AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
|
| Week 6 |
 |
|
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
|
Mon Oct 03, 2005 4:10 am |
|
|
thx1138
Joined: 07 Jan 2005
Posts: 21
|
|
|
|
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 multi-track recorders.
An integrated disk recording system is often considered better than a personal computer based system as the integrated disk recording system is dedicated solely to the job of recording. Rather than a mouse and keyboard the user would control the integrated disk recording system with interfaces specifically for the task with dedicated controls with many sliders and rotary controllers.
A computer-based system isn't entirely dedicated to being a disk recording system plus there is a reliance on software that may not be entirely compatible with other software. Each piece of software/hardware is likely to be made by a different manufacturer and the computer's resources are not entirely given over to the process of recording.
With a stand alone disk recording system all its components would be made by the same manufacturer and compatible with one-another plus all the components would be entirely dedicated to the process of recording.
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 it will have at least 24 tracks. If the tape recorder were to be replaced by a disk recorder then the disk recorder would require at least the same amount of inputs, outputs and tracks as the tape system.
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 disk recording system has 2 inputs and two outputs and is capable of 24 tracks then the main limitations would be that you could only record two tracks at a time and with only two outputs you would only be able to output the 24 tracks in stereo.
4. What information is stored in the session file?
A session file would contain information regarding the audio files and any edits made to those files and their positions within the session. Mixing information such as panning and volume, plug ins used and their settings and the name of the session itself.
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 not usually transportable between systems, as not all systems are similar.
SCSI is old technology but still suitable for audio recordings as it has a fast data transfer rate and many storage devices can be daisy chained together plus it is a parallel interface. It's not hot swappable though and device ID's need to be set for each SCSI device.
ATA can be used but it only allows for the connection of 2 devices, it is cheap but is not the fastest medium for transferring data.
Firewire is also suitable for audio recording as it is quite fast plus its cable is a lot smaller than SCSI devices. It is also hot swappable so the system need not be turned off to unplug and plug in Firewire devices, though some manufacturers of Firewire devices do recommend that you do turn your system off before plugging/unplugging Firewire devices. Also, unlike SCSI, the user does not need to specify an ID for each Firewire device attached.
6. What is 'fragmentation'?
Fragmentation is when a file is not stored in contiguously in one place on a disk. If enough space cannot be found to store the entire uninterrupted file it will be fragmented and bits of it will be stored where ever there is space.
7. Comment on archiving to CD-ROM.
Archiving to CD-ROM is a cost-effective form of long term storage. The average size of a recordable CD is 500 to 800 MB so it may not be suitable for backing up your entire hard drive but it is a more than adequate medium for say storing all the files for any given project/session.
8. What are 'virtual tracks'?
Virtual tracks are the different 'takes' of each main track so that you have multiple takes of each track to play with when mixing down.
9. What is meant by 'edit density'? What are the implications of high edit density?
Edit density refers to the amount of editing and modifications that happen during a mix to the audio files within it. The implications of high edit density is increased CPU usage where the amount of tracks used and the edit density can overload the available processing power of the CPU affecting playback and causing problems such as dropouts and stuttering in some tracks.
10. Does the editing and trimming of regions delete audio data from the disk?
The editing and trimming of regions does not delete audio data from the disk. While an audio file can be edited within a disk recording session the actual file itself will remain unchanged.
11. In editing, what is the difference between 'slip' and 'grid' modes?
In editing the difference between slip and grid modes means that in slip mode an audio file can be placed at any point within a track whereas in grid mode, an audio file can only be placed in certain slots regarding time so that the audio file starts at the beginning of a bar or at certain slots within the bar.
12. When might it not be possible to create a crossfade?
It may not be possible to create a crossfade when audio files do not overlap or when the file does not have data that extends past the beginning or end of a region.
If two files do not overlap then a crossfade cannot be made.
13. What is 'bouncing', in the context of mixing?
In the context of mixing 'bouncing' is when multiple tracks are mixed down into one or two tracks (mono or stereo). This frees up other tracks when several tracks are bounced down onto another track.
14. What is meant by 'latency'?
Latency is a term that describes the time it takes from a request for an action to be carried out to the actual action occurring. It is the time it takes for data to go through a system.
15. What is the difference between DSP processing and host-based processing?
DSP is digital signal processing and it uses a separate processor to render effects to an audio signal, this can be done within software or a specific processor on a hardware device. Host based processing is when the same processor the sequencer is using (i.e. the host computers processor) is also used for any effects to an audio signal.
16. Was DAT originally intended as a professional or a domestic recording medium?
DAT was originally intended for domestic use to replace the compact audiocassette. DAT is a recording and playback medium introduced by Sony in 1987 though its copy protection system rendered it a bit useless for domestic use.
17. What is the sampling rate of standard DAT?
The standard rate of sampling of standard DAT is 44.1 kHz though it allows for four sampling modes: 22 kHz at 12 bits, 32 kHz, 44.1 or 48 kHz at 16 bits. Some recorders operate above the standard and allow 96kHz at 24bits.
18. What is the resolution of standard DAT?
The resolution of standard DAT is 16 bit.
19. What is 'azimuth recording'?
Azimuth recording is a technique to overcome crosstalk between different recorded tracks on a tape. One head is twisted 20 degrees to the left and the one the same amount to the right. This creates a 40-degree azimuth error between them. This means that while each head will replay its own recorded track on the tape it will minimise the amount of crosstalk from adjacently tracks. This also means that guard bands, which are the buffer zones between tracks on a tape where nothing is recorded, are not needed and allows greater packing density on the tape.
20. Describe the head wheel in DAT recorder.
Most DAT recorders use a rotary head system in which the tape is partially wrapped around a rotating drum that contains a number of record/replay heads. As the tape spirals around the rotating head the heads trace a diagonal hollow stripe across the width of the tape. The drum rotates very quickly (around 1500 rpm) which gives a fast tape to head and data transfer speed.
21. What is SCMS?
SCMS stands for serial copy management system, which amusingly enough seems to be pronounced 'scums'. It is a method of preventing unlimited cloning of DATs. It is a bit flagging system to prevent digital copies being made of digital audio such as DATs and CDs.
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
In order for a DAT machine to be capable of near simultaneous off-tape recording then the drum would require an extra pair of heads.
23. What is the sub-code area of the DAT tape used for?
The subcode area of a DAT tape carries the start, skip and end Ids, program numbers and date and time stamps.
Another set of sub-codes are recorded within the audio data such as audio or data modes, emphasis status, sampling rate, normal or long play modes and copy prohibit.
24. What is 'interleaving'?
Interleaving is a technique used to scatter data in such a way that if a large section of data is lost or damaged due to media failures such as dropouts on a tape or dirt on a CD, when the data is reordered smaller manageable data losses are formed which error detection and correction systems can then deal with.
It is a standard element in the error protection process. If a section of data was lost due to a tape dropout, the large missing block of data that would otherwise defeat error protection becomes several smaller blocks, which are retrievable.
25. What is the width of the tape used for 24-track DASH?
The width of the tape used for 24 track DASH (digital audio stationary head) is half an inch.
26. What is the width of the tape used for 48-track DASH?
The width of the tape used for 48 track DASH is the same as that used for 24 track DASH, half an inch.
27. Describe how 24-track and 48-track DASH machines are compatible.
The size of the heads in the earliest DASH machines limited the number of tracks to 24. Newer machines with smaller thin film heads enabled another 24 tracks to be slotted in between the existing 24 giving 48-track recording.
A 24-track tape will play on a 48-track machine leaving 24 tracks blank and a 48-track tape will play on a 24-track machine though only the first 24 tracks will be picked up by the heads.
28. How are DASH tapes edited?
A DASH tape can be edited in the good old-fashioned way of cutting the tape and splicing it back together again.
29. In DASH, why does a playback head come before the record head in the tape path?
The play back head on a DASH machine comes before the record head because the digital signals are delayed when being processed before they are recorded to tape as opposed to almost instantly with an analogue tape machine. When overdubbing, the delay is compensated by having the playback head before the record head to enable synchronised overdubs and multi-tracking.
30. Comment on the cleaning requirements of DASH
A DASH tape deck should be cleaned by a qualified technician and cannot just be wiped with cotton wool and alcohol. The head should also be aligned on average once every 6 months by a specially trained technician.
31. How many tracks does a modular digital multi-track (MDM) have?
A modular digital multi-track (MDM) has 8 tracks.
32. How can more tracks be obtained?
MDM recorder and controller units can be combined to create a greater number of tracks.
33. Comment on the types of usage of ADAT and DTRS machines?
ADAT (alesis digital audiotape) is used in many pro, semi-pro and home studios. DTRS (digital tape recording system) is standard in television and film dubbing plus music-for-film applications.
References:
Sound & Recording fourth edition
Music Engineering second edition
www.sfu.ca/sca/manuals/zaapc/m/modular-digital.html
www.soundonsound.com/sos/jul98/articles/digitalbasics3.html
http://en.wikipedia/wiki/digital_audio_tape
www.soundonsound.com/sos/aug98/articles/digitalbasics.html
_________________
AcousticalWeaponsDivision/Alex |
|
Thu Oct 06, 2005 2:00 pm |
|
|
|
|
AndyBarber
Joined: 09 Sep 2005
Posts: 18
Location: North Wales |
|
|
|
Posted: Mon Oct 03, 2005 2:10 pm Post subject: Week 6
Andy Barber
--------------------------------------------------------------------------------
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.
With an external drive, reading and writing audio data is unimpeded by requests of OS system and is built especially for audio recording
Stand alone multi-track recorder
Hard disk based, Mini disk based system which can store, mix and process audio in digital domain within one system. Everything is integrated providing fewer cables and real life faders and knobs. More compact than analogue multi-track recorder making it more portable for use in a number of different environments. Doesn’t come with computer problems such as software, driver issues, viruses and crashing. Own central DSP engine built powerful enough to cope with maximum workloads without need to upgrade every so often. However, cant use plugins, has small display and may not have CD burner
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?
The tape recorder can hold a minimum of 24 tracks and can only record 24 (or 12 tracks of stereo) at a time. A disk recorder requires 2 inputs to be able to record a stereo track. If it was to replace a 24 track tape recorder it would also have to have 24 inputs and 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?
Firstly you would only be able to record and export two audio tracks simultaneously. Disk capacity and throughput (amount data that can be sent to and from the disk per second) value are main constraints of a disk recording system.
4. What information is stored in the session file?
A session file contains all the information of a recorded multi track song. Multiple mixes of a song can be saved. The file contains information about which tracks are used along with how it is mixed, panned and processed. Stores and recalls all settings of a mix.
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 specific to their own system and cant be transported to a different format/system
Interfaces that computer uses to transfer data from one component to another
A disk’s throughput capacity defines the number of tracks that can be read/played simultaneously not the way in which it is connected.
SCSI supports up to 16 devices including host adapter (fast data transfer)
IDE/ATA supports only 2 internal devices, slower and not really suitable
Firewire supports up to 63 devices, allows multiple speeds on same bus and high bandwidth for
multimedia operations. Its also hot swappable and device ID isn’t required as with SCSI
6. What is 'fragmentation'?
Files saved on hard disk try to be kept in the same location/cluster. Over time files are deleted leaving gaps on the drive. When programs and files are added or updated the drive it fills the gaps breaking up the cluster. This causes extra head movement slowing down disk access time
7. Comment on archiving to CD-ROM.
Hard disk data needs to be backed up to a physical medium. Audio files are large, backing them up allows space for new project to be started. CD-R is the least expensive method to long term file storage.
Disadvantage of slow reading and burning speed.
8. What are 'virtual tracks'?
A recording system may only have 2 inputs and outputs (1stereo pair) but can be capable of recording as many tracks as you like, only limitation being the hard drive. More than 2 audio tracks can be played back by the use of ‘virtual tracks’. All virtual tracks are mathematically mixed down to 2 channels for output
Allows capacity for many alternative takes of a track and is bound to the digital domain.
9. What is meant by 'edit density'? What are the implications of high edit density?
The amount of editing and processing of audio files in a mix is measured by edit density. High edit density and large track counts can put a lot of strain on the CPU causing timing problems and dropouts.
10. Does the editing and trimming of regions delete audio data from the disk?
Destructive edits directly affect and alter the original file
Non-destructive edits do not process the original file itself but instead just vary it during playback.
Editing and trimming regions doesn’t change the audio file on the hard drive, only the way in which it is played.
11. In editing, what is the difference between 'slip' and 'grid' modes?
These two modes refer to how an audio file can be placed in a sequencer. In slip mode the file can be placed anywhere along the time line In grid mode the file can only be placed at discrete sections broken up along the time line.
12. When might it not be possible to create a cross fade?
Cross fading is the process of fading 2 regions of audio together to prevent pops, clicks caused by sudden changes in sound. Cross fading in only possible when two audio tracks overlap.
13. What is 'bouncing', in the context of mixing?
Used in multi-track recording, bouncing means mixing down two or more tracks to a new track. If all your tracks are being used bouncing frees up tracks so more can be added. Tracks can also be bounced to an external 2 channel recording system to preserve a stereo track. After bouncing its not possible to change individual levels
14. What is meant by 'latency'?
Latency is time it takes for a signal to travel through a system. With multi-track recorders latency is the time delay between when the recorded track is monitored and then actually recorded
15. What is the difference between DSP processing and host-based processing?
Digital signal processing (dedicated to digital processing) uses as specialized microprocessor which is good for audio signals, video and telecommunications. Designed for Real time calculations it is highly mathematical with processing performed by numerical calculations
Host based only good for analysing data long after the acquisition. Their CPU power is used by many applications as well as processing audio signals, increasing latency. General-purpose microprocessors are not ideally suited to the numerically-intensive requirements of DSP, they have a simpler design but are much cheaper
16. Was DAT originally intended as a professional or a domestic recording medium?
Developed by Sony and Phillips. Initially intended to replace the analogue compact cassette audio tapes with a CD quality audio format. Later became standard for professional recording
17/18. What is the sampling rate of standard DAT? What is the resolution of standard DAT?
DAT are stereo and provide only 2 tracks
Standard allows 4 sampling modes
32KHz - 12 bit (long play, 6 hours on 3 hour tape)
32/44.1/48 KHz - 16bit
19. What is 'azimuth recording'?
Information on tape are recorded in strips which aren’t allowed to contaminate each other. To overcome cross talk between tracks guard bands (unrecorded areas between strips) can be used but will waste space on the tape.
With helical scanning the head drum usually contains two heads. Magnetic gap of both heads are tilted slightly left and right respectively (the ‘azimuth’ adjustment is the tilt of the magnetic head). The difference in tilt means each head won’t significantly read the other’s signal allowing stripes to recorded right next to each other.
20. Describe the head wheel in DAT recorder.
DAT recorders use a rotary head configuration implementing magnetic tape technology. Like videotapes it implements helical scan format of recording. Helical scanning or ‘striping’ allows recording at a higher bandwidth that would otherwise not be possible with a fixed head
Head rotates in opposite direction to tape increasing relative velocity. Head is tilted so that with each rotation a new area of tape is used. As tape is moving the diagonal strip is actually curved.
21. What is SCMS? (Serial Copy Management System)
Copy protection method allowing only one copy of an original DAT to be made
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
Some models have separate heads and electronics for recording and playback. This enables you to listen to a playback signal coming off the tape while recording. Play head after record head lets you know that the DAT is actually recording something.
23. What is the sub-code area of the DAT tape used for?
Sub-codes are included in signal data to indicate the start and end of tracks and index the tape. Users can skip to different tracks with a fast seeking time
24. What is 'interleaving'?
Arranging data in a non-contiguous way (not sharing a common boundary)
in order to increase performance. Data doesn’t get written to disk in the order it appears. Its is used in error detection and correction systems.
25. What is the width of the tape used for 24-track DASH?
Digital Audio Stationary Head . The format can record 8, 16, 24 or more channels of digital audio. 24 digital tracks can fit onto a ½ inch tape. Data recorded linearly with a stationary head
26. What is the width of the tape used for 48-track DASH?
Sony‘s 48-track PCM-3348 still works with a ½ inch tape
27. Describe how 24-track and 48-track DASH machines are compatible.
The original (24-track) format had always had space for 48-tracks but left half of the tape blank. The DASH cassettes used on both formats are the same. The first 24-tracks on a 48-track recording will be heard on a 24-track machine
28. How are DASH tapes edited?
Because the data is coded linearly it can be physically edited by cutting and slicing like with an analogue tape
29. In DASH, why does a playback head come before the record head in the tape path?
Digital heads in DASH cannot record and play at same time. Overdubbing problems are addressed by using a second write head after read head using digital delay to sync playback with incoming audio.
30. Comment on the cleaning requirements of DASH
Cleaning a head requires disassembly of machine and should be carried out by a qualified technician. Abrasive type head cleaners are available but should be used sparingly. Clean head by hand using a lint free cloth dampened with a low moisture liquid (99% alcohol).
31. How many tracks does a modular digital multitrack (MDM) have?
Modular Digital Multitracks. The standard format of MDM is 8 tracks with 16bit digital audio recording
32. How can more tracks be obtained?
MDMs have internal clock sources so multiple machines can be linked creating larger multi-track configurations.
33. Comment on the types of usage of ADAT and DTRS machines?
Inexpensive (relatively low cost) 8 channel multi-track digital recorder
Both are pro audio recording methods. DTRS has become a standard in TV, film dubbing and video post-production due to its built in time code and MIDI synchronization facilities. With sample accurate timing it makes interfacing with a video source and a MIDI sequencer easy. Slowly being replaced by computer based DAW.
http://ccrma.stanford.edu/courses/192b/lectures/6/6.html
http://www.luminous-landscape.com/tutorials/hd-back.shtml
http://audiotools.com/dat.html
http://www.minidisc.org/dat-heads-faq.html
http://www.osta.org/technology/cdqa3.htm
http://arts.ucsc.edu/ems/music/equipment/digital_recorders/Digital_Recorders.html
http://www.dsptutor.freeuk.com/
http://en.wikipedia.org/wiki/Hard_disk
http://www.webdevelopersjournal.com/studio/drives.html
http://en.wikipedia.org/wiki/Helical_scan
http://www.teac.com/GX1.html
http://en.wikipedia.org/wiki/Sound_recording
http://studio-central.com/multi_track_recorders.htm
http://www.digitalprosound.com/Features/2000/Sept/RecCD4.htm
http://www.soundonsound.com/sos/aug98/articles/digitalbasics.html
http://www.midiweb.com/info/library/digital-audio.shtml |
|
Fri Oct 07, 2005 7:49 am |
|
|
Polarman
Joined: 24 Jun 2005
Posts: 55
Location: Barbados |
| Week 6 |
|
|
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?
Advantages of an integrated disk recording system over a personal computer are that the integrated disk system is designed for recording only. It has been built, tested and tweaked for the purpose. If problems or questions arise there is one point of contact since the whole system has been designed by one company. A computer is built for other purposes then audio. The hardware can be manufactured from many different companies and sometimes a specific hardware doesn’t work with the rest of the computers hardware, some software doesn’t work with a specific hardware etc. Some people also have the view that an intergrated disk recording system lets you concentrate on your music rather then loose time on upgrading, installing plug-ins, debugging etc.
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 would have 24 tracks. A disk recorder would need (at least) 24 inputs and outputs to replace 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?
The main limitation would be that you are only able to record two tracks at a time. There are also limitations when it comes to adding effects since you only have two inputs/outputs if there are no additional sends or returns.
4. What information is stored in the session file?
The information stored in a session file is the track assignments, mixer settings, the edits, the audio files used, project title, VST and plug-in information.
5. Are session files usually transportable between different systems?
No usually not since different systems uses different structures to save the data. Open Media Framework Interchange (OMFI) is a platform independent file format intended for transfer of digital media between different applications. Cubase SX can import and export OMF files (file extension .omf), allowing you to use Cubase SX in conjunction with other audio and video applications.
The exported OMF file will contain (or make reference to) all audio files that are played in the project (including fade and edit files). It will not include unused audio files referenced in the Pool, or any MIDI data. Video files are not included, but Cubase SX stores the start positions of Video Events in the OMF file, allowing you to manually import video files in another application that can import omf format like Protools (as usual it cost extra in Protools to be able to do that…).
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
In audio production its important with high sustain rates. The difference between these three alternatives is not so much the physical hardware as the difference in controllers and possible bandwith these can tolerate. SCSI is an old standard but is still suitable for audio recording. Firewire is better then ATA.
6. What is 'fragmentation'?
Fragmentation is when files gets divided into pieces scattered around the disk. Fragmentation occurs naturally when you use a disk frequently, creating, deleting, and modifying files. At some point, the operating system needs to store parts of a file in non-contiguous clusters. This is slows down the speed at which data is accessed because the disk drive must search through different parts of the disk to put together a single file.
This is why it is important to always defragment you audio disk after each session.
7. Comment on archiving to CD-ROM.
According to the technical pages of several CD manufacturers estimates vary widely as to the expected longevity of CD-ROMs are estimated to last anywhere from 30 to 200 years.
How the discs are handled and stored can greatly affect their life period. There are many things that the user does that can shorten a disc’s life. Fingerprints and scratches are the most common. It is especially important that writable CDs not have fingerprints on them before they are written, as the fingerprint can scatter the laser beam from the recorder. In this case, the data can be jumbled or not be recorded at all which can result in an unusable disc.
Stickers should be used only with the greatest of care. Labels that are applied off-center or with air bubbles and creases can cause the disc to spin out-of-balance. This is especially harmful in high-speed recorders and readers. Removing a label can also damage the disc’s surface, rendering it useless.
Its also importent what format you back up your work since standards changes during time. MAybe a good if you want to save a multitrack is to save the tracks as separate wav fiels instead of session file.
8. What are 'virtual tracks'?
Soundcards provide real tracks whose number is dictated by hardware limitations, just like stand-alone recorders, but software can offer virtual tracks. Virtual tracks are streams of audio read from the hard drive and mixed with others by the audio sequencer, quite often emerging as just a single stereo pair of real tracks from hardware sockets during mixdown. All the mixing, as well as EQ manipulation and effects, is carried out internally by the PC processor. The huge difference between a hardware recorder and the virtual tracks used by a modern MIDI + Audio sequencer is that the sequencer doesn't have the same restrictions when it comes to adding more tracks. If your PC can manage 50 simultaneous tracks of audio playback you can write arrangement with up to arrangement with 100 tracks of different instruments, as long as you never exceed 50 tracks at any single moment.
In the domain of MIDI production virtual tracks refer to tracks that exist only in MIDI
9. What is meant by 'edit density'? What are the implications of high edit density?
Edit density is the amount of edits you have in your project and the most significant factor in track counts. If your edit density is to high you will get dropouts and timing problems caused by to much workload for the PCU and your hard drive.
When an audio file is recorded it is recorded in long contiguous sections on the disk. The disk does not have to work hard to retrieve the data therefore many tracks can be replayed simultaneously. When material is edited, then the regions that are to be replayed are probably not continuous on the disk, so the heads have to move more often to retrieve the data. Ultimately, there can come a point where this affects the number of simultaneous tracks. The term 'edit density' is used to mean the number of regions, their length and proximity to each other (shorter, more densely packed, regions make the disk work harder) and how far they are physically separated on the disk. The greater the edit density, the fewer tracks will play. If high edit density is causing a problem, two or more disks should be used so that tracks can be shared among them.
10. Does the editing and trimming of regions delete audio data from the disk?
When an audio file is recorded it is recorded in long contiguous sections on the disk. If you have a non–destructive edit system on your sequencer this file will be the same even if you’re are trimming and editing. Its only the order how the contiguous file will be played back that changes.
11. In editing, what is the difference between 'slip' and 'grid' modes?
Slip and grid modes refers to how different regions or tracks can be moved in a sequencer. In slip mode the regions or track can be moved and dragged anywhere in the project. In grid mode the region or track wil always snap to the grid that has been setup. The grid can be setup according time or note values.
12. When might it not be possible to create a crossfade?
To be able to create a crossfade there has to be audio on the disk that extends beyond the region boundaries. It is this material that is used to create the crossfade. If there is no material beyond the region boundaries, or insufficient for the desired duration of the crossfade, then the crossfade cannot be created.
13. What is 'bouncing', in the context of mixing?
The term 'bouncing' in multitrack recording can mean two things:
a) mixing together similar tracks, such as backing vocals, onto fewer tracks to free up the original tracks for further recording. This is only necessary if there are limited amount of tracks or if the recording system cant handle more simolutaneous tracks.
b) It can also mean save your mix since there no need to record a mix to a separate medium such as DAT or CD, it can simply be bounced to disk as a stereo file. In some systems, bouncing can take place faster than real time, although real time bouncing is better for the proper functioning of mix automation and plug-in effects, and real time bouncing offers the chance of listening to the mix, just to make sure that it is correct.
14. What is meant by 'latency'?
Latency means the delay that occurs between one event and another. In workstations latency normally means the delay between outputs and inputs of the audio hardware. Low latency is very important when using a workstation channels as foldback when overdubbing.
15. What is the difference between DSP processing and host-based processing?
In a host-based processing system all calculations are done by the computer (CPU), all effects, processing, mixing etc. Audio signals are different in structure from standard computer data. This can give problems with latency and disk performance.
The alternative to host-based processing is DSP, or digital signal processing where using DSP chips specially designed for the purpose. Digidesign's Pro Tools, for example, uses DSP cards to perform mixing and plug-in effects. The latency of a DSP-based system is very low, of the order of 3 to 4 milliseconds. The cost of a DSP-based system is higher then a host-based system.
16. Was DAT originally intended as a professional or a domestic recording medium?
It was intended for the domestic market. The original purpose of DAT was to be a replacement for the Compact Cassette.
17. What is the sampling rate of standard DAT?
The sampling rate of a standard DAT is 48 KHz and 32 KHz on long play mode. Some domestic DAT machines have 44.1 as an option.
18. What is the resolution of standard DAT?
The resolution of standard DAT is 16 bit.
19. What is 'azimuth recording'?
The ‘azimuth’ of a tape head refers to the angle between the head gap, where recording takes place, and the tape track itself. In DAT, which uses two heads, one head is set at -20 degrees and the other to +20 degrees, and they lay down tracks alternately. So on playback, each head receives a strong signal from the tracks that it recorded, and the neighbouring tracks, which are misaligned by 40 degrees, give such a weak signal that it can be rejected totally.
20. Describe the head wheel in DAT recorder.
The DAT recorder uses rotary head like a video recorder which lays tracks diagonally across the width of the tape. The same heads are used for recording and playback. The head wheel spins 2000 RPM in the same direction the tape is moving and the tape is only wrapped a quarter the way around it.
21. What is SCMS?
SCMS was developed in response to record companies' needs to protect their copyright. It meant that you could only digitally copy one generation. SCMS restricts digital copying by setting certain bits in the data stream. There are three options:
Copy permit - a recording can be copied freely. Only professional machines allow this code to be set.
Copy restrict - a recording can be copied once, then its SCMS bits are set to Copy prohibit
Copy prohibit - Digital copying is not allowed.
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
A DAT recorder may be capable of near-simultaneous off-tape recording if an extra pair of heads is mounted on the drum then a simultaneous off-tape monitoring can be performed during recording.
23. What is the sub-code area of the DAT tape used for?
Sub Code areas allow extra data to be recorded alongside the audio information. This include:
A-time, which logs the time taken since the beginning of the tape
P-time, which logs the time taken since the last Start ID.
Start ID marks the beginning of each item;
Skip ID tells the machine to go directly to the next Start ID
24. What is 'interleaving'?
Interleaving is precaution against dropouts, which scatters the data so that if one section of data is lost, then there will be enough data beyond the site of the damage which can be used to reconstruct the signal.
25. What is the width of the tape used for 24-track DASH?
The width of the tape used for 24-track DASH is ½ inch (12.55 mm) open reel
26. What is the width of the tape used for 48-track DASH?
The width of the tape used for 48-track DASH is ½ inch (12.55 mm) open reel.
27. Describe how 24-track and 48-track DASH machines are compatible.
The 24-track is totally two-way compatible with 48-track They are both forward and reverse compatible. If you record your project on a 24-track and feel that you don’t have enough tracks you can just change to a 48-track and get 24 extra tracks. If you start on a 48 track and only use 24 track you can change to a 24 track and do you mix.
28. How are DASH tapes edited?
DASH was designed to be a cut-and-splice editing format like on a analogue tape but the most used way to edit on DASH is by copying between two machines synchronized together with an offset.
29. In DASH, why does a playback head come before the record head in the tape path?
The playback head on a DASH comes before the record head because digital operations take time while analog processes take place instantaneously. Since you have a delay processing the signal to put it on the tape, when overdubbing the delay is avoided with having the playback head before the record head.
30. Comment on the cleaning requirements of DASH
A DASH should be cleaned by an expert. To clean a DASH you need special tools and a DASH should not be cleaned with cotton like an analogue tape recorder.
31. How many tracks does a modular digital multitrack (MDM) have?
A modular digital multitrack (MDM) have 8 tracks.
32. How can more tracks be obtained?
Multiple machines can be easily synchronized to give more tracks.
33. Comment on the types of usage of ADAT and DTRS machines?
ADAT is used in pro-, semipro- and budget music recording studios
DTRS is used in broadcast and film post-production
Sources
_______________________________________________________________________
http://www.moneygrow.com/cubase-nuendo/previous.html
http://www.webopedia.com/TERM/f/fragmentation.html
http://www.ancestry.com/learn/library/article.aspx?article=2131
http://www.soundonsound.com/sos/aug99/articles/pcmusician.htm
http://www.sweetwater.com/insync/word/virtualtrack
Watkinson, J. (2001). The Art of Digital Audio, 3rd ed. Oxford, Focal Press
Rumsey, F. & McCormick, T. (2004). Sound and Recording: An Introduction, 4th ed. Oxford, Focal Press
Pohlmann, Ken C. (2005). Principles of digital audio, 5th ed. New York, McGraw Hill
Rumsey, F. (2004). Desktop Audio Technology, Oxford, Focal Press |
|
Sun Oct 09, 2005 12:21 pm |
|
|
|
|
K
Joined: 12 Apr 2005
Posts: 10
|
|
|
|
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?
ANSWER: it is considered better to use in integrated disk recording system because it only has one purpase , ro record and play back music , the machine is built spicficly for recording . a personal computer can also be used to record and play back music but an integrated disk recorder is considered better bacause , on a pc there are other programs .ie. micro soft word, games, the internet , etc , there fore the computer could crash possibly resulting in the loss of recoding data
Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
ANSWER:
2. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
ANSWER: if a tape recorder has 24 inputs and 24 outputs it will 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?
ANSWER: if a disk recorder was to a replacement for a 24 track tape recorder it would need 24 inputs and 24 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?
ANSWER: its main limitations would be that you would only be able in send the signal in sterio form , and that you could only record two tracks at once
4. What information is stored in the session file?
ANSWER: on a session file there would be be audio files any effect information , any edits done and all extra information
5. Are session files usually transportable between different systems?
ANSWER: yes , on a hard disk recorder the information is recorded and stored on tp the session file , then that session file be transter to a computer using opical cables , firewire , ethernet , etc
Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
ANSWER: ATA: advanced technology atachment , a connection type used in some current and most older machines to attach the hard disk and most optical drives to the mother board . SCSI :small computer service interface is good for backing up data but not good for recoding and playback . Firewire is a fast connection used commaly for transfering music data from hard disk recorder to a personal computer
6. What is 'fragmentation'?
ANSWER: files get storded in the memory of a personal computer , after time these files start to freagment which means that the files are not just stored in one place in the memory but lots of places around the computer memory , so that is why we deframent our computers
7. Comment on archiving to CD-ROM.
ANSWER archiving to cd rom is backing up your computers data on cd rom . archiving to cd rom is done commanly to free up computer memory and allso incase the computer has a mayger crash and the data is lost . archiving to dvd rom is commanly used lately as the dvd roms have more space for storage
8. What are 'virtual tracks'?
ANSWER: virtual tracks for found on many hard disk recorders and they are a way of allowing more tracks to be recorded for a song .ie. on a channel on a 8 track hard disk recording system you would have 8 virtual tracks which can be recorded on to . so on this 8 track recorder each track would have 8 virtual tracks which you about 64 tracks to record on to , but only 8 tracks can be played back together on once
9. What is meant by 'edit density'? What are the implications of high edit density?
ANSWER:the amount of editing a prossesing in a song track is messured in edit density . ifa tack has a lot of edit density this a cause problems for the CPU causing timing problems
10. Does the editing and trimming of regions delete audio data from the disk?
ANSWER: no it does not delete audio data from the disk it only changes it
11. In editing, what is the difference between 'slip' and 'grid' modes?
ANSWER: in editing if the program is set on grid this means that everthing when moved will snap to the grip so you can not move things any where you want .ie. snap it bar, snap to beet . if the program is set on slip this means that when data is moved it can be moved anywhere it will not snap to anything
12. When might it not be possible to create a crossfade?
ANSWER: cross fading to when 2 audio tracks are mixed together using a fade at the end of one and the start of the other , so that pops or clicks are not heard . cross fading can only be possible to the tracks you wish to cross fade over lap
13. What is 'bouncing', in the context of mixing?
ANSWER:bouching is sub mixing a group of tracks to free up more channels for recording preferibly using vertual tracks
14. What is meant by 'latency'?
ANSWER: latency is usly to do with midi but not all the time . latency is the time it takes for sound to go through the sound card and to heard , dealy is added to our hearing . ie. using a midi keyboard to trigger a soft synth , latency is the time it takes from the time the key is pressed untill the time it is triggered and heard my your ears . latency can be turn off or down a lot on some programs but it still can be annoying if your are recoding something and listening back at the same time , it would put you off
15. What is the difference between DSP processing and host-based processing?
ANSWER: on a DSP based sound card the effects and plugins are built into the card , so you would not need to load them in on your computer . host based processing is when there are not effects of plugins on your sound card , so you do have to load them on to your computer
16. Was DAT originally intended as a professional or a domestic recording medium?
ANSWER DAT was originally intended as a professional recording system
17. What is the sampling rate of standard DAT?
ANSWER: standar DAT sample rares at 44.1 khz or 48.0 khz
18. What is the resolution of standard DAT?
ANSWER: it is up to 114 million bits per square inch
19. What is 'azimuth recording'?
ANSWER: azimuth recording refers to the tilt of the recording head in the plain paralel to the tape. the head gap should be perpendicular to the tape so that all track gaps are electricaly in the phase with each other
20. Describe the head wheel in DAT recorder.
ANSWER: this a rotery haed that is in side a dat recorder , it is used to take in the tape a read or write in information to or from it , it brings the tape down in to the machine and then sends the information on a diaganle angle so more information can fit on the tape , and so that the tape can be played a speed or slowed down
21. What is SCMS?
ANSWER: SCMS: serial copy manigment system , this is a way of stoping digital info being copyed
22. Describe in what conditions a DAT recorder may be capable of near-simultaneous off-tape recording?
ANSWER: for a dat machine to be capable or near-simultaneous off tape recording the machine would require an extra pair of haeds
23. What is the sub-code area of the DAT tape used for?
ANSWER: in dat tapes they have a built on sub-area code is that the machine can find the part of the tape you want , there are 3 sub-area codes on a dat tape , start id , skip id , and program number , it allso can write in simple time code
24. What is 'interleaving'?
ANSWER: this is the rendering of audio files with the left and right audio mixs rendered as a sterio pair
25. What is the width of the tape used for 24-track DASH?
ANSWER: 24 tracks are located across the tape , there are 2 outside anolog tracks and a additional control track located out side
26. What is the width of the tape used for 48-track DASH?
ANSWER: it is the same as a 24 track track excpept with 48 tracks , there are 48 tracks located across the tape , 2 ouside anolog tracks and a additional control track located outside
27. Describe how 24-track and 48-track DASH machines are compatible.
ANSWER: they playback and record as nornal , like any other machine
28. How are DASH tapes edited?
ANSWER: dash tapes are edited using the splice method . when the edit point is found , the tape is cut with a splicer and it is stuck together with special tape
29. In DASH, why does a playback head come before the record head in the tape path?
ANSWER: on a dash machine the playback head comes before the record head bacause digital orperation take a while to happen but anolog pressesing happens straight away.since there is a delay in dash prossesing the signal, when overdubing the delay is avoided if the playback head comes before the record head
30. Comment on the cleaning requirements of DASH
ANSWER:a dash machine should be cleaned by an expert with special tools , and it should not be cleaned with cotton like an anolog tape recorder
31. How many tracks does a modular digital multitrack (MDM) have?
ANSWER: it has 8 tracks on to standerd video tape (SVHS)
32. How can more tracks be obtained?
ANSWER: modular systems can linked together , so that would give us a a max of about 128 tracks
33. Comment on the types of usage of ADAT and DTRS machines?
ANSWER: ADAT alesis digital tape , DTRS digital tape recording sytem allso used from making digital tape copys . both use super VHS video tapes |
|
Mon Oct 10, 2005 9:23 am |
|
|
Kepano
Joined: 06 Jan 2005
Posts: 4
|
|
|
|
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.
Latency times are reduced tremendously. All of the processing goes into the device whatever it may be versus relying on the computers internal processor to conduct the operations. As a result you get a more powerful interface versus one where the computer is forced to have extremely high costly upgrades in order to do the same things.
Disk recorders offer the option of first having the audio come out clear and concise every time vs. tape which degrades over time. Secondly tape recorders are limited to the amount of tape that you have available at any given time. Disk recorders have the problem of storage space but the nice thing is that you can erase and rerecord on the fly. In the case of a tape system you have to rerecord over what was undesirable.
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?
The main limitations by far would be the fact that it wouldn’t be able to do simultaneous recording. This would therefore only allow you to record only single or stereo input instruments. Even then though let’s say you wanted to record multiple mics like a drum set or something. The lack of inputs means that at best you would only be able to record two overheads or maybe one overhead and a kick etc.
4. What information is stored in the session file?
Simply the file paths to where the audio tracks are. For example, in any type of software audio tracks must be imported. As a result, they are imported from different file sources if you’re unorganized and from one central location if you are organized. Whenever you save then the session file keeps track of where everything came from and stores that information for retrieval accordingly. When you open the session file that’s why sometimes it takes awhile for it to load depending on your computer’s speed and processing power.
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 not usually transportable between different systems but the audio data is through Direct X.
The problem with SCSI and Firewire is that they are external systems that must be connected to the system. The problem arises when trying to save something to these devices. Whereas they are fast ATA being that it is internal to begin with is faster in comparison. One may need to have an external device but for professional recording applications this is not recommended. The possibility also exists that it may be easier to steal your work.
6. What is 'fragmentation'?
Fragmentation is when storage space on a disk is broken up into pieces that are spread out all over the disk.
7. Comment on archiving to CD-ROM.
The problem with archiving to CD-ROM is that the audio quality while still good it not as good as a disk system. CD-ROM has 16bit audio quality while hard disk systems have 24bit quality.
8. What are 'virtual tracks'?
Virtual tracks are tracks that are present in a session file but cannot be heard due to the fact that the resources required for playback are being taken up.
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?
No it doesn’t. The only way that data is deleted is at the end of the session when the undo files are flushed and then your edits become a permanent part of the piece.
11. In editing, what is the difference between 'slip' and 'grid' modes?
12. When might it not be possible to create a crossfade?
Whenever songs are in two different keys. If the tracks don’t overlap.
13. What is 'bouncing', in the context of mixing?
Bouncing means that you take a track or a series of tracks and you put them onto another single track space i.e. you take eight drum tracks and turn them into one.
14. What is meant by 'latency'?
Latency is the delay that occurs on the disk. For example, whenever you are monitoring a song you may get latency in the monitoring between recording and listening. The data may not be in real time.
15. What is the difference between DSP processing and host-based processing?
D. S. P. is usually put in after the fact of a recording. Host-based occours during the mixing and recording process.
16. Was DAT originally intended as a professional or a domestic recording medium?
DAT was invented by Sony in 1987 and was originally intended for use in a professional recording situation but became available to the common man as it were in subsequent years.
17. What is the sampling rate of standard DAT?
32 kHz, 44.1 kHz, 48 kHz.
18. What is the resolution of standard DAT?
12 bits (32 kHz) and 16 bits (44.1, 48, 32 kHz)
19. What is 'azimuth recording'?
20. Describe the head wheel in DAT recorder.
It is similar to that of a video cassette recorder that spins at 2,000 rpms
21. What is SCMS?
Pronounced “scums” it is a way of not allowing digital tape to be copied. In other words record labels didn’t want their stuff to get cloned so they invented this to prevent that from happening.
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?
It is used to store information like track number, indexing, and different timing information i.e. elapsed time and time remaining etc.
24. What is 'interleaving'?
Interleaving is when the data of a recording is saved over a wider space on the storage media thus cutting down on consecutive errors in the data. In a DAT the right head will record the left heads odd signals and vice-versa.
25. What is the width of the tape used for 24-track DASH?
½ inch tape to 1 inch tape
26. What is the width of the tape used for 48-track DASH?
½ inch tape to 1 inch tape
27. Describe how 24-track and 48-track DASH machines are compatible.
They were compatible in that they used the same type of tape.
28. How are DASH tapes edited?
They are quite literally cut and pasted with scissors and analog tape.
29. In DASH, why does a playback head come before the record head in the tape path?
Digital heads aren’t able to record and playback simultaneously. It was engineered in such a way that Audio could be overdubbed and one could still monitor what had already been recorded.
30. Comment on the cleaning requirements of DASH
DASH like any other machine that uses heas required a highly trained professional to clean the heads. The solutions needed consisted of 99% ammonia with a lint free cloth. Cleaning is done by hand.
31. How many tracks does a modular digital multitrack (MDM) have?
8 tracks at 16 bit
32. How can more tracks be obtained?
It is possible to link machines together in order to get more tracks out of them.
33. Comment on the types of usage of ADAT and DTRS machines?
ADAT is used in studios to provide a way of digital recording that is of very high fidelity. It is used primarily for audio. DTRS has found it’s way into broadcast and TV due to its built in timecode.
http://www.motu.com
http://web.ask.com/web?o=0&qsrc=19&q=What+is+disk+fragmentation%3F |
|
Tue Oct 11, 2005 11:19 pm |
|
|
|
|
AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
|
| editing |
|
|
Good stuff everyone.
Kepano, did you find this ok?
11. In editing, what is the difference between 'slip' and 'grid' modes?
_________________
It's all in the ears. - Learn the concepts not the software.
Audio Courses is a way into the music business for you
|
|
Sun Oct 30, 2005 2:21 pm |
|
|
|
|
All times are GMT. The time now is Fri May 16, 2008 4:05 pm
|
|
|
|
| |
