AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Week 10 - Synchronisation |
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Modular digital multitrack recorders, midi to multitrack, multitrack to video, multitrack to multitrack.
Here we go folks. Good luck!
1. Explain why it is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously.
2. Explain why some multitrack hard disk recording systems can play back much slower than normal speed, but only a little faster.
3. State TWO major advantages of hard disk recording systems over digital tape recorders.
4. Describe THREE major operational advantages of having two modular digital multitrack recorders such as the ADAT or DTRS formats over a format which records sixteen tracks on the same tape on a single machine.
5. Explain why the punch in process on a hard disk recorder is more flexible than that on an analogue or digital tape recorder.
6. With reference to an analogue multi-track recorder briefly explain
a) the term `sync' output
b) why the `sync' output is required when overdubbing.
7. It is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously. Why is this?
8. Some hard disk recording systems have mixing facilities so that several tracks can be mixed into a stereo output. If no other outputs are available why must the system incorporate reverb internally?
9. What are the two major advantages of hard disk recording systems over digital tape recorders?
10. What piece of equipment is necessary to use a sequencer with a multitrack tape recorder?
b) Why is it preferable to use MTC rather than MIDI clocks and Song Position Pointers when synchronising a sequencer to a tape recorder?
c) If MIDI Machine Control (MMC) is not used, describe briefly the two distinct stages of operation when recording a piece of sequenced music to multitrack tape.
d) What is the advantage of MMC?
e) In a system using MMC, while playback or recording progresses the multitrack and sequencer will be running in sync. At this moment which is master and which is slave?
11. You have been given an unlabelled tape to play which starts with a warbling tone. What noise reduction system might have been used?
b) You have been given an unlabelled tape to play which starts with noise. What noise reduction system might have been used?
c) Name three domestic noise reduction systems invented by the Dolby company.
d) Give the name of another fairly common analogue noise reduction system.
e) Where would you find the ATRAC digital noise reduction system?
12. When recording onto analogue or digital multitrack tape, in a situation where synchronisation is going to be used, what procedure must be carried out before any recording can begin?
b) Your studio manager has given you a multitrack tape containing music and timecode to copy. What must you do to ensure that the timecode is copied correctly?
c) A multitrack tape of a band with no sequenced instruments was striped with timecode at the start of the session and has subsequently been edited? Would it be good practice to use the existing timecode as a synchronisation reference for the console automation system during the mix?
d) Referring to c) above, why would it not be a problem to re-stripe the tape with timecode and erase the original timecode, even if the generator does not have a jam sync function?
e) You have striped timecode on track 24 of an analogue tape and recorded a bass guitar on track 23. When you try and synchronise a MIDI sequencer using a cheap timecode to MTC convertor, the sequencer often stops or loses sync. Why?
13. When working with MIDI and multitrack tape, does the multitrack recorder synchronise to the sequencer or does the sequencer synchronise to the multitrack tape?
b) When working with an ADAT recorder, why wouldn’t you necessarily have to stripe the tape with timecode to synchronise a sequencer?
c) Imagine that several tracks of a MIDI sequence have been transferred to multitrack tape. The producer decides that he wants to varispeed the tape a little faster. Should this be done before or after the remaining sequencer tracks have been transferred to tape? Explain your answer.
14. Noise reduction systems such as dbx and Dolby cause the noise level in a recording to vary. Explain why this is so.
15. You have been asked to remix a song (in the sense of creating a completely new version) originally made on multitrack tape in the early 1970s.
a) What would be the main problem in synchronising a sequencer to the original tape?
b) If you decided only to use the vocal track from the original recording, how would you make the lines fit in time with your new MIDI sequencer arrangement?
c) Suppose you want the song to be around 15% faster in tempo. What should you do to speed up the vocals?
d) The record company decides that it wants to keep a lot of the original instrumentation, but also likes your strict tempo MIDI sequence. What type of equipment should you use to put everything together?
16. You are working with a multitrack recorder that will slave to SMPTE/EBU timecode from (for instance) a video machine, but has no other means by which it may be externally controlled. Imagine you stop the master machine, rewind the tape to the beginning and start playing. What will the multitrack do? |
Sun Jan 12, 2003 9:37 pm |
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resol69
Joined: 31 Dec 2002
Posts: 69
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| questions on the questions |
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Hi Chrish,
#1 and #7 are the same, yes?
Also, I found this sample test online. http://www.cwc.ac.uk/sound/past_papers/1820Pt3RT99.htm
for question #1, why is it digital only? you could record classical music in analogue ???
Thanks,
Nancy |
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Tue May 06, 2003 7:54 pm |
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AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Justify |
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Nancy, well spotted, (1) and (7) are indeed the question phrased slightly differently.
Regarding CWC past paper and model answer (1), this indicates why you must answer with authority.
Of course classical music can be recorded in the analogue domain. What the author is after is the understanding of the wider bandwidths involved with digital, (dynamic range and frequency) therefore, more suitable for the wider dynamic range of classical music. Whereas most modern POP has a much smaller dynamic range.
With that in mind I would never EVER give one word answers, always justify your responses.
Does that help?
Chrish |
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Tue May 06, 2003 8:11 pm |
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resol69
Joined: 31 Dec 2002
Posts: 69
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yes, I thought all those answers looked too skimpy!
Thanks,
Nancy |
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Tue May 06, 2003 8:16 pm |
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resol69
Joined: 31 Dec 2002
Posts: 69
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| Nancy |
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Didn't find as much detail as I would have liked on these. Here's what I have so far.
Found these sample tests online check them out. The answers are too short, but lead you in the right direction.
http://www.cwc.ac.uk/sound/past_papers/1820Pt3RT99.htm
http://www.cwc.ac.uk/sound/past_papers/1820Pt3MT99.htm
Other interesting links:
http://www.alexandermagazine.com/recordingeq/passSI/passv1/less56tx.htm
http://www.alexandermagazine.com/recordingeq/passSI/passv1/less55tx.htm#Virtual%20Tracking
http://www.alexandermagazine.com/recordingeq/passSI/passv1/less55tx.htm
http://www.sospubs.co.uk/sos/aug98/articles/datacompression.html
http://www.dolby.com/cassette/bcsnr/
http://www.audio-restoration.com/baking.htm
1. Explain why it is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously.
You may want to record several takes of a certain instrument. You would need them all to be in sync but you would only play them one at time.
2. Explain why some multitrack hard disk recording systems can play back much slower than normal speed, but only a little faster.
Because data has to be retrieved from the disk at a faster rate than normal. The rate of data transfer is one of the limiting factors on how many tracks can be played back simultaneously.
3. State TWO major advantages of hard disk recording systems over digital tape recorders.
It’s much easier to edit on hard disk recording system. You can easily cut and past and undo it if you don’t like the results. You can also access any part of the material very easily, just point and click to where you want to go. Digital Tape is linear, you have to fast forward and rewind to where you want to go, so it takes longer.
4. Describe THREE major operational advantages of having two modular digital multitrack recorders such as the ADAT or DTRS formats over a format which records sixteen tracks on the same tape on a single machine.
With two machines tapes can be copied.
Tapes can be edited by copying from one machine to the other using an offset.
More than two tapes can be used to record alternative takes of vocals, solos etc.
5. Explain why the punch in process on a hard disk recorder is more flexible than that on an analogue or digital tape recorder.
Punching in or out on hard disk recorders is non-destructive. If you punch in at the wrong spot on a hard disk recorder, you can get the original take back and try again. Punching in on analogue or digital tape is destructive. If you punch in or our at the wrong spot, you may have to re-record some music. You can’t undo it.
6. With reference to an analogue multi-track recorder briefly explain
a) the term `sync' output
Sync means that the new tracks you are recording match up with the tracks already on the tape.
b) why the `sync' output is required when overdubbing.
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.
7. It is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously. Why is this?
You may want to record several takes of a certain instrument. You would need them all to be in sync but you would only play them one at time.
8. Some hard disk recording systems have mixing facilities so that several tracks can be mixed into a stereo output. If no other outputs are available why must the system incorporate reverb internally?
You need to route the signal to the external reverb unit. Without an aux send, there is no way to get it from the hard disk to the reverb.
9. What are the two major advantages of hard disk recording systems over digital tape recorders?
It’s much easier to edit on hard disk recording system. You can easily cut and past and undo it if you don’t like the results. You can also access any part of the material very easily, just point and click to where you want to go. Digital Tape is linear, you have to fast forward and rewind to where you want to go, so it takes longer.
10. What piece of equipment is necessary to use a sequencer with a multitrack tape recorder?
A SMPTE Time Code Generator is needed to record the Time Code onto a track of the multitrack tape machine. The code encodes hours, minutes, seconds and partial seconds (called "frames") onto the tape. A SMPTE reader can then display the tape positions in how many hours, minutes, seconds and frames you are "into" the reel. Some sequencers can be set to respond to SMPTE Time code and will have a" SMPTE T/C In" jack on the machine.
The sequencer must be set to respond to SMPTE T/C and two additional settings must be made to have the sequencer sync to the tape:
Offset Time: This is the hours, minutes, seconds and frames of where you want the tune to be recorded on the tape. When you play the tape, the sequencer will begin playing when the SMPTE Time Code reaches the offset time.
Tempo: This is how many beats per minute you want the tune to play at.
b) Why is it preferable to use MTC rather than MIDI clocks and Song Position Pointers when synchronising a sequencer to a tape recorder?
Midi Time Code(MTC) was developed to give midi devices an absolute reference point, much finer than bars or beats (which is what MIDI clock is) Tine contro (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.
c) If MIDI Machine Control (MMC) is not used, describe briefly the two distinct stages of operation when recording a piece of sequenced music to multitrack tape.
You have to strip the tape with SMPTE first and them dump the MIDI info on to the multitrack tape.
d) What is the advantage of MMC
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MIDI Machine Control (MMC) is a protocol specifically designed to remotely control hard disk recording systems, and other machines used for record or playback, over a MIDI cable.
(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.
e) In a system using MMC, while playback or recording progresses the multitrack and sequencer will be running in sync. At this moment which is master and which is slave?
I would guess the multitrack.
11. You have been given an unlabelled tape to play which starts with a warbling tone. What noise reduction system might have been used?
Still looking for info on this.
b) You have been given an unlabelled tape to play which starts with noise. What noise reduction system might have been used?
None?
c) Name three domestic noise reduction systems invented by the Dolby company.
Dolby B-type Noise Reduction
Dolby B-type noise reduction is the original Dolby system designed for consumer tape recorders. It is included in all but the least expensive cassette machines today, and is used in the preparation of the vast majority of prerecorded cassettes. It is also incorporated in many stereo VHS videocassette recorded to improve their linear audio tracks and, in a modified form, in Dolby Surround decoders. Dolby B-type provides 10 dB of noise reduction at the higher frequencies where tape hiss predominates.
Dolby C-type Noise Reduction
Dolby C-type noise reduction was developed to improve the cassette medium still further by providing twice the tape hiss reduction (20 dB) of Dolby B-type. It is offered along with Dolby B-type in a variety of mid-range and premium cassette decks and players. Dolby C-type is also used in many professional videocassette recorders.
Dolby S-type Noise Reduction
Intoduced in 1990, Dolby S-type is based upon the principles of the professional Dolby SR (Spectral Recording) process. It not only provides still more tape hiss reduction (24 dB), but also reduces low-frequency noise by 10 dB. It t permits recording high-level signals at the frequency extremes more accurately and cleanly.
d) Give the name of another fairly common analogue noise reduction system.
Dbx.: dbx noise reduction is a COMPANDER system; it compresses the audio signal at the encoding input (before recording onto tape) and expands the signal from tape playback out to the decoding output.
e) Where would you find the ATRAC digital noise reduction system?
Adaptive TRansform Acoustic Coding is the system employed by Sony on their Minidisc as well as in the SDDS cinema surround sound format. It offers a 5:1 data reduction ratio in the case of Minidisc and employs the equivalent of 52 filter bands for spectral analysis and re-quantisation.
12. When recording onto analogue or digital multitrack tape, in a situation where synchronisation is going to be used,what procedure must be carried out before any recording can begin?
You have to stripe the tape with SMTPE time code so it can be synchronized.
b) Your studio manager has given you a multitrack tape containing music and timecode to copy. What must you do to ensure that the timecode is copied correctly?
Make sure you have the master and not a copy: the timecode becomes unreliable after two generations. This means that you can copy the master to one tape, and copy that tape to another, but after that, you will have to reuse the master or regenerate the timecode signal because the signal may drop out and not be able to be read by the slave. Many generator boxes can take the incoming signal and regenerate new timecode in sync with the incoming signal. Regenerated time code is often called "Jam Sync."
Also be careful when setting the recording level of the timecode may be too high or too low. Set it to around -7dB to -5dB, or to the level the sequencer manufacturer suggests. When it’s too high, it can easily bleed on to an neighboring track. However, the signal should be hot enough that it can be read clearly by the receiving machine. Timecode should not be recorded with dbx noise reduction or with equalization. And make sure the tape heads are clean.
c) A multitrack tape of a band with no sequenced instruments was striped with timecode at the start of the session and has subsequently been edited? Would it be good practice to use the existing timecode as a synchronisation reference for the console automation system during the mix?
No, once a tape is striped with timecode, it cannot be updated. You need to re-stripe it.
d) Referring to c) above, why would it not be a problem to re-stripe the tape with timecode and erase the original timecode, even if the generator does not have a jam sync function?
Jam Sync re-generates the original timecode. You don’t need the original time code, since the tape has been edited, you need new time code.
e) You have striped timecode on track 24 of an analogue tape and recorded a bass guitar on track 23. When you try and synchronise a MIDI sequencer using a cheap timecode to MTC convertor, the sequencer often stops or loses sync. Why?
Bass insturments have high levels. The bass can bleed through to track 24 and mess up the timecode track.
13. When working with MIDI and multitrack tape, does the multitrack recorder synchronise to the sequencer or does the sequencer synchronise to the multitrack tape?
The sequencer synchronizes to the multitrack.
b) When working with an ADAT recorder, why wouldn’t you necessarily have to stripe the tape with timecode to synchronise a sequencer?
ADAT is self clocking, it has timecode on it already.
c) Imagine that several tracks of a MIDI sequence have been transferred to multitrack tape. The producer decides that he wants to varispeed the tape a little faster. Should this be done before or after the remaining sequencer tracks have been transferred to tape? Explain your answer.
You should varispeed the tape first because it will be slightly sharper when you speed up the tape. The new material can them be recorded to match the new sound.
14. Noise reduction systems such as dbx and Dolby cause the noise level in a recording to vary. Explain why this is so.
Noise reduction has two phases. One is the encoding of the noise reduction on the tape. Then the noise reduction has to be decoded at the time of playback. Since different machines will be doing the decoding, the level can vary.
15. You have been asked to remix a song (in the sense of creating a completely new version) originally made on multitrack tape in the early 1970s.
a) What would be the main problem in synchronising a sequencer to the original tape?
The tape may not play. In the 1970's tape manufacturers made an ill-advised decision to change the formulation of the "binder" used to glue the magnetic tape particles to the plastic base material. Unknowingly, the new formulation attracted moisture, and eventually enough accumulated to make the tape go "sticky". The surface of the tape has become gummy and it sticks to the heads and fixed guides of the tape transport, squealing, jerking, and, in extreme cases, slowing down or stopping the tape transport. This problem has cropped up on all brands of tape, but is nearly always fixable, at least temporarily.
b) If you decided only to use the vocal track from the original recording, how would you make the lines fit in time with your new MIDI sequencer arrangement?
You can varispeed the tape our dump into a digital audio editor.
c) Suppose you want the song to be around 15% faster in tempo. What should you do to speed up the vocals?
Not sure. Does this have something to do with MIDI tempo maps?
d) The record company decides that it wants to keep a lot of the original instrumentation, but also likes your strict tempo MIDI sequence. What type of equipment should you use to put everything together
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You would use a multitrack to get the original instrumentation from the tape. Dump that into a digital audio editor/recorder. Hook up the sequencer to the recorder and record that into the same file.
16. You are working with a multitrack recorder that will slave to SMPTE/EBU timecode from (for instance) a video machine, but has no other means by which it may be externally controlled. Imagine you stop the master machine, rewind the tape to the beginning and start playing. What will the multitrack do?
Since it cannot be externally controlled, the multitrack would keep playing. You would have go to the machine, rewind it and hit play. |
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Thu May 08, 2003 9:39 pm |
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Dani
Joined: 28 Jan 2003
Posts: 35
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Modular digital multitrack recorders, midi to multitrack, multitrack to video, multitrack to multitrack.
Here we go folks. Good luck!
1. Explain why it is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously.
Being able to store more tracks than you can play back is usefull for recording multiple takes of a track so you can audition the different takes against each other without losing what was recorded origionaly.
2. Explain why some multitrack hard disk recording systems can play back much slower than normal speed, but only a little faster.
It is easier for the hardware to slow down the data rate from the hard drive than it is to speed up access. The is a finite amount of data that can be read from a hard drive, increasing the speed will reduce the number of tracks that can play at once.
3. State TWO major advantages of hard disk recording systems over digital tape recorders.
Two major advantages would be non-destructive recording (the ability to use "undo"). The ease of editing, with the facilty to move audio data around the timeline. Another advantage would be the use of Software Effects Plugins, which are often less expansive than their hardware counterparts.
4. Describe THREE major operational advantages of having two modular digital multitrack recorders such as the ADAT or DTRS formats over a format which records sixteen tracks on the same tape on a single machine.
Using two 8-tracks synced together means that you have the ability to use one cassette for backing tracks and maybe several cassettes for overdubs, compiling the best overdubs later onto one cassette for mixdown. If you have a catastrophic failure of a tape, you only lose half of your work and, to prevent that being a problem, you can back up your tapes by copying the entire eight track session onto another tape.
5. Explain why the punch in process on a hard disk recorder is more flexible than that on an analogue or digital tape recorder.
Punch-ins can be set more acurately by veiwng the existing wave form, it is entirely possible to punch in a single snare if need be. Almost like recording to a sampler. Secondly, the recdording process is non-destructive, giving you the freedom to improve a take, without the risk of losing an already good take.
6. With reference to an analogue multi-track recorder briefly explain
a) the term `sync' output
Sync output refers to the signal that comes from the record head of the multitrack tape machine.
b) why the `sync' output is required when overdubbing.
Sync output is used when recording overdubs because the play heads are in fact away from the record heads, if the performer was listening to the play heads their overdub would be out of sync when the track was played back and mixed from the play heads.
7. It is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously. Why is this?
To give the producer/enginner more flexibility when recording and editing different takes, like comping.
8. Some hard disk recording systems have mixing facilities so that several tracks can be mixed into a stereo output. If no other outputs are available why must the system incorporate reverb internally?
It has to incorporate reverb internally because there is no way for the signal to leave the hard disk recorder, pass through an external reverb unit and then come back into the hardware recorder without affecting the entire mix. Using internal reverb means each individual track can have reverb added only where nescesary.
9. What are the two major advantages of hard disk recording systems over digital tape recorders?
Non-destructive recording and ease of editing.
10. What piece of equipment is necessary to use a sequencer with a multitrack tape recorder?
A tape sync machine is required if you wish to syncronize a sequencer to a tape machine. SMTPE is the international standard for these types of machines, though there are other methods available.
b) Why is it preferable to use MTC rather than MIDI clocks and Song Position Pointers when synchronising a sequencer to a tape recorder?
Midi Time Code runs at a higher beat resolution and therefore keeps the sync "tighter".
c) If MIDI Machine Control (MMC) is not used, describe briefly the two distinct stages of operation when recording a piece of sequenced music to multitrack tape.
The first part of the process of recording a sequencer to a multitrack is to "stripe" the tape, this in effect lays down a data track over the entire length of the song which can be read either by a seperate machine or in some cases the sequencer itself. This allows the sequencer to know when the tape starts and stops. The second stage involves recording the audio from the MIDI devices being played by the sequencer. This can be done with everytrack being recorded on to two stereo tracks, or it can be recorded with a different instrument on different tracks.
d) What is the advantage of MMC?
MMC or MIDI Machine Control is used to sync different peices of hardware using the MIDI protocol. Sequencers and hardware recorders benefit from this by being able to sync together and depending on the circumstances can be set to master or slave.
e) In a system using MMC, while playback or recording progresses the multitrack and sequencer will be running in sync. At this moment which is master and which is slave?
In most cases you would have the multitrack as the master and the sequencer as slave, although there maybe times when you want it the other way round, for instance if you decided you needed to add another MIDI track to your sequence.
11. You have been given an unlabelled tape to play which starts with a warbling tone. What noise reduction system might have been used?
Possibly DBX?
b) You have been given an unlabelled tape to play which starts with noise. What noise reduction system might have been used?
Dobly
c) Name three domestic noise reduction systems invented by the Dolby company.
Dolby B - Dolby first commercial noise reduction system. During playback through a Dolby B-type decoder, there is effective noise reduction and no tape over-loading. Dolby B-type Noise Reduction does this by using a SINGLE, SLIDING COMPRESSION-EXPANSION BAND of frequencies. A sliding band is basically a filter that can shift its frequency breakpoint up and down. In B-type noise reduction, the frequency where the noise reduction action just begins can change from about 300 Hz all the way out to 20,000 Hz.
Dolby C - Introduced to the public in 1980, Dolby C-type provides 20 dB of noise reduction above about 1,000 Hz, fully doubling the amount given by B-type. Additional features were incorporated to deal specifically with the difficulties of recording on slow-speed consumer tape formats.
Dolby S - Like Dolby C-type, Dolby S-type uses TWO HIGH FREQUENCY SLIDING COMPRESSION-EXPANSION BANDS. But, in addition, EACH SLIDING COMPRESSION-EXPANSION BAND IS COUPLED WITH A SEPARATE HIGH FREQUENCY FIXED BAND PROCESSOR. By using these coupled processors, called Action Substitution, Dolby S-type noise reduction is able to provide 24 dB of HIGH FREQUENCY noise reduction.
d) Give the name of another fairly common analogue noise reduction system.
Another common form of noise reduction is dbx.
e) Where would you find the ATRAC digital noise reduction system?
On a mini-disk recorder.
12. When recording onto analogue or digital multitrack tape, in a situation where synchronisation is going to be used, what procedure must be carried out before any recording can begin?
A track most be chosen for the sync stripe, the the tape is striped with timecode.
b) Your studio manager has given you a multitrack tape containing music and timecode to copy. What must you do to ensure that the timecode is copied correctly?
Make sure the levels are correct for the timecode, watch out for bleed and/or drop outs.
c) A multitrack tape of a band with no sequenced instruments was striped with timecode at the start of the session and has subsequently been edited? Would it be good practice to use the existing timecode as a synchronisation reference for the console automation system during the mix?
If the tape has been cut then the timecode will be useless and cannot be used on the other hand, if the tape is unedited and the band have been playing to a click track and is infact in time, then the timecode can be used to sync an automation mix.
d) Referring to c) above, why would it not be a problem to re-stripe the tape with timecode and erase the original timecode, even if the generator does not have a jam sync function?
You can freely re-stripe the tape as there are no MIDI instruments to sync to, therefore the stipe does not have to be synced to anything external. It can however still syncronize the audio mix down. (which will be recorded after the stripe).
e) You have striped timecode on track 24 of an analogue tape and recorded a bass guitar on track 23. When you try and synchronise a MIDI sequencer using a cheap timecode to MTC convertor, the sequencer often stops or loses sync. Why?
You may be getting crosstalk or bleed from the bass guitar signal which confuses the converter.
13. When working with MIDI and multitrack tape, does the multitrack recorder synchronise to the sequencer or does the sequencer synchronise to the multitrack tape?
The sequencer syncronizes to the multitrack. It plays catch up.
b) When working with an ADAT recorder, why wouldn’t you necessarily have to stripe the tape with timecode to synchronise a sequencer?
An ADAT recorder has it's own sync which doesn't rely on external units such as SMTPE.
c) Imagine that several tracks of a MIDI sequence have been transferred to multitrack tape. The producer decides that he wants to varispeed the tape a little faster. Should this be done before or after the remaining sequencer tracks have been transferred to tape? Explain your answer.
This should be done before varispeed has been used. The shift in speed will also result in an upwards shift in pitch . The origional audio data will then therefore be at a slightly different pitch to the MIDI coming from the MIDI equipment, although still in sync. If there was no choice but to record after using varispeed then the subtle use of pitch bend or the synths intenal fine tuning could be used to match pitches.
14. Noise reduction systems such as dbx and Dolby cause the noise level in a recording to vary. Explain why this is so.
Because most noise recuction systems use "compansion" (compression/expansion).
15. You have been asked to remix a song (in the sense of creating a completely new version) originally made on multitrack tape in the early 1970s.
a) What would be the main problem in synchronising a sequencer to the original tape?
Problems could arise from matching the tempo exactly and syncing any subtle tempo changes.
b) If you decided only to use the vocal track from the original recording, how would you make the lines fit in time with your new MIDI sequencer arrangement?
By recording them into a sampler and playing them back a phrase at a time, or recording them into a DAW and timestretching the vocals to fit the MIDI.
c) Suppose you want the song to be around 15% faster in tempo. What should you do to speed up the vocals?
Timestretching.
d) The record company decides that it wants to keep a lot of the original instrumentation, but also likes your strict tempo MIDI sequence. What type of equipment should you use to put everything together?
Record everything thing into a computer based recording system, sync the tempo and import your MIDI data.
16. You are working with a multitrack recorder that will slave to SMPTE/EBU timecode from (for instance) a video machine, but has no other means by which it may be externally controlled. Imagine you stop the master machine, rewind the tape to the beginning and start playing. What will the multitrack do?
The multitrack should also rewind and play, provding the machine has given over transport controls to the SMTPE/EBU device. |
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Sat May 10, 2003 12:24 pm |
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Aidan
Joined: 08 Jan 2003
Posts: 38
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1. Explain why it is common for a multitrack hard disk recording system to be able to store more tracks in synchronisation than it can play simultaneously.
They enable you to record a lot of alternate takes or runthroughs and store these.They can then be reviewed with the best being used-basically a note pad.
2.Explain why some multitrack hard disk recording systemsa can play back much slower than normal speed,but only a little faster.
Becuse data has to be retrieved from the disk at a faster rate than normal.
3.State Two major advantages of hard disk recording systems over digital tape recorders.
More flexible editing and better speed of access to any part of the material
4.Describe three major advantages of having two modular digital multitrack recorders such as the ADAT or DTRS formatsover a format which records sixteen tracks on the same tape on a single machine.
The advantages would be that with two machines tapes could be copied from one machine to the other.,tapes can be edited by copying from one machine to the other using an offset and more than two tapes can be used to record alternative takes of vocals,solos etc. |
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Sat May 10, 2003 8:52 pm |
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Aidan
Joined: 08 Jan 2003
Posts: 38
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5.Explain why thje punch in process on a hard disk recorder is more flexible than that on an analogue or digital tape recorder.
Because on a hard disk recorder you can punch in as many times as you like without comitting yourself.You can try again and again to get right point to punch in while on an analogue or digital recorder you may have to rerecord again if punch in is not accurate.
6.With reference to an analogue multi track recorder briefly explain:
a) the term sync output
b) why the sync output is required when overdubbing
Sync output refers to the output taken from the record head of a multitrack recorder.There are two heads on a multitrack recorder:Playback and Record,which are spaced apart and give rise to a slight delay .When overdubbing this slight delay may be noticeable if the playback head was used to monitor signal so a sync output is taken from the record head.
7.Same as Question 1
8.Some hard disk recording systems have mixing facilities so that several tracks can be mixed into a stereo output.If no other outputs are available why must the system incorporate reverb internally?
If there are no auxiliary sends then there is no means of sending signal to an outboard effects unit therefore an internal effects must be used.
9.What are the two main advantages of hard disk recording systems over digital tape recorders?
Editing and accessibility.Its easier to edit by cutting and pasting sections and its easier to access sections of data.
What piece of equipment is necessary to use a sequencer with a ultitrack recorder?
A MIDI FSK(Frequency Shift Keying) Sync box.
b)Why is it preferable to use MTC rather than MIDI clocks and Song Position Pointers when synchronising a sequencer to a tape recorder?
Because its a more accurate system based on absolute time rather than based on tempo clock.
c.If MIDI Machine control(MMC) is not used,describe briefly the two distinct stages of operation when recording a piece of sequenced music to multitrack tape.
The sequence to be recorded is played back through a MIDI sync box while the time code is recorded on one track of the recorder.To playback you platy the time code track back through the sync box-patching its MIDI out to the sequencers MIDI in with the sequencer set to external MIDI sync mode.As soon as you run the tape from the start of the song the sequencer will start in sync with it.
d) What is the advantage of MMC?
It enables you to remotely control hard disk recording systems and other machines used for record and playback with a standard MIDI cable.
e.In a system using MMC,while playback or recording progresses the multitrack and sequencer will be running in sync.At this moment which is the master and which is the slave?
Multitrack
11.You have been given an unlabelled tape to play which starts with a warbling tone.What noise reduction might have been used?
b) You have been given an unlabelled tape to play which starts with noise.What noise reduction might have been used?
c.)Name three domestic noise reduction systems invented by the Dolby company.
DolbyB.Dolby Cand Dolby S. Dolby B was introduced to consumer market in 1970 with Dolby C following in eighties.
d) Give the name of another fairly common analogue noise reduction system.
dbx.
e.)Where would you find the ATRAC digital noise reduction system?
On the Sony Minidisc recorders and on SDDS cinema surround sound.It stands for Adaptive Transform Acoustic Coding and is a compression system using amongst others,threshold of hearing and masking effect principles to compress audio data to approximately one fifth of its original size,with no loss in sound quality.
12.When recording oto analogue or digital multitrack tape,in a situation where synchronisation is going to be used,what procedure must be carried out before any recording can begin?
Striping of the tape using SMPTE or MTC codes. |
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Sun May 11, 2003 3:44 pm |
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Aidan
Joined: 08 Jan 2003
Posts: 38
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12.b.) Your studio manager has given you a multitrack tape containing music and timecode to copy.What must you do to ensure the timecode is copied correctly?
Ensure you do not record the timecode at too high a level onto new tape as timecode can leak to adjacent tracks.Alternatively ensure nothing is recorded on adjacent tracks to timecode although may inhibit use of tracks.
c) A multitrack tape of a band with no sequenced instruments was striped with timecode at the start of the session and has subsequently been edited?Would it be good practice to use the existing timecode as a synchronisation reference for the console automation during the mix?
No -its best to start with a new timecode to ensure reliability.
d.)Referring to c)above,why would it not be a problem to restripe the tape with timecode and erase the original timecode,even if the generator does not have jam sync function?
The jam sync function is to regenerate timecode while in this case the original timecode is intact.You only need to restripe timecode again.
e)You have striped timecode on track 24 of an analogue tape and recorded a bass guitar on track 23.When you try and synchronise a MIDI sequencer using a cheap timecode to MTC convertor,the sequencer often stops or loses sync.Why?
The bass could be leaking onto the timecode.A bass will have very low frequencies which can often leak onto adjacent tracks.
13.When working with MIDI and multitrack tape,does the multitrack recorder synchronise to the sequencer or does the sequencer synchronise to the multitrack tape?
The sequencer synchronises with the multitrack. A synchronisation tone is recorded onto multitrack and the sequencer chases the tape.
b.) When working on an ADAT recorder,why wouldnt you necessarily have to stripe the tape with timecode to synchronise a sequencer?
ADAT has its own timecode already on tape.
c.)Imagine that several tracks of a MIDI sequence have been transferred to multitrack tape.The producer decides that he wants to varispeed the tape a little faster.Should this be done before or after the remaining sequencer tracksa have been transferred to tape?Explain your answer.
Probably after the remaining sequncer tracks are transferred onto tape as you can then varispeed the whole tape with all parts and ensuring all tracks are speeded up at same rate.
14.Noise reduction systems such as dbx and Dolby cause the noise level in a recording to vary.Explain why this is so.
Noise reduction systems such as dbx and Dolby use data compression to compress signal on recording and expand it on playback-different machines used on record or playback can give varying degrees of noise levels.
15. You have been asked to remix a song originally made on multitrack tape in the early 1970S.
a.) What would be the main problem in synchronising a sequencer to the original tape?
The tape probably wasnt recorded to a click track or a strict tempo map and timing may vary.These irregularities in timing will show up whem synchronising a sequencer to tape.
b.)If you decided only to use the vocal track from the original recording,how would you make the lines fit in time with your new MIDI sequencer arrangement?
Use a Recycle application which allows you to splice audio into manageable parts and allows you to make tempo changes to parts without changes in pitch.
c)Suppose you want the song to be aroung 15% faster in tempo.What should you do to speed up the vocals?
Sample them into Recycle application as in b.) above
d.)The record company decides that it wants to keep thea lot of the original instrumentation,but also likes your strict tempo MIDI sequence.What type of equipment should you use to put everything together?
Use a multitrack to record parts you want to keep onto and the add your MIDI sequence.
16.You are working with a multitrack recorder that will slave to SMPTE/EBU timecode from a video machine,but has no other meansa by which it may be externally controlled.Imagine if you stop the master machine,rewind the tapoe to the beginning and start playing.What will the multitrack do?
The multitrack would keep going. |
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Mon May 12, 2003 6:37 pm |
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