AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Week 9 - MIDI and Recording |
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Here are your questions. Some repeats, and certainly all are taken from past exam papers. It is in your interest to research and find out the answers. Looking forward to reading as the week progresses.
Good luck.
1. Describe the following equipment used by a DJ: Cartridge and stylus, Pickup arm, Turntables, Mixer.
2. Why cannot the output of the cartridge be connected directly to a mixing console?
3. Why is it convenient to DI a synthesizer?
4. Comment on the stereo output of many synthesizers?
5. Why might it be desirable to amplify and mic up a synthesizer, as you would an electric guitar?
6. Comment on the use of loops in recording.
7. Comment on tape loops.
8. Comment on looping using a sampler and sequencer.
9. Why is the sample looped using the sequencer in preference to looping it in the sampler?
10. Comment on the significance of synchronizing the sequencer to multitrack tape.
11. Comment on the suitability of audio sequencers for sample looping.
12. What is timecode?
13. Comment on LTC, VITC and MTC.
14. Comment on MIDI Clock.
15. Why is it desirable to synchronize two MIDI units via MIDI Clock?
16. How does MTC correspond to MIDI Clocks and Song Position Pointers?
17. Why is it desirable to synchronize a sequencer to multitrack tape?
18. Comment on the two stages of building up a recording on multitrack tape with the aid of a sequencer.
19. What is an audio sequencer?
20. Is an audio sequencer suitable as a replacement for a multitrack tape recorder (analog or digital)?
21. Comment on the suitability of an audio sequencer for sample and loop editing?
22. Why is it not straightforward to synchronize an audio sequencer to multitrack tape?
23. What parameters of effects can often be controlled via MIDI?
24. Why would you want to control effects parameters by MIDI?
25. Does MTC come in all the frame rates of SMPTE/EBU timecode?
26. Does MTC contain an address?
27. Does MTC contain a clock?
28. Is MTC useful for synchronizing a MIDI sequencer?
29. Is MTC useful for synchronizing digital audio?
30. Is MTC useful for synchronizing analogue audio?
31. Comment on the difference between standalone hard disk recorders and computer based hard disk recorders.
32. Why is it a problem to use hard disks for long term storage?
33. Onto what media does backup/archival storage take place?
34. What are the advantages of standalone hard disk recorders (compared to tape) for editing?
35. What are the advantages and disadvantages of computer based hard disk recorders compared to standalone hard disk recorders?
36. Comment on the use of Pro Tools as an accessory to multitrack tape.
37. List the common digital multitrack tape formats and describe their characteristics.
38. What is 'formatting'?
39. What are the advantages and disadvantages of digital multitrack compared to analogue multitrack?
40. Compare the maintenance and cleaning of an analogue recorder to that of a digital recorder?
41. Who carries out routine maintenance?
42. Describe how the heads and guides of an analogue machine are cleaned. Mention the materials used.
43. Describe how the pinch roller of an analogue machine is cleaned. Mention the materials used.
44. What are the effects of neglecting cleaning?
45. Why must an analogue machine be periodically demagnetised?
46. What happens if a machine is never demagnetised?
47. What might happen if the demagnetised is operated incorrectly?
48. Why do analogue tape recorders need to be lined up?
49. Do digital recorders ever need to be lined up?
50. Comment on the three elements of line up.
51. Explain the need for monitoring in sync.
52. Why is the sync signal inferior to the playback signal?
53. Why does this matter in track bouncing?
54. Is it possible to edit 2" analogue tape?
55. Is it possible to synchronise two 24-track recorders?
56. 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?
57. Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
58. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
59. How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
60. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
61. What information is stored in the session file?
62. Are session files usually transportable between different systems?
63. Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
64. What is 'fragmentation'?
65. Comment on archiving to CD-ROM.
66. What are 'virtual tracks'?
67. What is meant by 'edit density'? What are the implications of high edit density?
68. Does the editing and trimming of regions delete audio data from the disk?
69. In editing, what is the difference between 'slip' and 'grid' modes?
70. When might it not be possible to create a crossfade?
71. What is 'bouncing', in the context of mixing?
72. What is meant by 'latency'? What is the difference between DSP processing and host-based processing? |
Sun Jan 12, 2003 9:38 pm |
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Dani
Joined: 28 Jan 2003
Posts: 35
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1. Describe the following equipment used by a DJ: Cartridge and stylus, Pickup arm, Turntables, Mixer.
Cartridge: Holds the stylus.
Stylus: Diamond headed, reads the grooves on the record and transfers the vibrations into the cartridge which converts them into electricity.
Pickup Arm: Holds the cartridge and moves feely to track the groove.
Turntable: Hold the record and spins it at the correct speed, can be fine tuned to match tempo's.
Mixer: Provides a method af taking the signal from multiple decks (usually two) and changing the volume so that you get either a good fade in/out or an imediate change.
2. Why cannot the output of the cartridge be connected directly to a mixing console?
Because it's too quite and needs also to be converted to get around RIAA equalisation.
3. Why is it convenient to DI a synthesizer?
Because the output is at a decent level and does not need to go through a DI box.
4. Comment on the stereo output of many synthesizers?
The majority of modern snthesizers not only have stereo outs but also have assignable outs as well. This mean they can send an audio signal to any one of up to 8 individual outputs. This is usefull if you want to eq and mix synth tracks independantly, but don't want to commit them to your medium untill mix down.
5. Why might it be desirable to amplify and mic up a synthesizer, as you would an electric guitar?
Perhaps you want the sound of a keyboard amp/cab, or you want a little bit of natural ambience on your recording.
6. Comment on the use of loops in recording.
Loops are usfull for drums and instrument riffs which are too difficult or time consuming to produce yourself. Also, using loops takes up less resources when recording, i.e. Tracks on a multitrack or hard drive space on a DAW.
7. Comment on tape loops.
Tape loops are samples of sound that are cut and spliced together to create something new. Sometimes silence is splicede into a sound to create rythmic properties.
8. Comment on looping using a sampler and sequencer.
When you loop a sample in a sampler you have to set a start and finishe point for the loop, this has to be exact or the loop will go out of sync with the sequencer over a period of time. Looping with a sequencer is much easier, for one thing, you don't have to loop the sample itself, you just have to re-trigger the sample at the begining of each bar. This keeps it in sync. Obviously you have to match the tempo of the song to the loop, or, with time stretch, match the loop to the tempo.
9. Why is the sample looped using the sequencer in preference to looping it in the sampler?
See above.
10. Comment on the significance of synchronizing the sequencer to multitrack tape.
When a sequencer is synced to a tape machine, it gives the artist more flexibility with MIDI, for example, half way through the third verse, the artist wants to add a nother 8 bars of music. he can add the extra MIDI inforamtion without having to re-record anything of the sysnths/MIDI drums on tape. The artist can change any of the MIDI all the way up to final mixdown. This also leaves more tracks free for other instruments/vocals/effects.
11. Comment on the suitability of audio sequencers for sample looping.
Audio sequencers make good sample looping devices, it is very easy to copy and paste audio information using modern day recording software. It also gives you extra control over the loops as every four bars you could have an eq change or effects process.
12. What is timecode
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Timecode is a syncronization method to enable MIDI devices and audio recording devices to play together.
13. Comment on LTC, VITC and MTC.
14. Comment on MIDI Clock.
MIDI clock is a simple sync method that gives out a sync signal at a resolution of 24/per quarter. It does not, however carry any song position pointer information.
15. Why is it desirable to synchronize two MIDI units via MIDI Clock?
Perhaps you want to use the arppegiator on a synth and sync it to a sequencer on another machine. Song position wouldn't matter as an arppegiator loops itself anyway and is triggered by keypresses. In some cases the actual MIDI information that the arppegiator produces is recordable, freeing up the arppegiator for more tracks to use.
16. How does MTC correspond to MIDI Clocks and Song Position Pointers?
MTC can work with both MIDI Clock and Song Position Pointer information. It lets you start a song or sequence at any point and the rest of the synced equipment will catch up.
17. Why is it desirable to synchronize a sequencer to multitrack tape?
When a sequencer is synced to a tape machine, it gives the artist more flexibility with MIDI, for example, half way through the third verse, the artist wants to add a nother 8 bars of music. he can add the extra MIDI inforamtion without having to re-record anything of the sysnths/MIDI drums on tape. The artist can change any of the MIDI all the way up to final mixdown. This also leaves more tracks free for other instruments/vocals/effects
18. Comment on the two stages of building up a recording on multitrack tape with the aid of a sequencer.
Firstly you record your MIDI data into the sequencer, you then have the facility to change edit any part of the music non-destructivly. (you can back up a MIDI track and re-instate it if your edit doesn'r sound right).
When you are happy with your MIDI information you can then, if so desired, record the sounds onto the multitrack. You can also wait until mixdown before commiting the MIDI and use control changes to change any levels throughout the song. This is especially good if you haven't got an automated desk and the synths require a lot of mix changes.
19. What is an audio sequencer?
An audio sequencer works like a tape recorder with the added advantage of being able to copy and paste audio information and make loops, reverse sounds and use processes on them before mastering.
20. Is an audio sequencer suitable as a replacement for a multitrack tape recorder (analog or digital)?
In my own humble opinion, yes, in fact I think audio sequencers have an added flexiblilty that tape recorders simply don't have. Why spend time with a knife and splicing tape when you can use ctrl c/ctrl v and get the same effect.
21. Comment on the suitability of an audio sequencer for sample and loop editing?
Audio sequencers make good sample and loop editing devices because of their graphic nature, it's easier to edit a sound you can see, especially if you zoom into the waveform.
22. Why is it not straightforward to synchronize an audio sequencer to multitrack tape?
Because each system really wants to be the master in a setup. Multitrack tapes, once striped have no way of reacting to tempo changes sent to it from an audio sequencer, so it can't adjust. Which leaves the multitrack being the best bet for being the master, but of course, you can't program tempo changes on to a tape by itself, you need to have a master machine pumping out the code. It's a bit like a catch 22 situation.
23. What parameters of effects can often be controlled via MIDI?
Not sure if that should read "parameter OF" or "parameter OR". So I'll go for the first one.
In some cases you can change actual effect settings using control change information, such as decay time on a reverb or delay time on a delay. Even if you can't do that you can change effects patches or bypass the unit completly.
24. Why would you want to control effects parameters by MIDI?
Because it can be a usefull creative tool in the studio to syncronize effects to the tempo/beat of a song. You can change a reverb on a snare between bars for instance. That sounds great. Also, it takes some of the pressure off the enginner if a lot of effects changes have to take place.
25. Does MTC come in all the frame rates of SMPTE/EBU timecode?
Don't know.
26. Does MTC contain an address?
No
27. Does MTC contain a clock?
Yes
28. Is MTC useful for synchronizing a MIDI sequencer?
Yes
29. Is MTC useful for synchronizing digital audio?
Yes
30. Is MTC useful for synchronizing analogue audio?
No
31. Comment on the difference between standalone hard disk recorders and computer based hard disk recorders.
Hard disk recorders are purpose made for the job, they have good signal to noise ratios and can record on all tracks at once. Computer based systems are general purpose and normally not designed internally with digital audio in mind. Expensive hardware has to be added to enable computers to record multiple tracks, (in standard form a PC can only record a two tracks at once, usually in stereo interleaved format). Hardware limitations asside, PC based systems offer greater flexiblity with recording software, Virtual Instruments and software plugins/effects. The other advantage (if you see it as an advantage) is you can master directly to CD when you are finished, which removes the risk of getting the signal "dirty" when you output to another mastering medium.
32. Why is it a problem to use hard disks for long term storage?
Because there is a risk of disk damage/corruption.
33. Onto what media does backup/archival storage take place?
ZIP Drives, CDR's, DVDR's and Tape drives.
34. What are the advantages of standalone hard disk recorders (compared to tape) for editing?
You can move, copy, delete information without having to get your knife out.
35. What are the advantages and disadvantages of computer based hard disk recorders compared to standalone hard disk recorders?
Answer to question 31
36. Comment on the use of Pro Tools as an accessory to multitrack tape.
With Pro Tools synced to a multitrack you can add MIDI, loops and even use pro tools to record some of the audio and copy it to other locations in the song.
37. List the common digital multitrack tape formats and describe their characteristics.
DAT Digital Audio Tape, small cassette like media. Similar in operation to a video recorder. 16bit 48k
DASH Digital Audio Stationary Head. 24 Track. Uses reel to reel tapes which are inexpensive. The quality will not diminish over time.
ADAT Alesis Digital Audio Tape. Uses Video tape as a medium, capable of 8 tracks. Tapes need to be formatted before use. More machines can be synced to provide more tracks.
HDR Hard Disk Recording. Uses a computer hard drive to store audio data. The use of dedicated hardware raises the number of audio tracks that can be used. When a recording is finished the audio files can be written to a CD ROM for later use.
38. What is 'formatting'?
Formatting is the process of wiping a digital medium and preparing it for use in a particular system.
39. What are the advantages and disadvantages of digital multitrack compared to analogue multitrack?
Advantages: Low SNR, No loss copying. Bigger headroom before distortion.
Disadvanatges: No warmth, expensive, many formats offer less tracks to record on.
40. Compare the maintenance and cleaning of an analogue recorder to that of a digital recorder?
Not known
41. Who carries out routine maintenance?
Engineer
42. Describe how the heads and guides of an analogue machine are cleaned. Mention the materials used.
Cotton bud or equivelent and isopropyl alchohol.
43. Describe how the pinch roller of an analogue machine is cleaned. Mention the materials used.
Cottin bud and rubber cleaning solution. (make sure you don't get any on the plastic parts!)
44. What are the effects of neglecting cleaning?
Poor recording/playback quality, loss of top end frequencies and problems if you are having to go back to an old tape and put on overdubs. The new tracks will sound different.
45. Why must an analogue machine be periodically demagnetised?
Because the head picks up magnetic particles which affect the tape and recording.
46. What happens if a machine is never demagnetised?
The heavily magnetised parts will affect the magnetic part on the tape and couse it to erase.
47. What might happen if the demagnetised is operated incorrectly?
It could have the reverse effect and actually magnetise the head more.
48. Why do analogue tape recorders need to be lined up?
To set the level of the bias signal and because if they are not you get a reduction in quality and a boost in noise.
49. Do digital recorders ever need to be lined up?
I don't think so.
50. Comment on the three elements of line up.
Azimuth
BIAS
and EQ
51. Explain the need for monitoring in sync.
So the musician can hear when to play, to get the timing right. If the musician was to listen to normal playback, he would play slightly behind.
52. Why is the sync signal inferior to the playback signal?
Because it comes from the record head and not the playback head.
53. Why does this matter in track bouncing?
Because you need to bounce from the record head, or the tracks that aren't being bounced will be out of sync.
54. Is it possible to edit 2" analogue tape?
Yes it is, but it would be better to digitise it and edit on a computer.
55. Is it possible to synchronise two 24-track recorders?
Not sure, it sounds inherently difficult. How would the slave recorder alter it speed to catch up or slow down.
56. 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?
Because an integrated disk system has only one job to do and that is record. PC's have a million other things running on them and as a result THEY CRASH!!!!
57. Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
Not sure I understand the question
58. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
24
59. How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
24, ideally.
6
0. If a disk recording system had two inputs, two outputs, and was capable of twenty-four tracks, what would be its main limitations?
Multitrack recording would not be possible.
Drums would have to be mixed to 2 tracks at the recording phase.
61. What information is stored in the session file?
The Session File is basically the instruction manual for Pro Tools. It contains all the information Pro Tools uses to re-construct your session, i.e.
where audio files are located and on which tracks
which edits and fades you've created, etc.
The Session File does not actually contain audio itself. It acts as a virtual traffic director, instructing the computer where to find everything it needs for a given session.
62. Are session files usually transportable between different systems
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No.
63. Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
SCSI, very fast medium, but expensive. ATA 133 is a good fast cheap medium. Never used Firewire but the new Serial ATA standard (which I've just got, hehe) offers 150mb a second transfer rate, woohoo.
64. What is 'fragmentation'?
Fragmentaion occurs when information is saved to a hard drive non sequencially, it speads the information over many different sectors and as a result reads more slowly as it can't stream the data off the hard drive as fast.
65. Comment on archiving to CD-ROM.
CD ROMS are good for saving wavs for backup, they can hold up to 80 mins of audio. Save as wavs though and not Red Book Audio (audio cd). Because you can keep the bit rate higher than if it was audio. You can also save any other track specific data for later use or even to take to another studio. DVD would be a better format for backup as they can hold 4.7GB.
66. What are 'virtual tracks'?
Before the advent of affordable digital tape and budget hard disk recording systems, MIDI virtual tracks were a great way to make high-quality recordings. If you had MIDI tone generators, some signal processors, and a mixer, you could compose in a sequencer, send the data to the MIDI gear, and mix down in real time to DAT or analog tape. The name "virtual tracks" came about because the various MIDI sounds acted like tape tracks and were mixed down like tape tracks, but weren't tape tracks -- the audio was derived by playing back data recorded in a sequencer through a tone generator, in real time.
67. What is meant by 'edit density'? What are the implications of high edit density?
Edit density - the more the audio is edited and scattered, then the more the hard disk drive has to search for each segment. The harder it has to work, the slower it will retrieve the audio.
68. Does the editing and trimming of regions delete audio data from the disk
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Not usualy, it just tells the software "just play back this peice of data".
69. In editing, what is the difference between 'slip' and 'grid' modes?
Slip enables you to move the audio data freely, grid mode aligns the start points to a grid. The grid can be chosen by the user.
70. When might it not be possible to create a crossfade?
71. What is 'bouncing', in the context of mixing?
Recording previously recorded tracks on to a vacant track to free up tracks for further recording.
72. What is meant by 'latency'? What is the difference between DSP processing and host-based processing?
Latency is the time difference between what you play and what you hear.
DSP usually means there is hardware on the device that handles the effects in real time, like an outboard effects processor, host based means it's being done by the software. DSP is better. |
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Wed Apr 30, 2003 6:06 pm |
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resol69
Joined: 31 Dec 2002
Posts: 69
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| Nancy's thoughts |
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http://www.indiana.edu/~emusic/MIDI.html
http://www.philrees.co.uk/articles/timecode.htm
http://www.audiomasterclass.com/library/recordingtechniques/4midiandmultitrack.html
http://www.loopers-delight.com/tips/tape/tape_looping.html
http://arts.ucsc.edu/ems/music/equipment/analog_recorders/Analog_Recorders.html
http://www.united-trackers.org/resources/sampling/external.htm
1.Describe the following equipment used by a DJ: Cartridge and stylus, Pickup arm, Turntables, Mixer.
The Cartridge is at the end of the arm and holds the stylus. The stylus is the needle that reads the music in the groove of a record. The pick up arm carries the cartridge and stylus across the record. The turntable is the base that rotates the record. The turntable is hooked up to a mixer so the DJ can add effects and mix songs together. A DJ mixer is distinctly different to any other type of mixing console. It is split into two sets of inputs with a cross fader in between. Obviously the idea is to fade between two records, but the cross fader will fade between any pair of inputs on opposite sides of the mixer. There are all sorts of mixers at all levels of quality. The thing you want to avoid most is a noisy crossfader so ask the supplier whether the cross fader can easily be replaced when necessary.
2. Why cannot the output of the cartridge be connected directly to a mixing console?
The output level is around 5 mV, much lower than line level around 0.775 V The required input impedance for a cartridge input is 47 kiloohm. The input impedance of a mic input is around 2 kohm - too low for the cartridge To achieve a satisfactory duration on a record, RIAA EQ is used in the cutting process which reduces LF and therefore the maximum excursion of the groove. This is compensated by reverse RIAA EQ in the cartridge input stage. Normal mic and line inputs do not have this.
3. Why is it convenient to DI a synthesizer?
You don’t have to send the output to amplifer and then mic the amp.
4. Comment on the stereo output of many synthesizers?
Most synths I’ve read about online have more than one set of stereo outputs.
5. Why might it be desirable to amplify and mic up a synthesizer, as you would an electric guitar?
You may want to include the sound of the room in the recording. Send a composite synthesizer mix through loudspeakers into a studio or room, and then mic the room to add early reflections to the synthesizer tracks. I might also add reverb, being careful to make sure there is enough pre-delay in the reverb program to allow those early room reflections to be heard.
6. Comment on the use of loops in recording.
Loops are used a lot for drums, especially in dance music. It’s important to use different loops, though, so the music isn’t boring. A human drummer would not repeat the same four bars during the entire song.
7. Comment on tape loops.
Making a tape loop is simple; you merely splice the end of a piece of tape to its beginning. It is the playing of a loop that is sometimes tricky. The tape must be kept in the proper relationship to the heads and cutoff sensor without benefit of the takeup or supply reels. You have to modify the recorder to keep playing the loop.
8. Comment on looping using a sampler and sequencer.
You can create a sample and then run it through a sequencer to create a loop. The sequencer acts a tape recorder and player. You can program the sequencer to repeat the loop.
9. Why is the sample looped using the sequencer in preference to looping it in the sampler?
Looping in the sampler will allow you to hear it in the rest of the mix. You make take a while to get a loop just the way you like in the sampler, but when you ,mix in the other tracks, you may have to make changes.
10. Comment on the significance of synchronizing the sequencer to multitrack tape.
Synthesizers don't replace the need for recording live parts onto audio tape on occasion. If you are a songwriter, you will want to record lead and background vocals. Almost any type of music benefits from the addition of some "real" instruments or voices. The wonderful thing about working with MIDI sequencers and multitrack tape is that the synthesizer parts never have to be recorded to the tape. MIDI sequencers and tape can be synchronized together, so MIDI parts are in the sequencer and acoustic parts are on multitrack tape, both working together as one. When finished, the whole piece can be mixed and recorded to a stereo master tape.
Most sequencers, computer MIDI interfaces, and drum machines have built-in sync to tape. Tape sync is a special audio signal created by a MIDI device that is recorded onto one track of the multitrack tape and then played back into the device. It's simple to use. The sequencer can record or playback while locked to the sync signal tape.
All sequencers and drum machines have special timing clocks that maintain the tempo to which you set them. Tape sync converts this clock into tones that are recorded onto tape. The sync signal is usually labeled sync out or tape out on most devices.
11. Comment on the suitability of audio sequencers for sample looping.
You may want to loop in the sequencer since you can load information into the sequencer in real time (the speed at which the musician is able to perform the music) or in step time (one note at a time). Information entered stepwise can later be replayed in real time by simply pressing a button.
Also if you try to use the looping feature in the sampler, All those little timing differences in the computer, sampler, software and the loop itself become very apparent if you try to use the looping feature in the sampler to do the loop. You always retrigger the loop every two to four bars with a new note on the down beat so that it stays in sync with your track.
But then again I’ve read articles that say you SHOULD loop in the sampler, so I guess it’s your personal preference.
12. What is timecode?
Until the advent of video recording, there was mechanical sound to film synchronisation. This mainly relied on sprockets (a row of neat holes) in the film and in special sprocketed recording tape. Relative timing adjustments could be made by slipping sprocket holes. The same sprocket holes were used to maintain synchronisation. Video tape hasn't got any sprocket holes, so when video arrived an electronic equivalent was needed to take the place of mechanical methods of synchronisation.
In 1967, The US Society of Motion Picture and Television Engineers introduced that which we call SMPTE ("simpty") time code. The timing data in SMPTE takes the form of an eight digit twenty-four hour clock. The count consists of 0 to 59 seconds, 0 to 59 minutes and 0 to 23 hours. The second is subdivided into a number of frames, which may be varied to match the various frame-rates used around the world. The frame-rate is the number of times a second that the picture is updated so as to give the illusion of continuous movement.
13. Comment on LTC, VITC and MTC.
LTC is Longitudinal Time Code or Audio SMPTE. It is recorded onto the audio track of a video tape or onto an audio tape.
VITC is vertical-interval time code or SMPTE for video.
When principle photography is on videotape, the time code can either be applied at the time of shooting, or added later in the production house. For several reasons, the preferred method is to record the time code during photography. When applied during principle production, the time code can be applied to certain physical regions of the videotape that are not available for such use at any later stage of production. These "regions" are within the tape area used by either the control signals or the picture itself. When the time code is recorded onto the picture area of the videotape, it is applied to an area known as the vertical interval.
The most obvious advantage to what is commonly referred to as "address track" time code is its effect on sound recording. When the time code is embedded within video and control signals, both audio tracks are available for sound. If the time code is added to the tape after photography, it must be "striped" onto one of the audio channels. Not only does this eliminate the availability of one audio track, but it also presents the possiblity of degrading the quality of sound on the remaining channel.
MIDI Time Code (MTC). The MTC protocol attempts to bridge the gap between MIDI Clock timing, which uses the relative time measurement of note value and tempo, and SMPTE, which uses absolute values of hour::minute::second::frame. MTC enables a sequencer, dealing in relative musical values, to synchronize with videotape or multi-track audio tape with recorded SMPTE information
14. Comment on MIDI Clock.
Some master device that controls sequence playback sends this timing message to keep a slave device in sync with the master. A MIDI Clock message is sent at regular intervals (based upon the master's Tempo) in order to accomplish this.
There are 24 MIDI Clocks in every quarter note. (12 MIDI Clocks in an eighth note, 6 MIDI Clocks in a 16th, etc). Therefore, when a slave device counts down the receipt of 24 MIDI Clock messages, it knows that one quarter note has passed. When the slave counts off another 24 MIDI Clock messages, it knows that another quarter note has passed. Etc. Of course, the rate that the master sends these messages is based upon the master's tempo. For example, for a tempo of 120 BPM (ie, there are 120 quarter notes in every minute), the master sends a MIDI clock every 20833 microseconds. (ie, There are 1,000,000 microseconds in a second. Therefore, there are 60,000,000 microseconds in a minute. At a tempo of 120 BPM, there are 120 quarter notes per minute. There are 24 MIDI clocks in each quarter note. Therefore, there should be 24 * 120 MIDI Clocks per minute. So, each MIDI Clock is sent at a rate of 60,000,000/(24 * 120) microseconds).
15. Why is it desirable to synchronize two MIDI units via MIDI Clock?
So they stop and start playback at the same time. A slave device might receive (from a master device) a Song Select message to cue a specific song to play (out of several songs), a Song Position Pointer message to cue that song to start on a particular beat, a MIDI Continue in order to start playback from that beat, periodic MIDI Clocks in order to keep the playback in sync with the master, and eventually a MIDI Stop to halt playback.
16. How does MTC correspond to MIDI Clocks and Song Position Pointers?
MTC and Midi Clock are related but actually intended for different purposes. Midi clock came first and its principle role is to tell listening midi devices what the tempo is(primarily sequencers and drum machines). Midi Song Pointer came next and it tells other midi devices where bar 1 is, where bar 2 is, etc. As you can imagine, a high degree of accuracy (we're talking milliseconds here) is needed for consistent control and lockup between video decks, audio machines and midi equipment running together. Midi Time Code(MTC) was developed to give midi devices an absolute reference point, much finer than bars or beats. Midi machine control(MMC) allows the sequencer to chase the audio recorder OR for the audio recorder to chase the sequencer! Midi Machine Control uses MTC to keep things locked up to a very tight degree of resolution.
17. Why is it desirable to synchronize a sequencer to multitrack tape?
Suppose you have a sampler or multitimbral synth with eight voices, together with a sequencer to drive it. This means that you have the possibility of having eight different sounds on the go at any one time. Add an eight track recorder, which becomes limited to seven tracks due to the necessity for a sync track, then if you wish you can have all eight voices simultaneously sounding on all seven available tape tracks. 8 + 8 + 8 + 8 + 8 + 8 + 8 = 56 voices. See what I mean? And if you could sync up the sequencer to the tape with an extra eight voices for the final mixdown, then you would have a grand total of 64 possible different sounds playing at the same time - all originally from the one instrument.
Using a multitrack recorder, even the most basic four-track cassette studio, gives more power to any MIDI system. In addition to recording voices or other instruments, you can also synchronize and overdub your synthesizers onto tape, which effectively gives you the sound of many more instruments than you actually have. If there are more parts in your music than you have instruments available, a few parts can be recorded at a time on each track of the tape machine by synchronizing the sequencer. You can also take advantage of layering several instruments onto a track of the tape for a single part to get a bigger, lusher sound.
18. Comment on the two stages of building up a recording on multitrack tape with the aid of a sequencer
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First, since the tape is completely blank, you'll need to stripe it with some timecode. Striping simply means recording thirty or so minutes worth of timecode all the way along the tape on the highest numbered track - 8, 16 or 24. Then you need to separate the tracks on the sequencer and record each track on the mulitrack. When the tape has no free tracks left, it is still possible to record extra lines into the sequencer, as many as you have MIDI instruments and free channels on your mixer. These will be played 'live' by the sequencer during mix down to stereo.
19. What is an audio sequencer?
Software or hardware designed to record, play and edit music using MIDI and/or audio.
20. Is an audio sequencer suitable as a replacement for a multitrack tape recorder (analog or digital)?
It could, if that’s the kind of sound you are looking for. Used with samplers and synthesisers, a sequencer can complement or replace a multitrack recorder. I prefer live drum sounds though.
21. Comment on the suitability of an audio sequencer for sample and loop editing?
It sounds nifty because you can edit while you are playing since editing is done in real time.
22. Why is it not straightforward to synchronize an audio sequencer to multitrack tape?
You have to get timecode on the tape before you can synchonize. The problem you will have is that when you are striping timecode onto the multitrack tape you will need to control the level, yet many timecode generators have no output level control. You can either temporarily go through the mixer to stripe timecode then disconnect the generator, or buy a generator with an output level control.
23. What parameters of effects can often be controlled via MIDI?
Yyou can control effects, pan, mod, aftertouch, cut off,
pitch, resonance, volume, volume of MIX out and LFO.
24. Why would you want to control effects parameters by MIDI?
To program effects changes during the song?
25. Does MTC come in all the frame rates of SMPTE/EBU timecode?
I think you need a converter. The Philip Rees TS1 MIDI Tape Sync Unit
can generate all four SMPTE frame rate formats. By using a little pushbutton or special MIDI commands, any SMPTE start time can be selected.
There are four standard frame-rate formats: The SMPTE frame-rate of thirty frames per second (fps) is often used for audio in AmericaThe American colour television standard has a slightly different frame-rate of about 29.97 fps. This is accommodated by the SMPTE format known as thirty Drop Frame and is required for video work in America, Japan and generally the 60 Hz (mains frequency), NTSC (television standard) world. The number of frames in each second is not an integer, so an approximation is used; it is based on 30 fps, but two frames counts are dropped (skipped) at the start of every minute, except for every tenth minute. The EBU (European Broadcasting Union) standard of 25 fps is used throughout Europe, Australia and wherever the mains frequency is 50 Hz and the colour TV system is PAL or SECAM. The remaining rate of 24 fps is required for film work, it is rarely used for audio.
26. Does MTC contain an address?
Yes, As with all digital electronic systems, the information in a SMPTE timecode signal is held in binary (base two) format. Within the SMPTE LTC word the numbers of the SMPTE timecode frame address are in binary coded decimal representation.
27. Does MTC contain a clock?
Yes, MTC carries timing information in hours, minutes, seconds, and, frames.
28. Is MTC useful for synchronizing a MIDI sequencer?
Yes
29. Is MTC useful for synchronizing digital audio?
Yes
30. Is MTC useful for synchronizing analogue audio?
Yes
31. Comment on the difference between standalone hard disk recorders and computer based hard disk recorders.
Standalone hard disk recorders don’t have to be hooked up to your computer. A computer based hard disk recorder has to be compatible with your computer and its operating system.
32. Why is it a problem to use hard disks for long term storage?
Because they can be unstable. If your computer crashes and you didn’t back up on an external disk, you could lose everything.
33. Onto what media does backup/archival storage take place?
CD-Rom, Zip, Jazz, floppy, tape.
34. What are the advantages of standalone hard disk recorders (compared to tape) for editing?
It is non-destructive, you don’t have to cut the tape. You can see the music you are editing on screen. You can undo any changes. You can easily make different versions of the mix.
35. What are the advantages and disadvantages of computer based hard disk recorders compared to standalone hard disk recorders?
Hard disk recorders don’t use up your computer’s memory, but at limited to their on-board memory, or external media like a smart card or disk. Software disk recorders may use more of the computer’s memory and the CPU. However, since the music is already in your computer, it may be easier to load the music into an editing program.
36. Comment on the use of Pro Tools as an accessory to multitrack tape.
Pro Tools can be used as an editing and mastering tool for multitrack tape. You can make non-destructive changes and keep the original recording on tape. If you don’t like your edit, you can just start over.
37. List the common digital multitrack tape formats and describe their characteristics.
DAT: Since DAT was intended to be a consumer product right from the start, the cassette housing is very small, 73 x 54 mm and just 10.5 mm thick.
DASH: DASH stands for Digital Audio Stationery Head. The DASH specifications include matters such as the size of the tape, the tape speed and the layout of the tracks on the tape; also the modulation method and error correction strategy, among other things. The format is based on two tape widths: 1/4” (6.3 mm) and 1/2” (12.55 mm). For each tape width there are two track geometries, Normal Density and Double Density and there are also three tape speeds, nominally Slow, Medium and Fast
MDM (ADAT): large cartridge (like VHS) with 8 tracks. Machines can be synchinized to give you more tracks. The original modular digital multitrack was the Alesis ADAT.
38. What is 'formatting'?
Preparing a disk to be used with a certain operating system and program.
39. What are the advantages and disadvantages of digital multitrack compared to analogue multitrack?
Digital multitrack has a signal to noise ratio and distortion performance. Also, when a tape was copied, from an analog tape, the quality would deteriorate significantly. And often there were several generations of copies between original master and final product. Digital audio can be copied identically as many times as necessary. (supposedly, but I’ve seen corrupt digital copies). Digital mulittracks offer more features for their price. However, Digital recorders do not sound better than analog mulittracks. (in my humble opinion).
40. Compare the maintenance and cleaning of an analogue recorder to that of a digital recorder?
You can just put a cleaning disk into a digital recorder to clean the heads, that has to be done manually on an analogue recorder. The inputs and outputs of a digital recorder have to be cleaned manually, though. If you’re getting a lot of static, you can try cleaning the inputs and outputs.
41. Who carries out routine maintenance?
The engineer, or a specialized technician.
42. Describe how the heads and guides of an analogue machine are cleaned. Mention the materials used.
They are cleaned with a cotton swab and isopropyl alcohol.
43. Describe how the pinch roller of an analogue machine is cleaned. Mention the materials used.
The pinch wheel is made of a rubbery plastic. In theory it shouldn't be cleaned with isopropyl alcohol, but it often is. You can buy special rubber cleaner from pro audio dealers but in fact you can use a mild abrasive household liquid cleaner. Just one tiny drop is enough.
44. What are the effects of neglecting cleaning?
In order to get a good recording, the tape must be in very intimate contact with the heads. The wavelength of a 15khz tone recorded at 15 ips is one thousandth of an inch, so a separation of half that amount can be expected to cause some loss of signal. This is not much thicker than a fingerprint. You can not expect good results unless the heads are clean.
45. Why must an analogue machine be periodically demagnetised?
Magnetism will build up if you don’t.
46. What happens if a machine is never demagnetised?
So much magnetism ca build up, it can erase the tape.
47. What might happen if the demagnetised is operated incorrectly?
You can make the magnetism build up worse.
48. Why do analogue tape recorders need to be lined up?
Line up, or alignment, has two functions - one is to get the best out of the machine and the tape; the other is to make sure that a tape played on one recorder will play properly on any other recorder.
49. Do digital recorders ever need to be lined up?
You need to make sure you’re recording/playing to the correct sample/bit rate.
50. Comment on the three elements of line up.
Azimuth - the heads need to be absolutely vertical with respect to the tape otherwise the will be cancellation at HF. The other adjustments of the head - zenith, wrap and height are not so critical and therefore do not need to be checked so often. You need an oscilloscope to see the azimuth angle to adjust it.
The items below are adjusted by using pots on the tape machine while you play an the alignment tape. There is a set of pots for each track. If you have 24 tracks, you have to run through this 24 times. I’ve only had to do this on a two-track machine.
Bias level - optimizes distortion, maximum output level and noise .
Playback level - the 1 kHz tone on a special calibration tape is played and the output aligned to the studio's electrical standard level.
High frequency playback EQ - the 10 kHz tone on the calibration tape is played and the HF EQ adjusted.
Record level - a 1 kHz tone at the studio's standard electrical level is recorded onto a blank tape and the record level adjusted for unity gain.
HF record EQ - adjusted for flat HF response.
LF record EQ - adjusted for flat LF response.
51. Explain the need for monitoring in sync.
Sync means that the new tracks you are recording match up with the tracks already on the tape. Since the playback head is a few inches away from the record head, you would hear a delay if you didn’t have sync output on the machine.
52. Why is the sync signal inferior to the playback signal?
It doesn’t sound as good coming from the record head as it would from the playback head. The record head is optimized for recording.
53. Why does this matter in track bouncing?
You need to make sure you are listening the playback head to get the best sound. Once you bounce, you can’t change the mix of the bounced tracks.
54. Is it possible to edit 2" analogue tape?
Yes, you can cut it and tape it back together. SCARY. No thank you.
55. Is it possible to synchronise two 24-track recorders?
Yes, both tapes would need to be striped with SMTPE. You have to determine which is the slave and which is the master.
56. 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?
A personal computer is not using all of its resources for the recording system. An integrated disk recording system is dedicated to recording, so it would be faster.
57. Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
We are moving toward more digital recording, in fact many studios in the US are digital only. But some artists still prefer analog, especially when they have been recording for a while (before digital was really popular) and those that have the money to afford it. There are also many engineers who prefer analog for its warmer sound. The most common analog recorders are made by Studer, Ampex and Otari. We still need to learn analog as a background for digital recording. Still, as digital recording gets better and better, analog may be extinct in our lifetime, or at least considered more “vintage” than it is now.
58. If a tape recorder has 24 inputs and 24 outputs, how many tracks will it have?
The number of tracks depends on the tape you are using. Usually a 24-track machine uses 2-inch tape with 24 tracks. But there is 2-inch 16 track tape also.
59. How many inputs and outputs would a disk recorder need if it was to be a replacement for a 24-track tape recorder?
That would depend on how many instruments you want to record at one time. If the disk recorder had only 8 inputs and outputs, you could still record 24 tracks, just have to do it 8 at a time.
60. 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 instruments at a time.
61. What information is stored in the session file?
Tracks, sound files needed, plug-ins, sample/bit rate.
62. Are session files usually transportable between different systems?
No , usually different software has different session files.
63. Comment briefly on the suitability of SCSI, ATA and Firewire disks for audio recording.
SCSI stands for Small Computer Systems Interface. It is a high speed parallel interface for hard disks, CDRoms Scanners, etc.
ATA drives are slower and may have buffer problems where they can bottle neck the transfer of data causing a loss of data.
Firewire (IEEE) is a fast connection, however it’s not very popular in PCs. Firewire is actually MACs trademarked name for IEEE connections.
64. What is 'fragmentation'?
When you save a file several times, all of the file information is not stored sequentially in the drive, the computer puts the new info in the next available open space. The more fragmented the drive, the slower the file will run.
65. Comment on archiving to CD-ROM
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It’s a viable solution but you would most likely need several discs. DVD would be better because you could fit more on each disc.
66. What are 'virtual tracks'?
Before the advent of affordable digital tape and budget hard disk recording systems, MIDI virtual tracks were a great way to make high-quality recordings. If you had MIDI tone generators, some signal processors, and a mixer, you could compose in a sequencer, send the data to the MIDI gear, and mix down in real time to DAT or analog tape. The name "virtual tracks" came about because the various MIDI sounds acted like tape tracks and were mixed down like tape tracks, but weren't tape tracks -- the audio was derived by playing back data recorded in a sequencer through a tone generator, in real time.
67. What is meant by 'edit density'? What are the implications of high edit density?
Edit density refers to processing operations in the background while the user continues to edit. Edit density is measured in ms. High edit density requires more RAM. The higher the edit density, the faster you can edit. Using more tracks reduces edit
68. Does the editing and trimming of regions delete audio data from the disk?
No, you can undo these changes and get the data back.
69. In editing, what is the difference between 'slip' and 'grid' modes?
In slip mode you can move the audio around freely, In grid mode you can only move the audio by grid sections. The user can determine size of the grid sections.
70. When might it not be possible to create a crossfade?
You cannot create a crossfade in a loop. The crossfade will take a small amount of audio information from the beginning and end of the selection, therefore, the selection cannot be from the very beginning or end of a sample (where there will be no information to draw from).
71. What is 'bouncing', in the context of mixing?
Sending several tracks to one empty track. This frees up the original tracks and you can record more instruments.
You have to be happy with the mix of the bounced tracks, you won’t be able to change it later.
72. What is meant by 'latency'? What is the difference between DSP processing and host-based processing?
Latency is the lag time between the input and output of audio recording software. DSP is Digital Signal Processing, where the software is doing the processing. In host-based processing, the computer’s CPU handles the processing.
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Fri May 02, 2003 4:53 pm |
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Aidan
Joined: 08 Jan 2003
Posts: 38
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1.Describe the following equipment used by a DJ: Cartridge & Stylus,Pickup Arm,Turntables,Mixer.
The cartridge and stylus read the music from the record grooves and convert it to a signal which is sent up the pickup arm to amplifier and on to speakers.The pick up arm also ensures cartridge is maintained at correct level and tracks correctly.The cartridge and stylus usually favoured by DJs are Staunton and Shure-hard wearing and able to cope with back cueing ie turning record backwards by hand.The turntable ensures the record revolves at correct speed-favorites among Djs are Technics SL1200 & SL1210 which have very powerful direct drive motors and ensure records can start at correct speeds instantaneously. A mixer is used to fade between records with some having rudimentary samples built in.
2.Why cannot the output of the cartridge be connected directly to a mixing console?
Because the signal of a cartridge is too low-typically between 0.5mv and 5mv and needs to be boosted to around 100mv to drive a line level input.In addition LPs are equalised using a RIAA system which needs to be reversed to give a line level input.
3.Why is it convenient to DI a synthesizer?
Because its signal is sufficient to drive line level inputs and it doesnt require amplification which may colour the sound.
4.Comment on the stereo output of many synthesizers.
5.Why might it be more desirable to amplify and mic up a synthesizer,as you would an electric guitar?
To get a more live sound,less sterile and to perhaps gain some distortion of the sound.
6.Comment on the use of loops in recording.
Its fair to say that the use of loops in recording has been a revelation and has enabled a lot of people with no formal training or playing skills to create music.basically loop slicing programs such as Propellerhaed Recycle,Sonic Foundry Acid and Ableton Live allow you to freely mix and match nearly any repeating rhythmic or melodic passage. These programs do away with time consuming editing processes when sampling and effectively sample for you.The Propellerhead Recycle program uses transient detection to determine where peaks in an audio file are located,it seeks out sudden volume changes that indicate attack and then places flags or markers to indicate where slices are to be made.These slices can be exported to a seperate file for playback and can be layered within an audio sequencer.Loops can be created from provided elements,sound libraries,new recordings or appropriated elements.Provided elements are usually used during remixing and are authorised by label or artist.Sound libraries include CDs and CD Roms with new original recordings being made to order.Appropriated elements are where samples are taken from recorded material with clearance being obtained if a commercial release is to be made.
7 Comment on tape loops.
8 Comment on looping using a sampler and sequencer.
9.Why is the sample looped using the sequencer in preference to looping it in the sampler?
Sampling a loop is the technique of sampling a musical phrase and retriggering it to create an illusion of a continuous musical part.You can make it continuous by looping the sample itself but used within a sequence the timing will drift unless your loop length is matched precisely to the tempo of your sequencer. A more satisfactory approach is to retrigger the sample from the sequencer-if your loop is say 4 bars long you then play a new note every 4 bars.
10.Comment on the significance of synchronising the sequencer to multitrack tape
Its essential that the multitrack has a dedicated sync in and out function or that it is possible to access the output from the sequencer directly without needing to add it to the stereo mix.A MIDI FSK(Frequency Shift Keying) syncbox is connected between the sequencer and the multitrack.The time code is recorded on one track of the multitrack,its then played back through the MIDI to tape sync unit with its MIDI out patched to the sequencer MIDI in with the sequencer set to external MIDI sync mode.As soon as you start the tape at the start of the song the sequencer will start in sync with it. |
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Fri May 02, 2003 9:10 pm |
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Aidan
Joined: 08 Jan 2003
Posts: 38
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12.What is timecode?
Timecode is a MIDI synchronisation code made up aof a series of pulses whuich perform same function as the sprockets holes in cine film-that is to give precise time information.
13.Comment on LTC,VITC & MTC.
LTC is Longitudinal Time Code-time code which is recorded onto a video or audio cue track.LTC encodes the biphase time code signal onto an analog audio or cue track as a modulated square wave signal.
MTC MIDI Time code-a system for easily & cost effectively translating SMPTE time code into an equivalent time code that conforms to the MIDI 1.0 spec.It also allows for time based code and commands to be distributed throughout the MIDI chain to devices or instruments capable of understanding and executing MTC commands.
VITC-Vertical Interval Time Code-used in video systems and is incorporated into the video signal during initial recording.It is part of video signal and is used at normal or lower speeds.
14.Comment on MIDI Clock.
Sequencers and drum machines have internal tempo clocks-an invisible timing grid on which all notes or beats are superimposed.It enables two or more MIDI pieces of equipment to be run in perfect synchronisation -with one acting as master and others as slaves eg allowing 2 drum machines to run in sync.
15.Why is it desirable to synchronise two MIDI units via MIIDI Clock?
It enables them to run in sync and ensures no timing errors.One can act as a master allowing you to change tempo on this one and automatically changing tempo on other slave units.
16.How does MTC correspond to MIDI clocks and Song Position Pointers?
17.Why is it desirable to synchronise a sequencer to multitrack tape?
To ensure the sequencer is synchronised in time with any recorded tracks on the multitrack.Depending on the multitrack it can be done via MTC or MIDI clock.
18.Comment on the two stages of building up a recording on multitrack tape with the aid of a sequecer.
You can record your parts into the sequencer and edit them to desired effect.You can then record them onto multitrack in combination with recorded sounds.
19.What is an audio sequencer?
A device for recording and replaying MIDI data, usually in multitrack format,allowing complex compositions to be built up a part at a time.
20.Is an audio sequencer suitable as a replacement for a multitrack tape recorder?
No.It should really be seen as an addition to a multitrack rather than a replacement. A sequencer only stores data not the sounds-its like an electronic score which can be played back on any MIDI equipped instrument.It allows you to layer sounds and create complete compositions which can be replayed on synth modules and then sent straight to multitrack to combine with traditionally recorded instruments.It cannot replace a multitrack as it only stores data not sounds.
21.Comment on the suitability of an audio sequencer for sample and loop editing?
22.Why is it not straightforward to synchronise an audio sequencer to a multitrack tape?
23.What parameters of effects can be controlled via MIDI?
Foot pedals,volume control,modulation,pitch bend.
24.Why would you want to control effects parameters by MIDI?
It would assist in changing parameters for all devices connected-it would mean changing reverb for one part,chorus another and so on.It enables you to change effects globally .
25.Does MTC come in all thre frame rates of SMPTE/EBU timecode?
Its sent in short bursts of 4 to each SMPTE frame and it takes 8 of these quarter frame messages to make up one completw set of location data.
26.Does MTC contain an address?
27.Does MTC contain a clock?
Yes
28.Is MTC useful for synchronising a MIDI sequencer?
Yes as most sequencers are able to lock to MTC.
29.Is MTC useful for synchronising digital data?
30.1Is MTC useful for synchronising analogue audio?
31.Comment on the difference between standalone hard disk recorders and computer based hard disk recorders.
Hard disk recorders are generally more robust and less prone to crashing than computers.They are purpose made for recording while PCs are built to perform many different tasks.To use effects with a hard disk recorder
you will need to use special units while with a PC you can use software plugins/effects which are often free and downloadable on the Net.
Hard disk recorders are simple to use and dont require extensive knowledge while PCs will require some training-however PCs will offer much greater visal feedback as against Hard Disk recorders which generally have less visual content.
32.Why is it a problem to use hard disks for longterm storage?
As its only a relatively new form of storage the jury is out on how long it will last.
33.Onto what media does backup/archival storage take place?
CDs,DVD,Tape,MiniDisc,Floppy Disks,Zip drives ,RAM.
34.What are the advantages of standalone hard disk recorders for editing?
You can edit time after time on hard disk recorder and always know the original is safe while with tape you only have one chance to get it right. |
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Sat May 03, 2003 4:50 pm |
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Aidan
Joined: 08 Jan 2003
Posts: 38
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36.Comment on the use of PRo Tools as an accessory to multitrack tape
You can record on Pro Tools and sync the playback to a tape machine.You can then add MIDI,Loops etc .You can also load tracks into Pro Tools and edit them again and again without touching original track.
37.List the common digital multitrack formats and describe their characteristics.
DAT-Digital Audio Tape- originally intended as a replacement for cassettes but never took hold in the consumer market.It uses a rotary head recorder to lay tracks diagonally across width of the tape-similiar to a VCR.
DASH-Digital Audio Stationary Head-uses normal hal inch tape which allows 24 Digital Audio tracks,2 analog cue tracks,a control track and a timecode track.It has a record and playback head.
ADAT-Alesis Digital Audio Tape-capable of 8 tracks with recordings made on video tapes.Tapes need to be formatted before use.
DTRS-Digital Tape Recording System-Tascam came up with this system which is much tthe same as ADAT but with a longer recording time.
Disk Recording-hard drive on a computer which can then be transferred to other mediums such as CD for playback.
38.What is formatting?
This is the procedure required to prepare a computer disk for use.It organises the disks surface into a series of electronic holes into which data can be stored.
39.What are the advantages and disadvantages of digital multitrack compared to analogue multitrack?
Advantages are no wow and flutter,little SNR,no degradation on copying,more features and ability to easily store data.
Disadvantages are that digital sounds are less warm sounding and when signal is overloaded the resultant distortion is very nasty.
40.Compare the maintenance and cleaning of an analogue recorder to that of a digital recorder.
Apart from using a specialised cleaning head tape there is nothing you can clean on a digital recorder.However on an analogue recorder you can adjust heads,clean heads and rollers,check alignment of heads as well as demagnetizing heads.
41.Who carries out routine maintenance?
The studio maintenance man/woman if its a large studio but more often than not the recording engineer.
42.Describe how the heads and guides of an analogue machine are cleaned.Mention the materials used.
You can clean the heads and metallic parts with cotton buds dipped in pure or isopropyl alcohol.
43.Describe how the pinch roller of an analogue machine is cleaned.Mention the materials used.
Opinions vary but a light use of isopropyl alcohol on cotton buds can be used.This method may over time result in hardening and cracking of the rubber which can be counteracted with the use of a small amount of tipex thinner fluid.However its probably best to use a combination of water with a very small amount of detergent to clean rollers.
44.What are the effects of neglected cleaning?
Build up of magnetism on metal parts which can erase tape subsequently played on the machine and build up of dust particles which can effect efficiency of motors and acn cause drop outs or fades on tapes.
45.Why must an analogue machine be periodically demagnetised?
To prevent the build up of magnetism which can erase parts of tape subsequently played back on the machine.
46.What happens if a machine is never demagnetised?
The metal parts will collect residual magnetism thay will partially erase any tapes played on the machine.
47.What might happen if the demagnetising is operated incorrectly?
Incorrect operation colud lead to build up of or creation of further levels of magnetism.
48.Why do analogue recorders need to be lined up?
Essentially to ensure machine is operating at its most efficient and also to ensure tapes recorded on one machine can be accurately played back on any another machine.
49.Do digital recorders ever need to be lined up?
No
50.Comment on the three elements of line up.
The three elements are Azimuth,Bias and Playback/Record levels.
Azimuth-this ensures that heads are vertical to avoid HF cancellation.
Bias level-optimises distortion,maximum output level and noise.
Playback/Record-levels of both HF and LF levels are adjusted to standard levels.
51.Explain the need for monitoring in sync.
A syn output is taken from the record head rather than playback head to avoid timing delays-monitoring in this way ensures the musician are in sync and timing is right.
52.Why is the sync signal inferior to the playback signal?
Because its coming from the record head rather than the playback head.
53.Why does this matter in track bouncing?
Beacause a syn output is taken from the record head rather than playback-you need to bounce from record head to ensure tracks are in sync.
54.Is it possible to edit 2" analogue tape?
Yes.You can splice together best sections of a tape.Its placed in a special metal block and cut with a razor blade and put back together with splicing tape.
55.Is it possible to synchronise two 24 track recorders.?
yes
56.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?
Because the less peripheral things on a PC the better -less chance of brweakdowns and more power and capacity for music creation.
57.Comment on the presentation of some disk recorders as replacements for tape multitrack recorders.
58.If a tape recorder has 24 inputs and 24 outputs,how many tracks will it have?
24
59.How many inputs and outputs would a disk recorder need if it was to be a replacemnent for a 24 track recorder?
24
60.If a disk recording system had two inputs,two outputs and was capable of twenty four tracks,what would be its main limitations?
Only two tracks could be recorded simultaneously.
61.What information is stored in the session file?
Project title-audio files used-Edits-Track assignments-Mix and Plug In data.
62.Are session files usually transportable between different systems?
No- if you record a session and edit it on Pro Tools with say 16 inputs/outputs using a particular combinationof plugin effects-it may not playback well on a ProTools set up with less inputs/outputs and with different plugins.In addition session files are highly incompatible between manufacturers.
63.Comment briefly on the suitability of SCSI,ATA and Firewire disks for audio recording.
ATA (aka IDE or EIDE)disks are cheap but are not the fastest .SCSI is a faster medium allowing disks to be located external to computer and daisy chained to enable several to be connected at same time.Firewire is actually an interface rather than a disk and is supposedly faster than ATA or SCSI.
64.What is fragmentation?
A fragmented drive contains pieces of files spread over different physical locations and makes the job of streaming data to and from that disk very difficult.A defrag program is used to clean up the disk and prepare it for recording or playing audio.
65..Comment on archiving to CD ROM.
66.What are virtual tracks?
Disk recorders can store additional virtual tracks which are in synchronisation with regular tracks but cannot be allocated to an output-they can be easily interchanged.
67.What is meant by Edit Density? What are the implications of high edit density?
When an audio file is recorded it is recorded in long continuous sections on the disk.When material is edited the regions are broken up and not continuous causing the heads to move more often to retrieve data.Edit density refers to number of regions ,their length and proximity to each other and how far they are physically seperated on disk.Greater the density-fewer tracks will play.
68.Does the editing and trimming of regions delete audio data from the disk?
No- the edited or trimmed data is merely seperated and silenced.
69.In editing what is the difference between slip and grid modes?
Slip mode means that as there is no fixed time relationship between tracks a track may slip or move with respect to others.Grid mode is where tracks are fixed to grid positions.
70.When might it not be possible to create a crossfade?
If there is no material beyond your designated region/track boundaries or insufficient for the desired duration of the crossfade,then a crossfade cannot be created.
71.What is bouncing,in the context of mixing?
It means bouncing a mix to a stereo file on the disk.
72.What is meant by latency?What is the difference between DSP processing and host-based processing?
Computers use buffers which are short time periods during which a processor performs its functions-if the buffer takes more than 10 milliseconds it can be clearly audible on overdubbing and is called latency.Host based processing is where the computer itself performs calculations and DSP or digital signal processing is where special chips or cards are used to process calculations e.g. Digidesign ProTools mixing and plugin effects. |
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Mon May 05, 2003 2:11 pm |
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AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Bang On |
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Great stuff Aidan, you did really good there!
Chrish |
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Mon May 05, 2003 2:56 pm |
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All times are GMT. The time now is Fri May 16, 2008 3:54 pm
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