your audio / midi files. Hard disks are mechanical and therefore, it is inevitable that one day, they will stop working. Backing up onto CD-ROM ensures that, in the event of a failure of your hard drive, you will be able to import your original files for use to remix, copy etc. One of the big advantages of storing your files on CD ROM is that CD_ROM’s cannot be written over (not like CD RW). Therefore, once you have stored your information, its there forever (well, around 100 years if you store it correctly). When copying files to CD ROM, its advisable to make at least two copies and store both these at different locations in case of accidents. If it hasn’t been backed up at least twice, it isn’t backed up!
8. What are 'virtual tracks'?
A virtual track is the computer equivalent of a track taped on a multi-track tape recorder. This could apply to midi virtual tracks and audio virtual tracks.
9. What is meant by 'edit density'? What are the implications of high edit density?
High Density is when data is tightly packed on a disk. When an audio track is recorded in one go, the audio is stored on a section of the hard disk. If it is played back as one continuous file, the computer and software has no problem reading it. However, if this file is edited with the sequencer, the computer now has to search different areas of the hard drive for the various edits. This makes it difficult for the computer to play a number of tracks back at the same time whose regions are in various places on the hard disk drive. If the tracks have had a lot of editing applied to them, they are said to have a “high edit density”. The potential problem caused by high edit density is that fewer tracks could be played simultaneously.
10. Does the editing and trimming of regions delete audio data from the disk?
No. The regions are just visuals for you to see sections of the track. If you were to record a 1 minute guitar solo, then cut it in half and use just the first 30 seconds, the sequencer would play just the 30 seconds you have on the screen. This region tells the software to play the first 30 seconds of that track from the full 1 minute that is stored on disk.
11. In editing, what is the difference between 'slip' and 'grid' modes?
When you move files in your sequencing package in grid mode, the files are snapped to an onscreen grid, to settings that the user has defined. This can make for very accurate editing when quantising for timing purposes.
Slip mode, frees up the restrictions of grid mode, enabling you to move a file to any location on the sequencing screen. This can be a good mode to comp vocals in and can stop the timing of the vocal from sounding too rigid.
12. When might it not be possible to create a crossfade?
Crossfades are performed between regions of overlapping audio so a crossfade cannot be performed on regions that do not contain any audio material beyond their region boundaries.
13. What is 'bouncing', in the context of mixing?
Bouncing is mixing down a number of previously recorded tracks onto an available blank track. Once the bounce has been done, the tracks from which you originally bounced, can be cleared, allowing for new audio to be recorded on them.
14. What is meant by 'latency'?
Latency is a measure of how long, on average, it take to get a response from something. When playing a software synth with a keyboard controller through a computer and into an amp with speakers, it would be how long it took for you to hear the signal from pressing the key on the controller.
15. What is the difference between DSP processing and host-based processing?
DSP (Digital Signal Processing) is performed by a dedicated processor. This is usually on a separate board, such as a sound card. Host based processing requires the computers processor to carry out the processing functions.
16. Was DAT originally intended as a professional or a domestic recording medium?
It was originally meant for domestic use as a replacement for compact cassette tapes.
17. What is the sampling rate of standard DAT?
44.1kHz
18. What is the resolution of standard DAT?
16 bit.
19. What is 'azimuth recording'?
The azimuth is a reference to the angle between where the recording takes place (the head gap) and the tape track itself. In analogue recording, the azimuth is adjusted to 90 degrees. In DAT recording, there are two heads, one is set at –20 degrees and the other set to +20 degrees to the tape. Each of these lays down tracks alternatively. When the tracks are played back, each track receives a strong signal from the track that it recorded. The adjacent track is misaligned by 40 degrees to it so the signal is so weak, it can be totally rejected. This eliminates crosstalk.
20. Describe the head wheel in DAT recorder.
DAT uses a minimum of two magnetic heads that are mounted inside a drum dedicated rotary drum. This is just 30mm in diameter. This drum spins at 2000rpm). The actual tape is only wrapped a quarter of the way around the head. This means that, at times, neither of the two heads is in contact with the tape. Because the tape is only wrapped around the head at 90 degrees, there is only a short length of tape in contact with the drum at any given moment. This means that you can search the tape at high speeds because the tension of the tape is low. This also prolongs the life of the tape.
21. What is SCMS?
SCSM (Serial Copy Management System). This is on consumer level DAT systems. The SCSM system will allow you to make a copy of the recording onto a DAT tape but will not allow you to make a “copy from the copy”. This can also apply to CD-R’s.
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
If an extra pair of heads is mounted on the drum of the DAT recorder, simultaneous off-tape monitoring can be performed during recording just like a three-head analogue tape recorder.
23. What is the sub-code area of the DAT tape used for?
Of more interest to the actual use of DAT are the Sub Code areas of the track. These Sub Code areas allow extra data to be recorded alongside the audio information. Not all of the capacity of the Sub Code areas is in use as yet, allowing for extra expansion of the DAT system. Those at present in use include: time codes (not SMPTE/EBU timecode, apart from the professional Fostex D20 machine). These can log the total elapsed time and the time since the beginning of each item on the tape; the Start ID marks the beginning of each item; the Skip ID tells the machine to go directly to the next Start ID, thus performing an ‘instant edit’. These codes make DAT easier to use.
24. What is 'interleaving'?
Interleaving is an extra precaution against drop-outs. This scatters the data on a DAT so that if one section of data is lost, then there will be enough data elsewhere - hopefully beyond the site of any tape damage - which can be used to reconstruct the original signal.
25. What is the width of the tape used for 24-track DASH?
½” open reel tape.
26. What is the width of the tape used for 48-track DASH?
Also ½” open reel tape.
27. Describe how 24-track and 48-track DASH machines are compatible.
DASH (Digital Audio Stationary Head) format had always left space on the tape for 48 tracks, half of the tape is blank for the 24-track version. A 24-track tape will play on a 48-track machine, and the first 24 tracks of a 48-track tape will play on a 24-track machine.
28. How are DASH tapes edited?
It is possible to allow cut and splice editing in DASH but it is unreliable. DASH tapes can be better edited by copying the tape to another machine. By utilising a specialized controller, you can copy a segment of audio from one machine to another. Then you can set an 'offset' between the two machines so that when the record machine comes to the end of your first segment, the other machine is just about to start playing the next segment of audio you want to edit on. You can set the punch-in to record to occur automatically.
29. In DASH, why does a playback head come before the record head in the tape path?
Unlike the simultanious record and playback of analogue recording systems, when you playback on a DASH system, there is a slight delay while the signal has had time to be processed. Because of this delay, the record head needs to come after the playback head. This is another reason why overdubbing is difficult.
30. Comment on the cleaning requirements of DASH
The heads can be cleaned with a special chamois leather tool. Cotton buds that are used for analogue records will clog the DASH head
31. How many tracks does a modular digital multitrack (MDM) have?
There are 8-tracks on an MDM (Modular Digital Multi-track).
32. How can more tracks be obtained?
You would need to purchase extra machines to increase the track count.
33. Comment on the types of usage of ADAT and DTRS machines?
ADAT and DTRS machines are both refered to as MDM’s. ADAT (Alesis Digital Audio Tape) machines are usually used in either home recording setups or recording studio setups, and has become the most widely used professional digital recording system. Its transportability makes it an ideal choice for location recording. Two or more systems can be connected via lightpipe cables which are much thinner and lighter than standard balanced/unbalanced cable and therefore easier to manage. ADAT has been readily adopted my many other manufacturers which now makes the transfer of data between ADAT systems much broader. Tascam DTRS (Digital Tape Recording System) machines are usually found used in broadcasting and post-production situations and can provide up to 108 minutes of 16 bit recording.
http://www.soundonsound.com/sos/Jun02/articles/pronotes0602.asp
http://audiotools.com/dat.html
http://www.soundonsound.com/sos/Jun02/articles/pronotes0602.asp
http://www.soundonsound.com/sos/jul99/articles/cdrmastering.htm
http://www.rogernichols.com/EQ/EQ_2001_09.html
http://www.jrn.columbia.edu/studentwork/radio/help/newsession.asp
http://www.prosoundweb.com/studyhall/bp/pt/edit4.php
http://www.soundonsound.com/sos/aug98/articles/digitalbasics.html
http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci213485,00.html
JohnA |
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Fri Apr 15, 2005 2:33 pm |
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hoaxwagon
Joined: 28 Feb 2005
Posts: 27
Location: Boulder Creek, CA USA |
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RT wk 6 Q&A
1. Why is it often considered better to use an integrated disk recording system rather than
one that uses a personal computer as the user interface?
An integrated disk recording system is portable, reliable, and easy to use. One manufacturer is who you
deal with for support or repair.
A PC interfaced disk recording system with its operating system limitations and numerous components
and systems by different manufacturers is more complicated. Compatibility issues with hardware and
drivers, software and OS’s and the probability of a system crash make this method less user friendly.
Comment on the presentation of some disk recorders as replacements for tape multitrack
recorders.
There are some disk recorders that offer mixing capabilities on-board and some that allow DSP as well
as host based processing. This combines the feel of a mixing console with the flexibility of effects
plug-ins. A replacement for tape multitrack recorders? I don’t think so. A coexisting viable technology
perhaps.
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
This tape recorder would have 24 tracks.
How many inputs and outputs would a disk recorder need if it was to be a replacement for a
24-track tape recorder?
A disk recorder would need to have 24 inputs and 24 outputs to be a replacement for a 24 track tape
recorder.
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four
tracks, what would be its main limitations?
If a 24 track disk recording system had two inputs it would be only able to record 2 tracks at a time.
The two outputs could be used for monitoring left and right channel stereo out.
4. What information is stored in the session file?
The name and date would be in there as well as audio files and a plug-in settings library perhaps.
5. Are session files usually transportable between different systems?
Yes if the systems are the same with the same plug ins available.
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
FireWire is serial, as opposed to parallel tasking like SCSI, so data transfers over FireWire may take
more CPU cycles to accomplish than when using SCSI. On older computers this can be a problem, but
not so much now that 3 gigahertz-speed processors are so affordable.
6. What is 'fragmentation'?
Fragmentation is when clusters of information are spread out all over the disk. Fragmentation occurs
naturally with everyday use. When files are deleted, a space is left behind and later filled with a similar
size files. This is eventually leads to scattered information and a slower running computer.
7. Comment on archiving to CD-ROM.
CD-ROM files can be encoded in virtually any bit depth and sample rate. The CD-ROM disk’s are
inexpensive and the technology is widely used.
8. What are 'virtual tracks'?
Virtual tracks are available on digital recorders. Each track would also have a set number of virtual
tracks that can be used for second, third or forth takes for comparison purposes or to make room for
another track to be recorded.
9. What is meant by 'edit density'?
What are the implications of high edit density?
Edit density is a term used when describing the amount of edit points per second occurring during
playback. High density, say like 2 edits per second, can result in halving the amount of tracks able for
playback.
10. Does the editing and trimming of regions delete audio data from the disk?
I believe as long as the undo feature is active, the last few trims are still on the disk and available for
recovery.
11. In editing, what is the difference between 'slip' and 'grid' modes?
These modes are found in Pro Tools.
"Slip" mode. This mode will allow you to move audio freely within your
session.
“Grid” mode is used well with drum beats because it keeps the regions in time on a user-set grid. This
grid can be set to 1/4 notes, 1/2 notes or by milli- seconds.
12. When might it not be possible to create a crossfade?
A crossfade between regions, without handles, that represent the entirety of an audio file may not be
possible.
13. What is 'bouncing', in the context of mixing?
Bouncing is when 2 or more tracks are combined on to another track. This is also an opportunity to lay
down a live take on the same track at the same time as the bouncing.
14. What is meant by 'latency'?
Latency is the delay time between a sound entering the sound card and the sound coming back out.
While using a computers operating system a signal is bound for latency. All systems suffer this problem.
15. What is the difference between DSP processing and host-based processing?
Host based processing involves a computer, tends to have higher latency and doesn’t use DSP chips.
16. Was DAT originally intended as a professional or a domestic recording medium?
Conceived by SONY to replace the domestic cassette market. It instead ended up catching on in the
professional market instead.
17. What is the sampling rate of standard DAT?
44.1 khz and 48 khz are standard sample rates as well as 32 khz in LP mode.
18. What is the resolution of standard DAT?
The resolution of a standard DAT is 16 bit.
19. What is 'azimuth recording'?
Azimuth recording is when there is a 40 degree error between the 2 heads in the head drum. This method
of recording minimizes cross-talk by reducing the amount of overlap between the heads respective data
on the tape.
20. Describe the head wheel in DAT recorder.
The head wheel (wheel drum) spins 2000 RPM in the same direction the tape is moving. As the tape
moves over the wheel drum the record heads inside lay down diagonally and slightly overlapping tracks
on the tape. The tape follows a spiraling guide on the drum called a rabbet
21. What is SCMS?
Serial copy management system is a means of controlling the amount of, if any, copies that can be made
using S/PDIF. The setting of ID6 of the subcode should determine this adjustment.
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape
recording?
23. What is the sub-code area of the DAT tape used for?
The sub-code area of the DAT tape is used to allow the user to write Erase, Start, Skip and End ID’s.
A channel coding structure called SCMS would also be recorded in the sub-code area.
24. What is 'interleaving'?
Interleaving is the arrangement of sectors on a track so they are work well with the speed of the disk
controller or head wheel.
25. What is the width of the tape used for 24-track DASH?
26. What is the width of the tape used for 48-track DASH?
Both 24 and 48 track DASH use 1/2 inch tape
27. Describe how 24-track and 48-track DASH machines are compatible.
DASH machines are considered backwards compatible, which means that they are compatible with one
another. If a recording is started on the 24 track and switched to 48 track machine, the tracks 25
through 48 are placed between the tracks already recorded by the 24 track machine.
28. How are DASH tapes edited?
DASH tapes can be edited with the use of a second machine or razor blade editing can be used with a
crossfade feature to make it seamless.
29. In DASH, why does a playback head come before the record head in the tape path?
Not sure but I think one reason why the playback head comes before the record head is to provide
alignment of the tape.
30. Comment on the cleaning requirements of DASH
Because of the error correction systems used in digital tape machines, there's usually very little warning
that something is wrong, so preventative maintenance is essential. After 500 hours, the machine should
be serviced by an professional. Cleaning on a regular basis the head wheel, heads, guides and brushes is
something you can do with a lint free silk like materiel and isopropyl alcohol. Cotton swabs fibers will
clog the head up therefor should not be used.
31. How many tracks does a modular digital multitrack (MDM) have?
A MDM has 8 tracks
32. How can more tracks be obtained?
More tracks can be obtained by linking more machines together
33. Comment on the types of usage of ADAT and DTRS machines?
These machines are still in use widely and have their advantages, since they may be linked easily to
provide large track counts and may dub with no signal degradation. Tapes may easily be cloned and
shared between studios, making collaborative work easy. They have proven very popular and are likely
to continue for some time even as hard-disk-based recording becomes increasingly desirable and
inexpensive. |
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Sat Apr 16, 2005 1:22 pm |
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Freshwayne
Joined: 28 Feb 2005
Posts: 5
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1. Why is it often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface?
The disk recorder's is dedicated to the recording and editing of the disk whereas with a computer, its resources are not
exclusively given over to the recording process - also there is a reliance on several differnent people to make the audio process happen - the computer manufacturer, the software company etc... whereas with a standalone system it is not the case - its dedicated.
Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
Would this be visually? Visually the disk recorders are made to look like their pre-decessors the tape recordors to make the transition between the two seemless, the buttons play etc... are virtually identical!
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
24 Tracks.
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
I would say 24 but this stinks of a trick question!!!
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations
?
You could only record two sound sources at a time - take an example of a drum kit where you may need up to 8 mics or something! Thats a disaster. As regards outputs again the limitation is that at best the recording system can only mix down to stereo.
4. What information is stored in the session file?
i) The Audio files/samples used ii) Edits made to these audio files iii) sample rates and bit resolution of the same
iv) Track assignments v) Plug in data vi) Mixing information
5. Are session files usually transportable between different systems?
I would imagine and be fairly certain no because of different software configuration etc..
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
SCSI is a very high speed (up to 80 MB/sec) parallel interface. This is ideal for audio recording. Unfortunately the price is quite high for SCSI
ATA drives are slower and indeed are cheaper but these can represent a slow data exchange which is undesireable for audio.
Firewire/IEEE 1394 is a fast external bus standard allowing for data transfer rates from 400 Mbits per second (IEEE 1394a) to 800 megabits per second (IEEE 1394b). Firewire also supports isochronous data transfer. This is ideal for transferring huge amounts of data - idea for audio recording.
6. What is 'fragmentation'?
Fragmentation is the breaking down of a large data file into smaller fragments across the surface of the hard disk drive used in recording.
7. Comment on archiving to CD-ROM.
Cheap archiving system,good software support available,can hold up to 80 mins at 44.1 kHz stereo signal to sixteen bits per channel. In terms of data it can hold 650 megs which is condsiderable.
8. What are 'virtual tracks'?
Virtual tracks are tracks in memory of a system assigned to a main track channel that it is possible to record multiple takes to, thus having several different takes to play around with then mixing down. It is worth noting that even though there may be for example only 8 actual tracks, each actual track can have for example 8 virtual tracks, so in effect there are 64 tracks to play around with and mix down to the actual tracks.
9. What is meant by 'edit density'? What are the implications of high edit density?
The edit density is the scattering of data when audio is edited across the hard drive. The more scattered, the greater the edit density and the more processor power required to playback and edit properly. High edit density can cause jumps / delays in playback and accessing data for editing.
10. Does the editing and trimming of regions delete audio data from the disk?
Only if the changes are saved. If not it just plays back the section with the edits in place. There will of course usually be an option to undo these changes.
11. In editing, what is the difference between 'slip' and 'grid' modes?
Slip mode - you can move an audio region to any location you want. Grid mode - you can move an audio region according to the grid lines (you cannot place region between grid lines)
12. When might it not be possible to create a crossfade?
If you are recording in a loop. To create a crossfade, the cross-fader takes a bit from the beginning and the end of a section. When you are in a loop at the very beginning or end of the sample there is no data to draw from. Also if there is no audio on one track it will not be possible.
13. What is 'bouncing', in the context of mixing?
This is the graphical explanation of bouncing tracks.
I will represent the tracks with the numbers 1-4. To represent that something is recorded on a track the color will be green. If a track contains bounced tracks, the number will be blue.
Blank Tracks
Recorded Tracks
Bounced Tracks
Start with 4 blank tracks
1 2 3 4
Record instruments/vocals etc. on 3 of the tracks
1 2 3
4
Listen to these three tracks and adjust them so they sound the way you want. Record the three tracks onto track 4. (How this is done may vary from one machine to the next. Most likely you'll need to select track 4 to be recorded on and the others should be in playback only)
1 2 3
4
(1,2,3)
Next, erase the three original recordings. Now you have three blank tracks on which to record. You're setup should now be like this:
1 2 3
4
(1,2,3)
14. What is meant by 'latency'?
Latency is the time a message takes to traverse a system. In the case of audio - an example may be if a keyboard is being monitored through a sequencer and a note is played, it may take time for the note to be actually heard through headphones/monitor because of the time it takes to travese the system. This delay is Latency.
15. What is the difference between DSP processing and host-based processing?
DSP stands for Digital Signal Processing. This is when the software is doing the processing. In host-based processing, the computer’s CPU does the processing.
16. Was DAT originally intended as a professional or a domestic recording medium?
DAT was introduced in 1987 for the professional studio market, digital audio tapes quickly claimed the high ground in professional recording industry circles. DAT's never garnered consumer market penetration because of the high cost of DAT players. However, they remained a mainstay of the pro-audio world because of their relatively low price and digital storage capabilities.
17. What is the sampling rate of standard DAT?
The standard sampling rate of DAT is 48000
18. What is the resolution of standard DAT
?
The resolution of standard DAT is 20bit, however some high end machines are 24bit resolution.
19. What is 'azimuth recording'?
Azimuth recording is a type of recording where the heads need to be absolutely vertical with respect to the tape (I think?).
20. Describe the head wheel in DAT recorder.
DAT systems use a headwheel that spins at 2,000 rpm , similar to that in a videocassette recorder. Various types of data can be recorded with the audio such as time code and the MIDI machine control data used in sophisticated postproduction audio work
21. What is SCMS?
SCMS stands for "Serial Code Management System" and is the way copies of digital music are regulated in the consumer market. It is information that is added to the stream of data that contains the music when one makes a digital copy (a "clone").
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
I honestly couldn't find anything on this anywhere.
23. What is the sub-code area of the DAT tape used for?
The subcode tracks contain the sample-rate clock, as well as the track IDs.
24. What is 'interleaving'?
Interleaving is used to scatter data around the DAT medium in such a way that if a large section is lost or damaged, when the data is reordered many smaller, manageable data losses are formed, which the detection and correction systems can hopefully deal with.
25. What is the width of the tape used for 24-track DASH?
Quarter inch open reel tape.
26. What is the width of the tape used for 48-track DASH?
Half inch open reel tape.
27. Describe how 24-track and 48-track DASH machines are compatible.
Dash machines are what is known as 'Backward Compatible', in other words the tapes can be transferred between the two. A 48 track tape when placed on a 24 track machine will play tracks 1 - 24 only, and a 24 track tape placed on a 48 track machine will play tracks 1-24 and still be able to record tracks 25 - 48.
28. How are DASH tapes edited?
The more old fashioned way of editing is to actually cut and splice the tape together, however it is currently more desireable to play the tape onto another recorder and edit it together that way.
29. In DASH, why does a playback head come before the record head in the tape path?
I think that it is because in the case of the DASH machines there is a delay between the tape passing the head and the signal being passed through the recorder unit for processing. But I am honestly not sure of the effect of this on the head positioning.
30. Comment on the cleaning requirements of DASH
It is a certainty that cleaning by cotton wool or cotton buds is a no-no. There must be a special cloth used to do so and some alcohol spirits to be used. User cleaning is limited only to heads and moving rollers - an expert in the field shold do the most cleaning.
31. How many tracks does a modular digital multitrack (MDM) have?
8 Tracks.
32. How can more tracks be obtained?
More tracks can be obtained by connecting together up to 8 MDMs, thus giving a total of 64 tracks. The clock and the timecode from the master machine are distributed across all machines to keep them all in synch.
33. Comment on the types of usage of ADAT and DTRS machines?
One of the main advantages of a disk-based recording system is the ability to provide non-destructive editing -- not only familiar features such as cut, copy, paste, delete and erase, but also track slipping, the insertion of space, and track swapping. On-board DSP also allows time compression or expansion and pitch-shifting (±1 octave).Other main uses are synchronising to a sequencer, recording basic tracks and overdubbing.
13: www.jayglenn.com
16: www.videointerchange.com
24: www.soundonsound.com/sos/jul98/articles/digitalbasics3.html
33: www.soundonsound.com/sos/may00/articles/yamaha.htm
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Sun Apr 17, 2005 11:44 am |
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Quinnersboy
Joined: 22 Mar 2005
Posts: 4
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1.Why is it often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface?
An integrated disk system is often considered better because it is designed for that purpose and nothing else. Where’s a personal computer is designed to do many things, it’s cheaper which is an advantage but if something goes wrong who does one turn too. There are many different people you could turn to but they will all blame each other. If you have an integrated disk system then you simply just go to the manufacture because they made every part of it therefore they know what to do.
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
A tape recorder with 24 inputs and 24 outputs will have 24 tracks. No other format would be acceptable. If a disk recorder was to replace a 24 track tape recorder then the fewest number of inputs and outputs to be used would be 2 and as many as 24 or more can be used if the disk is fast enough to access the data. In saying this only two tracks can be recorded at any one time and the only output that could be used would be the main outputs.
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
The main limitations would be the speed of the disk. The speed can determine how quick the disk can access the data. Also when the data is fragmented then the access time slows. The conclusion is that then the number of tracks a system may be capable of is not steady.
4. What information is stored in the session file?
The information sorted in a session file would be the following. The track assignments, the edits made, the audio files used and the project title are all located in the session file.
5. Are session files usually transportable between different systems?
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
Yes session files can be transportable between different systems but it can’t be done very easily. An example would be that if you recorded and edited your music on a software platform like pro tools with 16 inputs and 16 outputs and then mixed also with pro tools using a desired amount of plug ins in a certain order. Then tried to play back on another system with only 8 inputs and 8 outputs then a great deal of work will have to be carried out in order to get some likeness of the two tracks.
SCSI is an old form of disk used for audio recording. That doesn’t mean that it is not suitable. In fact it has advantages over the other forms in the way that it can be connected as an external component to the computer. Also they can be connected together by daisy chaining on a buss so that several can be connected at the same time. Being a parallel interface, the data doesn’t just travel down a single wire, instead it travels down several wires therefore making data transfer much quicker than USB or firewire.
ATA is the most common disk interface used today. The reason for this is that they are cheap. In saying that these are not the fastest nor can huge amounts of external disk be added, in fact it is limited. Although some systems can allow you to install a ATA disk in a removable cartridge.
Firwire is fast but still not as fast as the modern SCSI versions. IN saying that firewire has some things that SCSI would like to have. Devices can be connected and disconnected without the need to shut the entire system down. It has thin flexible cable and connectors that can stand a bit of abuse. Also the firewire can self configure which means that no ID numbers have to be set by the user.
6. What is 'fragmentation'?
Fragmentation is a term used to describe when the disk is unable to assign flanking disk space and normally occurs when the disk is nearly full or when the disk has being used over a long period of time with out being erased.
7. Comment on archiving to CD-ROM.
Archiving to a CD-ROM is one way storing data fro long periods of time. Archiving to a CD is one way but not necessarily the best way as, you will not have any assurance that it will be able to be read in 40 – 50 years time. Optical is considered the best solution. With CD-ROM you can only hold a certain amount of data too. 700 megabits per CD. So if large amounts of data have to be sorted then multiple CD’s will be required.
8. What are 'virtual tracks'?
Every type of tape recorder has the same number of inputs outputs and tracks. Disk on the other hand has no fixed number of inputs and outputs and tracks. The number of tracks that can be played back one after another can be limited but many disk recorders can store extra tracks, which are known as virtual tracks. These tracks are in time with the standard tracks but have no designated output. Standard and virtual tracks can be exchanged and as systems are becoming more able to play more tracks one after each other then virtual tracks will become a thing of the past.
9. What is meant by 'edit density'? What are the implications of high edit density?
When data is stored on a disk then the data is retrieved simultaneously. If editing takes place then sections are deleted and or moved around to create the desired effect, then the head in the disk has to move around a lot to retrieve the data. The reason for that is that the data is now not in a continuous line, it’s all over the show. As more and more of this occurs then the number of tracks that can be played simultaneously decreases. Edit density is a term used too describe the data and it’s position on the disk. The length, the proximity to each other all affects the edit density. The smaller tightly packed sections cause the disk to work harder than normal. If high density becomes a problem then the number of tracks that can be played simultaneously can be dramatically reduced. To solve this problem, two or more disks could be connected together to share the tracks reliving the pressure of the one disk and expanding it out among two reducing the load.
10. Does the editing and trimming of regions delete audio data from the disk?
No, the disk is divided up into a number of regions. The good audio is separate from the audio that is not useful. This audio data that is not being used or that is deleted is still on the disk but will not be played back, it’s just silenced. This is also the story with the data that might be used again. You just silence the audio that you don’t thing you need and if you decide later on that you do need it then all you have to do is just retrieve it.
11. In editing, what is the difference between 'slip' and 'grid' modes?
Slip mode is a mode that allows you to place an audio section anywhere that pleases you regardless of any time code or grid values. An example would be if you have a section of guitar and then you place a section of bass slightly over the guitar section then the bit of the guitar section that was overlapped with the bass will be cut off. Often vocals and guitar tracks are comped together with this mode.
Grid mode is a mode that is similar to slip mode but this time this mode keeps the section, which you are placing in, in musical time of the piece. So it means that the pieces are always to a “quantization value”. So the section can be to musical values like quarter notes or eighth notes or to time code values. The most common application of this mode is when editing drum parts for timing. It’s really fast to drop each drum hit to a certain timing value that is relevant to the song. Once again the overlapping can be done in the same way as I described above for the slip mode.
12. When might it not be possible to create a crossfade?
It’s not possible to create a crossfade if there is no audio on the disk that extends past the section borders. This data is the data used to create a crossfade. When two sections are placed right up against each other then a crossfade can be made if there is data past each other’s boundaries. If not then a crossfade cannot be made. Even if there is some data, a crossfade might not be able to be made because there might not be enough data to work with. So one has to make sure that there is data beyond the sections border and that there is enough of that overlay to work with.
13. What is 'bouncing', in the context of mixing?
Bouncing in the context of mixing is when several tracks are taken and mixed together and put into one or two tracks, one for mono or two for stereo. For example all the vocals can be taken and bounced into one or two tracks freeing up multiple tracks leaving room to record further tracks. To do this a synchronized output from the record head is used so the bounce is in time with the rest of the tracks. When a bounce is done some sound quality is lost but this can be put up with.
14. What is meant by 'latency'?
Latency is a term used to describe time delay between recording and hearing of the recorded sound from the soundcard. The reason that there is latency is because the sure distance the signal has to travel through different stages to get to the final source. The signal first gets converted from an analogue signal to a digital signal through a converter, which gives a mere millisecond of delay. Then the converted signal goes through a digital buss within the soundcard. Once it goes through the digital buss then it moves onto the PCI buss, which connects the soundcard to the motherboard of your computer. From the motherboard it travels thought the rest of the computer until it reaches the operating system. This is the biggest task for the signal to overcome. Modern pc’s do a little bit of everything in turn in order to keep things running. A computer being a computer many problems can occur causing the computer to be tied up doing something. Therefore every soundcard has a buffer. As the delay prolongs the sound data build up causing a tail back if you like. This is sorted up in the buffer on the soundcard until such times, as the computer is ready to deal with the data. As long as there are enough buffers of good size then enough data can be sorted to ensure a good smooth transfer. So as you can see some delay can happen in the process and this is how latency came about.
15. What is the difference between DSP processing and host-based processing?
??
16. Was DAT originally intended as a professional or a domestic recording medium?
DAT was originally meant to be for domestic recording to replace the compact cassette or just a cassette. As the DAT tape is small just like the regular cassette tape is was rather to small for the professionals. They felt that if the tape was bigger then the data would have more room and less error cover up could be achieved. So the larger DAT tape was introduced for the professional market.
17. What is the sampling rate of standard DAT?
The sampling rate of standard DAT is 44100 or 16-bit.
18. What is the resolution of standard DAT?
The resolution of a standard DAT is 16 bit.
19. What is 'azimuth recording'?
Azimuth recording is a term used to describe the position of heads in a recorder. The angle of the head gap, where the head recording takes place and the tape track itself. Is azimuth recording. Mainly found in DAT machines two heads are used. One of the heads is set to +20 degrees of center and the other head is placed at – 20 degrees of center. Then each head lays down tracks alternately. When playback begins then each head receives a strong signal from the tracks in which recorded before. The bordering tracks then are discarded totally because they give such a weak signal because they are crooked by 40 degrees.
20. Describe the head wheel in DAT recorder.
A DAT recorder is similar in ways to a video recorder in the way that they both use a rotary head drum where both the playback and recorder heads are mounted. The difference between the video and DAT recorder is that a video always needs contact with the tape in order to build up a frame to display on the screen. Also the tape speed has to be constant too, to allow for smooth imaging. Therefore tape is wrapped nearly the whole way around the head drum to obtain this. However in the DAT recorder the head drum is smaller than it’s counterpart the video and the tape is only wrapped a quarter the way around it. The data can be read of at any rate and stored in a buffer and then read out at a constant speed and changed into a suitable audio signal. The head drum is a tiny 30mm in diameter and spins at a total of 2000 rpm.
21. What is SCMS?
SCMS stands for Serial Copy Management System. This system was developed to protect the record companies and their copyright of records in which they released. Even though this system stops a DAT machine making a copy or multiple copies this is not the case with the analog machines. Analog machines can easily make a copy from the original copy with a slight loss in quality but not all that noticeable to the human ear. Then this process can continue and continue, resulting in an endless amount of cd’s. SCMS doesn’t stop private copies being made it just prevents people who have recorded there own material from making perfect digital copies.
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
For a DAT recorder to be able to do near-simultaneous off-tape recording then there must be an extra pair of heads present on the drum. This would not be common on most DAT recorders but can be got as an optional extra if desired.
23. What is the sub-code area of the DAT tape used for?
A sub-code area of a DAT tape is used for extra data to be recorded along side the data already recorded.
24. What is 'interleaving'?
Interleaving is a method used by DAT machines to scatter data so that when a drop out occurs or data is lost then enough data around that point which was lost can be used to rebuild or reconstruction the data lost.
25. What is the width of the tape used for 24-track DASH?
The width of a 24-track tape is 6.3mm or ¼”.
26. What is the width of the tape used for 48-track DASH?
The width of a 48-track tape is 12.55mm or ½”.
27. Describe how 24-track and 48-track DASH machines are compatible.
24-track machines and 48-trcaks machines are two way or totally compatible. If you had 24-track machine and you start to record then as you work your way through the project you decided that you haven’t got enough room with just 24 tracks. You decided to put all on a 48-track machine. As both machines are compatible with each other there is no problem. So the 24 tracks you recorded on the 24 track machine can be simply put onto the 24 track tape on the 48 track machine and use the other 24 tracks in the guard bands left by the 24 track machine. Maybe you decided that there was no point in doing this procedure and you decide to go back to your original 24 tracks. So the now 48-track tape can be put back on the 24 tracks machine and the original 24 tracks can be smoothed out and used and the later 24 tracks can be deleted leaving you with a perfect mix on 24 tracks. So this shows that a 24-track machine and a 48-track machine are totally compatible with each other.
28. How are DASH tapes edited?
DASH tapes are edited by coping the tape to, two different machines and synchronizing them together with a slight offset. It makes good sense that two machines are better than one. You can be more versatile with two 24-track machines than just one 48-track machine.
29. In DASH, why does a playback head come before the record head in the tape path?
An analog machine processes a signal almost instantly where digital signals or DASH are delayed slightly when being processed. For this reason it is necessary to have the playback head first before the recording head. When overdubbing is being carried out in an analog machine the signal that is synchronized during play back comes from the record head and not the play head. If this same set up was used in a DASH machine then the signal would firstly be delayed slightly from the playback signal being processed and delayed even further when the record signal is processed and put onto tape. Something like 75mm of tape or 105 milliseconds would be the difference. So to perform synchronized overdubs there has to be a playback head in the path first before the record head or the task of multitrack recording would not be able to be carried out.
30. Comment on the cleaning requirements of DASH
Unlike an analogue machine a DASH machine cannot be cleaned with a cotton bud and some alcohol. A DASH machine also cannot be cleaned by a sound engineer. An expert has to be called in too do the job. They use a special chamois- leather-cleaning tool to carry out the cleaning of the head of the DASH machine.
31. How many tracks does a modular digital multitrack (MDM) have?
A modular digital multitrack (MDM) has 8 tracks available to work with.
32. How can more tracks be obtained?
To obtain more tracks multiple machines can be hooked up together and synchronized to obtain more than 8 tracks.
33. Comment on the types of usage of ADAT and DTRS machines?
ADAT machines are most commonly found being used in small time recording or budget recording studios. For demo cd’s or something small scale. This machine is ideal because it can only record a max of 60 minutes in total.
DTRS machines are most commonly found being used in film post production and broadcasting. It can hold a total of 108 minutes of recording. |
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Sun Apr 17, 2005 1:27 pm |
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chemira
Joined: 03 Jan 2005
Posts: 50
Location: Nova Scotia Canada Eh! |
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Week 6 Recording Techniques
1. Why is it often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface?
Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
It is often considered better to use an integrated disk system over a personal computer for several reasons. Firstly the integrated disk is designed for recording and playback as per the intended design specification. A 24 track integrated disk with 16/44.1 file format will be able to record 24 tracks at 16 bit, 44.1 MHz continuously until the hard drive space has been filled.
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
If a tape recorder has 24 inputs and 24 outputs the tape recorder would be a 24 track recorder. A taper recorder requires 24 inputs and 24 outputs to be a functionally direct replacement for a 24-track tape recorder.
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
A tape recorder with two inputs and two outputs that is capable of 24 tracks would be limited in that the recorder could only record two tracks at a time and only output two channels for mix down or monitoring.
4. What information is stored in the session file?
The Session file keeps a directory of all of the files in a project their names and locations, modifications or edits. There are in some software samplers provisions for automation or mixer configurations for the project.
5. Are session files usually transportable between different systems?
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
Some Session files are transportable only if the systems share similar architecture. Automation of external hardware may be possible if it is similar on each system that the session will be shared on.
Small Computer System interface is a flexible fast architecture for connecting hard drives or optical devices to a computer. Hi Data transfer rates an multiple connections make this a boon for recording. ATA only allows two devices to share the same control in parallel ATA. Serial ATA is an improvement allowing 159 MBps transfer rates. Fire wire is a higher data transfer rate, up to 800MBps, hot swappable and multiple fire wire devices can share the same buss.
6. What is 'fragmentation'?
Fragmentation is when a files that are related become separated on the hard drive. Files may be form the same group or same folder or area of the hard drive.
7. Comment on archiving to CD-ROM.
Archiving to CD Rom is a long term file storage medium that if labeled and stored properly can save data over long periods of time. CD Rom creates a finalized disc that cannot be written to or tampered with after it has been completed. This allows long term storage (time sensitive) of large amount of data at a minimal cost. This is still one of the best cost per MB means of long term storage available.
8. What are 'virtual tracks'?
Virtual tracks are “takes” of tracks that have been recorded to a hard disk recorder. This hard disk recorder has a limited number of playback tracks or outputs available for playback but has an extended number of tracks for recording. This allows the engineer to try several takes of an individual instrument and utilize the best performance for the final mix. These virtual tracks can also be mixed down into mono or stereo sub mixes (usually a limited number at a time). These virtual tracks can immensely increase the potential track count of any hard disk recorder by utilizing this ping pong bouncing of tracks that has been used for many years in audio.
9. What is meant by 'edit density'? What are the implications of high edit density?
Edit density is a tern referring to the amount of changes or modification events that occur during a given mix. This density can consume higher CPU resources to the point that the audio is adversely affected at points where the track count and Edit density exceed the CPU’s processing limit. Dropouts may happen or limitations of track playback may also occur.
10. Does the editing and trimming of regions delete audio data from the disk?
Two methods can be utilized to trim audio in SONAR, Slip edit or trim clip or apply trimming. Slip editing keeps the track intact but moves the fade in and fade out points, apply trimming removes the unwanted portions of the track permanently saving data space on the hard drive.
11. In editing, what is the difference between 'slip' and 'grid' modes?
Slip and grid mode refer to the way editing by drag and drop is done. The slip method allows free movement of the file to any location in the track regarding time. Grid mode allows the file to be moved but only to preselected time events. The start of the file may be started at the beginning of a bar using ticks or beats, at the or on the seconds using real time or synchronized to a time code or marker.
12. When might it not be possible to create a crossfade?
13. What is 'bouncing', in the context of mixing?
Bouncing is the combining of tracks to create a new track of a lesser track count. The ability to take six drum tracks and mix then onto two tracks creating a stereo mix is a form of bouncing tracks. This saves four tracks in the process.
14. What is meant by 'latency'?
Latency is the time delay from when a sound is made or triggered until it is heard or recorded. There is a delay present in the analog to digital converters as they process the analog signal and convert it. The same holds true for the audio as it is sent out of the computer from the digital to analog converters. Latency is in audio the time delay experienced usually in the converters.
15. What is the difference between DSP processing and host-based processing?
DSP Processing utilizes a separate processor to facilitate the computations required to render the effects to an audio signal. Host based processing uses the same processor that the sequencer is using to facilitate these computations. The DSP processor will be able to render more and higher quality effects than a host processor.
16. Was DAT originally intended as a professional or a domestic recording medium?
DAT was originally intended to be sold as a consumer product but due to cost prohibition and copyright taxes levied on the blank cassette the DAT recorder stayed among the Pro audio circles. Quote” Although DAT was originally intended as a consumer-oriented digital replacement of the ubiquitous Philips analog cassette tape, its success was nipped in the bud primarily because it could be used to be make direct digital copies of compact discs. The U.S. recording industry, with the help of Congress, immediately sued Sony to prohibit sales of DAT gear in the United States and lobbied hard for a copy-protection scheme” Unquote. Although the technology and quality was high the price kept the consumer market at bay. [1]
17. What is the sampling rate of standard DAT?
48 KHz is the most frequently used sampling rate for DAT. [2]
18. What is the resolution of standard DAT?
A standard DAT deck resolution would be 16 bit.
19. What is 'azimuth recording'?
The tem azimuth refers to angles that objects are separated from each other. These angles in a tape deck refer to the separate tape heads having an angle which will give separation for each head to its adjacent tracks. This can allow better separation between tracks.
20. Describe the head wheel in DAT recorder.
The head wheel is the contact surface that picks up the data signal from the DAT Tape. This Wheel spins at 2000 RPM and is set at an angle to the tape. The head wheel will lay down diagonal strips of DATA on to the tape.
21. What is SCMS?
Serial Copy Management System is a form of piracy protections that sets a flag in the sub code of a tape so that no other copies may be made.
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
23. What is the sub-code area of the DAT tape used for?
The Time of the tape is recorded in the sub-code, start and end times and program numbers. This data is imbedded onto the tape as reference points.
24. What is 'interleaving'?
Interleaving is a data storage format that stores a string of data at pre determined locations relating to the speed of a disc. This will create a reduced spin time from the start of each string of data segments as the disc rotates.
25. What is the width of the tape used for 24-track DASH?
Half inch open reel to reel.
26. What is the width of the tape used for 48-track DASH?
Again Half inch open reel to reel.
27. Describe how 24-track and 48-track DASH machines are compatible.
The Two types of Machines utilize the same tape with the difference being there are spaces in between tracks on the 24 track recorder. This space between track on a 48 track machine will utilize the spaces to record tracks 25 to 48. A 48 track tape will only play back tracks 1 to 24 on a 24 track machine. The tapes are interchangeable the only limitation is the machine track count available.
28. How are DASH tapes edited?
Dash tapes may be edited by cut and splice methods or by bouncing tracks from machine to machine.
29. In DASH, why does a playback head come before the record head in the tape path?
In the event of bouncing tracks to another recorder the play head needs to “play” the track physically before the recording head records the track. This will enable the track to play and the new track can be overdubbed on another recorder at a known delay.
30. Comment on the cleaning requirements of DASH
A Dash Tape Deck should be cleaned by a qualified technician due to the specific materials cleaners and techniques that are needed to properly clean the machine. Proper alignment and electronic inspections should also be done by a qualified technician to ensure proper operation.
31. How many tracks does a modular digital multitrack (MDM) have?
A modular digital multi track like the Alesis ADAT will have 8 tracks
32. How can more tracks be obtained?
By synchronizing several ADATs together you can achieve higher track counts of typically 16 or 32 tracks.
33. Comment on the types of usage of ADAT and DTRS machines?
After ADAT was introduced it became the SEMI-PRO audio choice standard of most small recording studios. Relatively inexpensive, fair number of track counts, 16 Bit audio(20 bit new) linkable for higher multi track counts with a reasonable high standard of audio quality. Inexpensive tape cost with reasonably inexpensive maintenance costs compared to older multi track analog systems of the era. The ADAT created a compatible format with great transfer of 8 tracks via ADAT Lightpipe.
DTRS tape recorders such as the Tascam DA 8 are more expensive than the ADAT counterpart for similar track counts. Using 8mm tape which can hold 108 mins. These Multi track recorders are mainly used in Professional studios for post production work.
[1] http://www.videointerchange.com/audio_history.htm
[2] http://psbg.emusician.com/ar/emusic_whats_dat/
Last edited by chemira on Mon Apr 18, 2005 6:12 pm; edited 1 time in total |
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Sun Apr 17, 2005 8:42 pm |
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rachelh
Joined: 16 Jan 2005
Posts: 35
Location: Trinidad WI |
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RT- Week 6 - equipment 3
Submitted by Rachelh
1. Why is it often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface?
Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
It is often considered better to use an integrated disk recording system rather than one that uses a personal computer as the user interface because of the inherent lack of liability when problems arise in a PC based system, integrated disk recording systems are primarily built for the purpose of creating and editing music thus, liability is in the hands of the manufacturer if any problems arise. Disk recorders are quickly replacing tape multitrack recorders although, tape recorders are still considered to be a suitable means of mass storage especially in the visual medium.
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
A tape recorder having 24 inputs and 24 outputs would have 24 tracks. For a disk recorder to be a replacement for a 24- track tape recorder, the number of inputs and outputs would be dependent on the speed of the disk as in theory this defines the number of tracks that can be allocated, I would think that the minimum number of inputs and outputs would be 2 each it is all dependent on the speed of the disk, if the disk is fast enough to process additional data, 24 inputs and outputs can be utilised or even more. But generally disk recorders do not have a set precedent with respect to a correlation between the number of inputs and outputs being the same.
3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
The main limitations of a recording system that has two inputs and two outputs and was capable of twenty-four tracks would be the speed of the disk and the capabilities of the processor. The faster the disk in conjunction with the processor is able to retrieve and process data the less the limitations of the disk recording system.
4. What information is stored in the session file?
In the session file information pertaining to the name of the project, the tracks [how they are assigned], loops/ audio files used and editing which occurred are stored.
5. Are session files usually transportable between different systems?
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
Session files are usually not transportable between different systems as there is currently no universal compatibility between systems for this format. Thus, if you take one disk cartridge and load it into a disk recording system that is not the same as the one in which the data was originally stored/recorded, there will be problems with respect to reading the data if it is read at all. SCSI, ATA and FireWire are all interfaces. The SCSI interface allows for a disk to be connected externally to a system or to be daisy
chained to a system, ATA does not allow for external disk connection, FireWire however is not a disk, it is as previously mentioned an interface. With respect to audio recording and speed, SCSI is the best medium; ATA and FireWire are not as fast as SCSI.
6. What is 'fragmentation'?
Fragmentation is when data stored on the hard drive is broken up into pieces, due to data being moved, re-written or deleted. Fragmentation slows down the disk as a file may be broken up into many pieces and instead of being stored continuously onto adjacent clusters and sectors, thus, the disk head may have to skip over a few sectors to allocate a file in its totality slowing down file retrieval and processing.
7. Comment on archiving to CD-ROM.
Archiving to CD-ROM is a very effective system. CD ROM discs are in expensive and are a good medium for storing data only problem being that it is not suitable for storing immensely large amounts of data as the limits are usually beneath 700 megabytes.
8. What are 'virtual tracks'?
A virtual track is a track stored in memory that is synchronised with the tracks that actually exist. Virtual tracks allow disk-based recorders to store many variations of a track or many recorded tracks – as much as the memory permits, these tracks can be often switched with real tracks when need arises.
9. What is meant by 'edit density'? What are the implications of high edit density?
The term ‘edit density’ refers to the number of regions in on the disk that data is stored and their proximity in relation to one another, high density has the effect of slowing a disk down as the information for playback is so scattered that it takes time for the disk heads to locate the data, the higher the edit density, the less amount of simultaneous tracks would be allowed in the playback.
10. Does the editing and trimming of regions delete audio data from the disk?
Editing and trimming of regions does not delete audio data from the disk, it merely silences this data. Thus if the trimmed data is needed it can be easily recalled.
11. In editing, what is the difference between 'slip' and 'grid' modes?
In editing, the slip mode allows clips to be slipped into tracks without adhering to time and measure constraints where as the grid mode is regulated with respect to time and measure.
12. When might it not be possible to create a crossfade?
A crossfade can be created when we have two clips and we want to bring them together and have them flow one into the other seamlessly. It may not be possible to create a crossfade if there is no material before and after the parameters of the fade as it is this material that is needed to create the fade itself.
13. What is 'bouncing', in the context of mixing?
Bouncing in the context of mixing refers to the process by which similar tracks are combined onto one to free up other tracks and make them available for additional recording.
14. What is meant by 'latency'?
Latency is also known as delay. It occurs in the exchange of packets of data from one place to another. In audio, latency is the time that the audio is retrieved from the hard drive then heard or the time that audio is processed then heard with real time effects.
15. What is the difference between DSP processing and host-based processing?
DSP processing refers to digital signal processing, DSP processing is much faster than host based or computer based processing, as DSP is synonymous with lower incidences of latency. Because DSP based systems are designed around music production, they are designed to cope with audio signals as opposed to normal data that is written and stored onto a computer. Thus making DSP a more compatible medium when recording and playing back music.
16. Was DAT originally intended as a professional or a domestic recording medium?
DAT [Digital Audio Tape] was originally intended as a domestic recording medium hence the small size of the tapes. It was originally intended to replace cassettes and be the next step in that evolutionary chain.
17. What is the sampling rate of standard DAT?
The sampling rate of standard DAT is 48 kHz.
18. What is the resolution of standard DAT?
The resolution of a standard DAT is 16 bit.
19. What is 'azimuth recording'?
Azimuth refers to the head’s tilt in the plane parallel to the tape. The head gap should be perpendicular to the tape so that all track gaps are electrically in phase with each other. DAT uses two heads one is set at –20 degrees and the other at 20 degrees and tracks are laid down in an alternative manner. This allows for alternate tracks, which are misaligned at 40 degrees to be bypassed in the playback.
20. Describe the head wheel in DAT recorder.
DAT uses two heads one is set at –20 degrees and the other at 20 degrees and tracks are laid down in an alternative manner. This allows for alternate tracks, which are misaligned at 40 degrees to be bypassed in the playback.
21. What is SCMS?
SCMS or Serial Copy Management System arose out of the need to protect recordings from being unlawfully re-recorded. On a consumer DAT machine, the 44.1 kHz sampling frequency is often reserved for pre recorded DAT tapes and is designed to discourage this illegal recording. SCMS restricts digital copying by allowing for three options – copy permit [allows for a recording to be freely copied], Copy restrict [allows for only one copy of the recording to be made] and Copy prohibit [which forbids digital copying]
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
Near simultaneous off tape recording can be achieved via a DAT recorder as done in a three head analogue recorder by mounting an extra pair of heads on the drum of the recorder.
23. What is the sub-code area of the DAT tape used for?
The sub-code are of the DAT tape is used for storing information which allows for data and its respective audio information to be recorded beside each other. Information pertaining to times and events are logged into the sub code area if the DAT tape.
24. What is 'interleaving'?
In DAT interleaving is the technique by which the system is protected from dropouts. Interleaving works by dispersing data so that if any section of data is lost, the data, which is dispersed, will contain enough information in which to reconstruct the diminished damaged signal.
25. What is the width of the tape used for 24-track DASH?
The width of tape used for 24-track DASH is ½ inch.
26. What is the width of the tape used for 48-track DASH?
The width of tape used for 48-track DASH is ¼ inch.
27. Describe how 24-track and 48-track DASH machines are compatible.
24 and 48-track DASH machines are compatible due to the fact that if you are recording on a 24 – track DASH machine and you maximise your tracks and would like additional tracks to work with, you can simply transfer your material to a 48 track DASH machine and proceed as normal. A 48 track can be transferred to a 24 track DASH also; only difference will be that only the first 24 tracks will be useable.
28. How are DASH tapes edited?
Digital Audio Stationary Head [DASH] tapes are edited by playing back the material and copying the data onto another tape and editing out the unwanted parts and splicing together the remaining parts.
29. In DASH, why does a playback head come before the record head in the tape path?
In DASH, the playback head comes before the record head in the tape path because there is an inherent delay associated with digital operations thus the playback head has to be in function to allow the record head to know how to operate and to allow for synchronous overdubs and recording.
30. Comment on the cleaning requirements of DASH
Unlike Analogue tape recorders DASH requires a specially trained technician to come in and clean the machine. On an average of every 6 months the head should be aligned, once again, a specially trained technician should do this. If these procedures re not adhered to, considerable damage to the system could occur amounting to thousands of dollars in damages.
31. How many tracks do a modular digital multitrack (MDM) have?
MDM is capable of having 8 tracks.
32. How can more tracks be obtained?
More tracks can be obtained for a MDM by synchronising machines.
33. Comment on the types of usage of ADAT and DTRS machines?
ADAT [Alesis Digital Audio Tape] machines are mainly used in recording studios whilst DTRS [Digital Tape Recording System] is commonly used in postproduction for film as well as broadcasting.
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Reference: All material was researched via:
Modern Recording Techniques – DM Huber, R Runstein
Studio Recording Engineer
Sound and Recording – F Rumsey, T McCormick
Sweetwater.com |
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Mon Apr 18, 2005 2:48 am |
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AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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JohnA
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2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
A tape recorder with 24 inputs and 24 outputs will have 24 tracks. To be a replacement for a 24 track tape recorder, a tape recorder with 2 inputs and 2 outputs could suffice.
Hmm, not sure you have grasp the idea that here the questions wishes you to understand that for recording 24 signals at once, you need 24 inputs/outputs. - be careful. The key is in the word "replacement", in that often the output signals would be routed into a mixing desk and then onto performers headphones. You have clearly understood this concept in the following question.
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8. What are 'virtual tracks'?
A virtual track is the computer equivalent of a track taped on a multi-track tape recorder. This could apply to midi virtual tracks and audio virtual tracks.
Check this to be sure John. http://www.iaekm.org/article29.htm (AS WELL AS UNDERSTAND THE CONCEPT OF DIGITAL AUDIO VIRTUAL TRACKS)
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26. What is the width of the tape used for 48-track DASH? Also ½” open reel tape.
And 1/4" for both 24 and 48 machines.
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33. Comment on the types of usage of ADAT and DTRS machines?
ADAT and DTRS machines are both refered to as MDM’s. ADAT (Alesis Digital Audio Tape) machines are usually used in either home recording setups or recording studio setups, and has become the most widely used professional digital recording system.
This is a bit "old" now.
hoaxwagon
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5. Are session files usually transportable between different systems?Yes if the systems are the same with the same plug ins available.
Doesn't make sense here, you should say no, and explain why.
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10. Does the editing and trimming of regions delete audio data from the disk? I believe as long as the undo feature is active, the last few trims are still on the disk and available for
recovery.
Yes this is system specific these days.
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22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape
recording?
I think you understand this now.
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24. What is 'interleaving'? Interleaving is the arrangement of sectors on a track so they are work well with the speed of the disk controller or head wheel.
This is poor and you need to ensure you have grasped this concept.
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29. In DASH, why does a playback head come before the record head in the tape path? Not sure but I think one reason why the playback head comes before the record head is to provide alignment of the tape.
Processing times.
You have good skills at condensing the answers, however, be very cautious as they are ALL a little OO brief. I'm aware of the work load you have, but I'd like to see more expansive answers.
Freshwayne
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7. Comment on archiving to CD-ROM.
Cheap archiving system,good software support available,can hold up to 80 mins at 44.1 kHz stereo signal to sixteen bits per channel. In terms of data it can hold 650 megs which is condsiderable.
This is not a very clear answer Wayne, ensure you read up to present the issue of "archiving".
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19. What is 'azimuth recording'? Azimuth recording is a type of recording where the heads need to be absolutely vertical with respect to the tape (I think?).
Please check this one.
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22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording? I honestly couldn't find anything on this anywhere.
Do you fully understand this now, after considering how the heads are constructed?
Generally good stuff, well done.
Quinnersboy
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3. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
The main limitations would be the speed of the disk. The speed can determine how quick the disk can access the data. Also when the data is fragmented then the access time slows. The conclusion is that then the number of tracks a system may be capable of is not steady.
OK, here we see you missing the point, the question is asking you what are the limitations, you have not really stated them. What are they? What are the limitations of not having 24 inputs and outputs?
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4. What information is stored in the session file?
The information sorted in a session file would be the following. The track assignments, the edits made, the audio files used and the project title are all located in the session file.
Don't forget VST and plug-in information.
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6. What is 'fragmentation'?
Fragmentation is a term used to describe when the disk is unable to assign flanking disk space and normally occurs when the disk is nearly full or when the disk has being used over a long period of time with out being erased.
I think you understand this but I'm not sure of the term "flanking disk space".
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15. What is the difference between DSP processing and host-based processing? ??
Do you understand this now, you know dedicated processors are available on specific hardware?
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16. Was DAT originally intended as a professional or a domestic recording medium?
DAT was originally meant to be for domestic recording to replace the compact cassette or just a cassette. As the DAT tape is small just like the regular cassette tape is was rather to small for the professionals. They felt that if the tape was bigger then the data would have more room and less error cover up could be achieved. So the larger DAT tape was introduced for the professional market.
This contains a bit of "waffle".
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23. What is the sub-code area of the DAT tape used for? A sub-code area of a DAT tape is used for extra data to be recorded along side the data already recorded.
Yep but you want to mention the type of data where you can.
Good answers, though you should try to be more concise and direct in your answers. I want to see you trying to | | | |
