AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
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| Week 4 - Questions |
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1. What is the function of mixing desk automation?
2. Why might the faders have to be moved during the mix?
3. What aspects of mixing would normally be automated on an analogue console?
4. Comment on VCA vs. Moving Fader automation.
5. Describe write/update/read.
6. How does an automated mix session start?
7. How would a section of automation data be re-recorded?
8. How are automation 'punch-ins' blended smoothly with existing data?
9. How could a complex series of moves be increased in level by say 3dB?
10. Describe fader grouping.
11. How could EQ, for instance, be automated using an analogue mixing console?
12. How would EQ be automated using a digital mixing console?
13. What is 'recall'?
14. What advantages does a digital console have over an analogue console regarding recall?
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts?
18. What is the function of 'make up gain'?
19. How is a compressor usually connected to a mixing console to compress a single signal?
20. How is a compressor connected to a mixing console to compress the entire mix?
21. Explain 'ratio', in the context of compression.
22. Describe the difference between hard knee and soft knee.
23. What are 'breathing' and 'pumping'?
24. What happens if the release time is too long?
25. What does it mean if the gain reduction meter is showing frequent changes?
26. Describe the effect of compression on noise level.
27. Describe the function of the stereo link switch.
28. What is the side chain input?
29. Describe a typical use of the side chain input.
30. Is a noise gate usually effective on a mixed stereo signal?
31. Is a noise gate effective on a signal where the instrument plays all the time?
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
34. How many gates are often used in live sound: none, a few or many?
35. How is the noise gate connected to the mixing console?
36. What is the function of the Threshold control?
37. What is the function of the Range control?
38. Comment on the Attack, Hold and Release (Decay) controls.
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
40. Why are side-chain filters beneficial?
41. Comment on the use of an external key to improve the reliability of gating.
42. What is an expander?
43. Why are compressors and gates often used together?
44. Comment on envelope shaping using a noise gate.
45. Comment on gated reverb.
_________________
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Mon Sep 19, 2005 5:48 am |
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AndyBarber
Joined: 09 Sep 2005
Posts: 18
Location: North Wales |
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Posted: Mon Sep 19, 2005 3:48 pm Post subject: Week 4 - Questions
Andy Barber
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1. What is the function of mixing desk automation?
Automation on a mixing desk automatically controls fader (volume) levels so you don’t have to change parameters manually during a mix
2. Why might the faders have to be moved during the mix?
Different parts in a track require to be at various volume levels throughout the piece. Some may need to be reduced to allow other parts to be heard more clearly, others may be required to fade in/out of different sections
3. What aspects of mixing would normally be automated on an analogue console?
Analogue consoles rarely automate much more than channel volume levels
4. Comment on VCA vs. Moving Fader automation
Analogue consoles use one of two ways to automate fader levels
Motorised faders
Reproduces fader movements that you have previously made to a mix using motorised faders controlled by computer. Audio signal is routed through fader. Good visual feedback, fader level relates to actual gain setting of channel (always in absolute mode)
More expensive
Can introduce noise
VCA (voltage controlled amplifiers)
Here no physical audio passes through fader. Faders used to create DC voltage which is fed to automation computer so it can determine the fader position. Physical fader positions don’t move during playback so visual aid (computer monitor/LEDs) is required to monitor levels.
5. Describe write/update/read.
Each fader has 3 buttons that determines status of particular channel for mixing;
When in Write Mode the mix’s gains are controlled by engineer
Console is in Read Mode when mix data is played back, computer controlling gain
Channel’s automation can be re-recorded (updated) whilst playing back mix in read mode
Write to end, Allows fader setting to be continued from current position to end of mix without recording all way through track
6. How does an automated mix session start?
Data generated by manual fader movements is stored in computer. After creating a rough mix of all channels, individual channels can be replaced or modified to fine tune mix.. Once done all channels routed to master stereo recorder.
7. How would a section of automation data be re-recorded?
Channel can be flipped from Read to Write mode during playback allowing fader’s automation to be re-written, updating channels gain in real time. Activated by grabbing hold of fader during playback.. Releasing fader goes back to read mode. Some mixers have button on each channel which can arm individual channel for recording (record select) or punch in or out of write mode
8. How are automation 'punch-ins' blended smoothly with existing data?
Punch in/drop in, start new recording on track that already has a recorded part on it
Blended smoothly by automating the punch in button to start at a given time or musical bar
9. How could a complex series of moves be increased in level by say 3dB?
USING VCA
Initial writing of automation, use ‘Absolute mode’ (fader positions precisely corresponding to VCA levels).
After rough mix, most faders will be at a sensible position (near middle of their travel) others bad and at the bottom of their travel. ‘Trim mode’ allows faders to be moved to more convenient midway positions (ie. Increasing dB level) without VCA gain changing. Once done fader has more room to change gain up or down. Existing data isn’t replaced just modified. If fader now increased by 3dB then all recorded mix data on that channel is also increased by 3dB.
10. Describe fader grouping.
Fader channels can be grouped together in a subgroup for easier mixing. Once grouped, fader movement of a selected channel will cause levels of entire group to be adjusted. Relative level differences are maintained and with correct scaling, faders will reach bottom of their travel at same time..
11. How could EQ, for instance, be automated using an analogue mixing console?
External dynamics controllers are required. Auxiliary sends, send channels signal to external device which is then processed and sent back to mixer. Sent signal can be sent pre or post fader. EQ on external device can then be automated via MIDI sequencing
12. How would EQ be automated using a digital mixing console?
Modern digital consoles are design to automate virtually all aspects involved within a mixer. Many have built in effects and dynamics controls for every channel, who’s parameters can also be automated
Each channel has own independent Insert point allowing access of channels signal to be routed through internal dynamics controllers (compressor, noise gate, EQ etc)
13. What is 'recall'?
When a console is powered up it will display the same information as it had when it was powered down enabling the engineer to continue the project they were working on. By saving the consoles automation data different project setups can be recalled allowing different projects to be worked on at the same time.
“total recall” automation, every aspect of mixing console is memorized by computer and can be recalled at anytime, including EQ, pan effects sends, fader movements, on/off status for each channel
Snapshot, sometimes called a scene, is simply a set of automation data reflecting the state of the console fader gains and mutes at the time the snapshot was stored.
VCA automation is dynamic and completely separate to static recall automation
14. What advantages does a digital console have over an analogue console regarding recall?
With a digital consoles, parameter values and real time changes/automation of EQ, panning, insert/send effects and dynamics controls can also be recalled as well
NOTE:
Principles of any dynamic processor are based on an automatic, responsive control of amplitude using gain-reduction circuitry/software
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts? 16. What is the function of 'make up gain'?
Dynamics is the difference between the loud and quiet parts in a piece of music. Compressor controls the dynamics of a signal (originally controlled by engineer riding the faders on a mixing console).
A compressor will reduce the volume of the louder peaks in a signal. You can now use ‘make up gain’ to bring up the whole volume of the part by the amount you reduced it. This increases the quieter elements resulting in a more even and powerful tone. RMS power level (loudness) is increased
17. How is a compressor usually connected to a mixing console to compress a single signal?
Signal from a mixer channel is passed (pre-fader) to external compressor via insert point rather than a send. The whole signal is compressed and passed back to the mixer where its final volume can be controlled with the channels fader
18. How is a compressor connected to a mixing console to compress the entire mix?
Compressors can be placed at channel insert, bus inserts and master inserts
To compress an entire mix the compressor is connected to the master insert. Places compressor between the mixing consoles stereo master out signal and the master recording tape.
19. Explain 'ratio', in the context of compression.
The ‘threshold’ of a compressor is the level of input above which the signal will be compressed. The ‘Ratio’ defines the amount of compression (gain reduction) applied to the signal above the threshold value.
Higher ratio=Higher amplitude reduction
E.g. RATIO 2:1 Signal 2Db over threshold becomes 1Db over
So 20Db signal goes to 10Db over
RATIO 1:1 = NO COMPRESSION
RATIO infinity:1 = LIMITING (PREVENT AMPLIFIER FROM OVERLOADING)

20. Describe the difference between hard knee and soft knee.
Hard-knee compression, compression occurs exactly as signal hits threshold level
Soft-knee compression gradually applies compression as signal approaches threshold and after it has crossed the threshold.
“soft-knee” threshold features can create smooth and undetectable gain reduction, suitable for compressing whole mixes
Graph can be seen as thigh, knee and calf of a leg:

21. What are 'breathing' and 'pumping'?
Breathing/pumping sound may be heard when a quick change in gain is required (ie.Very short attack or release time). When sound level of drops below threshold there is no gain reduction and signal has a gain of 1. Signal is now closer to the noise level is system, so noise can be made audible.
http://www.harmony-central.com/Effects/Articles/Compression/
22. What happens if the release time is too long?
‘attack’ and ‘release’ control how rapidly the level detector follows the changing of audio signal. Fast attack applies full amount of compression almost immediately (can produce distortion). If release time is too long signal will not have time to increase the gain from low to high signal peaks. A flat amplitude response will be created clinging to lower peak values (or vice versa???). Release times longer than instruments decay will preserve instruments sound making it seem to last longer
(similar to speed of fader movements if volume ridded manually by engineer)

23. What does it mean if the gain reduction meter is showing frequent changes?
Meter compares processed and unprocessed sounds. Frequent changes in gain reduction means the incoming signal is varying in amplitude frequently as well. Signal dynamics may not be changing that dramatically but the compression could be set at a low threshold value.
24. Describe the effect of compression on noise level.
As stated compression decreases loud elements and boosts quiet elements in a signal. Low noise levels like system hum (noise floor of dodgy equipment) would be increased but loud noises like pops and clicks would be reduced
Note : Multi-band compressors usually used in MASTER stage. Can add clarity to a stereo mix, tighten up bass and impart an open, transparent quality to the high end.
27. Describe the function of the stereo link switch.
A stereo link is required to maintain the stereo image within a mix.
If loud signal present at left channel is compressed the reduction in volume would alter the stereo image
Stereo link switch allows compressor to link the two stereo channels forcing both sides to work together. Compression based on the average of the two input signals, or which ever is loudest at any time.
28. What is the side chain input?
A side chain is any signal that controls the action of a compressor
Audio signal split in two, one becoming side chain and controlling the compressor with the other being treated by the compressor. A side chain insert gives greater creative flexibility than if audio signal is controlling action alone.
29. Describe a typical use of the side chain input/insert.
Most common use of side chain insert is with EQ and is known as ‘frequency-conscious compression’
EQ audio signal sent to side chain
Frequencies can be cut to stop compressor reacting to particular frequencies or boosted to make compressor react more to particular frequencies.
e.g. Kick drum causing compressor to react most creating pumping of the drums as compression level rises after each kick drum and is then squashed again. Side chain EQ can be used to filter off some of the lower frequencies correcting problem (if pumping desirable can boost low frequencies to enhance effect)
30. Is a noise gate usually effective on a mixed stereo signal?
With a normal stereo signal yes, but stereo link must be used to ensure quality of sound is maintained
Noise gate won’t be effective on a finished, mastered stereo signal
31. Is a noise gate effective on a signal where the instrument plays all the time?
No. With an instrument playing all the time the signal wont drop significantly in amplitude. The noise levels are considerably lower in volume than of the instrument. With a threshold value just above that of the noise level, the signal level will never reach it and the gate will not kick in.
To reduce noise in this situation a FFT noise reduction system is required.
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
Yes, When the instrument stops playing the amplitude level will drop below a specified threshold point. When below this point the gate will kick in and mute/attenuate the signal, removing the noise.
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
As well as reducing noise levels, gating, especially used with side chaining, can reduce instrument bleed between the different drums leading to a clearer mix. Maintains spaciousness and background clarity
Snare and kick have short decay times (gating can be used effectively). Overheads pick up all sounds from drum kit and rarely have significant drops in amplitude when drummer is playing. Also cymbals have longer decay times. Therefore overheads don’t require gating
34. How many gates are often used in live sound: none, a few or many?
There are two types of noise, acoustical and electrical
Gating can reduce feedback, unwanted audio ambience sounds and bleeding from other instruments
Live sound/recording few gates may be required . Gates are great for amplified signals and drum tracks
35. How is the noise gate connected to the mixing console?
Usually connected to insert (pre-fader) of single channel/subgroup, not master out
Other effects produce noise so noise gate should be placed at end of effects chain
Delay and reverb placed after gate so sound trails off naturally not abruptly cut off
36. What is the function of the Threshold control? 37. What is the function of the Range control?
Noise gate is just compressor in reverse. Signals below threshold have gain reduction applied. Viewed from two points of view,1 quieter elements have been turned down or 2 dynamic range has been increased
Gate can be either open or closed
Below threshold gate is closed-applying a given amount of gain reduction to mute or attenuate input signal
Above threshold gate is open-no gain reduction applied, signal is at its original input level
Intensity of gain reduction can be controlled. Range control allows you to specify how much gain reduction is applied to signal when gate is closed. Range of around -96 dB will completely mute the signal
38. Comment on the Attack, Hold and Release (Decay) controls.
Speed and movement of gate is refined by Attack and release controls. They produce a softening effect which stops gate sounding too harsh and a side effect called ‘chattering’. (chattering caused when signal’s amplitude hovers round that of the threshold value)
Attack
With a fast attack the gate opens up quickly preserving the attack of the note. If too quick the gate may produce a click at the front of the note
Release
Controls the rate at which the gate closes. Usually as high as 250ms to preserve the natural decay of the note. Setting too fast can cause notes to be cut off and create chattering.
Hold
Another control to help remedy chatter. It keeps the gate open for a few more milliseconds after signal falls below threshold
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
The two channels can be linked in stereo or used as two separate mono sources
Stereo link used to apply twin channel gate to both channels of a stereo signal. When linked both channels forced to open and close at the same time. Without stereo link the two channels will change state at slightly different times producing undesired sound.
When stereo link is selected the range control remains active and applies the same attenuation to each stereo channel
40. Why are side-chain filters beneficial?
When multiple sounds are being recorded with separate microphones, it can be difficult to set the threshold values for each gate because of bleeding between instruments. A clean gated signal for each instrument required. Using side-chain filtering will transform the gate into a frequency-conscious device. The gates can be made to only respond to their specific instrument’s signal.
41. Comment on the use of an external key to improve the reliability of gating.
Side chain input is also known as the ‘Key’. The key is what the gate monitors to control the gain-reduction. Key is exact copy of input signal and can be EQ’d to remove accidental triggering. Side chaining will not affect timbre of output signal only the key.
42. What is an expander?
Very similar to a gate but with more sophisticated gain control. Expander has Ratio Control which has imparts a softer behaviour underneath the threshold. Expander is much more closer to reverse of compressor and can be used to restore dynamics of over compressed signals.
Most expanders are downward-signals below threshold are attenuated
Upward expanders-increase signal level above threshold
43. Why are compressors and gates often used together?
Using both together gives complete control over dynamic range both above and below threshold
44. Comment on envelope shaping using a noise gate.
Envelope shape is determined by amount of gain-reduction, attack, hold, decay and range control
45. Comment on gated reverb.
When reverberation is used a tail is produced that follows the signal. When a noise gate is used the tail is cut off after a few milliseconds, rather than being allowed to naturally decay.
http://www.soundonsound.com/sos/may01/articles/advancedgating.pt2.asp
http://www.audiomasterclass.com/netscape4/articles/automatedmixing.html
http://www.soundonsound.com/sos/jan00/articles/mix.htm
http://www.tvtechnology.com/features/Inside-Audio/Moulton.shtml
http://www.cs.tut.fi/~albert/Dev/pucrunch/packing.html
http://www.ife.ee.ethz.ch/music/audio/aes_html/node1.html
http://www.harmony-central.com/Effects/Articles/Expansion/
http://homerecording.about.com/od/techniques/a/basic_comp.htm
http://www.ks1075.com/local_love/article02.html
http://www.music.gla.ac.uk/HTMLFolder/Resources/StudioSite/audio/desk/desktut.html
http://www.audiomasterclass.com/units/body/18noisegatebody.html
http://www.transom.org/tools/basics/200302.processing.jtowne.html
http://www.pcmus.com/compressors.htm |
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Thu Sep 22, 2005 9:03 am |
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thx1138
Joined: 07 Jan 2005
Posts: 21
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1. What is the function of mixing desk automation?
The function of mixing desk automation is basically to control the faders and to make life easier for the recording engineer. Even the most dextrous engineer would have problems moving 16 plus faders at the same time.
The basic aim is to aid the engineer during mixdown when the amount of faders controlled becomes too much for one person to adequately control.
2. Why might the faders have to be moved during the mix?
The faders might have to be moved during a mix to fade parts in or out and to adjust the levels of individual parts.
3. What aspects of mixing would normally be automated on an analogue console?
The aspects of mixing that would normally be automated on an analogue mixer are the channel faders and the channel mutes.
4. Comment on VCA vs. Moving Fader automation.
VCA fader automation is when information regarding fader positions is stored and the used to control a voltage controlled amplifier, in some cases fader information could then be shown on a computer screen. VCA automation does not physically move the faders so the fader's position may not always correspond with the gain of that particular channel.
Moving fader automation also stores information regarding fader gain but uses the data to actually physically move the faders position using a motor.
5. Describe write/update/read.
Write is when the VCA gain corresponds directly to the fader position. This is when the faders moved by the engineer have their positions and movements recorded.
Read is when VCA gain is controlled by the recorded data from a previously stored mix.
Update is when the VCA gain is controlled by a previously stored mix and current fader position. This is when an existing mix is altered by the engineer, so parts can be updated and rewritten.
6. How does an automated mix session start?
An automated mix session would start by enabling automation and selecting the tracks you wish to automate, then any fader movements will be recorded as data after 'play' has been pressed.
7. How would a section of automation data be re-recorded?
A section of automation could be re-recorded by using the update mode of the mixer so that a previously stored mix can be recalled and any changes made by the engineer to the section of automation will be saved.
8. How are automation 'punch-ins' blended smoothly with existing data?
Punch-ins are blended smoothly with existing data by means of cross fading from the original track to the punch-in and back again.
9. How could a complex series of moves be increased in level by say 3dB?
A complex series of moves can be increased in volume by 3dB by using a master fader to control the gain of a set of grouped faders assigned to the master fader. The master fader could be set to affect all of the other tracks or a group of specific tracks on the mixer.
10. Describe fader grouping.
Fader grouping is when a selection of tracks are grouped together such as guitar tracks or drum tracks so they can be controlled by one master fader. The level of the entire group can then be controlled by moving just the master fader for that group instead of having to move the faders for each track in the group individually.
11. How could EQ, for instance, be automated using an analogue mixing console?
The EQ on an analogue mixer could be automated in much the same way as a fader, by using a VCA or the movements of a fader itself.
12. How would EQ be automated using a digital mixing console?
A digital mixer has a facility known as snapshot. Any EQ changes can then be saved using snapshot and recalled as a mix is played through.
13. What is 'recall'?
Recall is a facility whereby the movement of faders and other mixer controls such as EQ can be recalled at any position during a mix.
14. What advantages does a digital console have over an analogue console regarding recall?
With a digital mixer it is possible to take snapshots of the parameters of every control on the mixer which can then be stored and recalled instantly. With an analogue mixer recall is a means of telling the operator where the controls should be at any given point in the mix and then leaving the operator to reset the controls themselves.
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts?
A compressor acts upon loud signals by bringing them down closer to the quieter signals; it is a tool for altering the dynamic range of an audio signal.
The compressor reduces the difference between the loudest and quietest parts of an audio signal by bringing down the peaks of the loudest parts so they are closer to the quietest parts and then boosting the entire signal to make it seem louder and fuller. A compressor can also add punch and 'pump' to an audio signal.
18. What is the function of 'make up gain'?
Make up gain is used to compensate for the compressor lowering the louder parts. Make up gain raises the level of the audio signal back to the level of the original peaks.
19. How is a compressor usually connected to a mixing console to compress a single signal?
The compressor is usually attached to a mixer to compress a single signal via a mixer channel insert point.
20. How is a compressor connected to a mixing console to compress the entire mix?
A compressor is connected to a mixer to compress the entire mix via an insert point or the compressor could be attached to the output bus of the mixer.
21. Explain 'ratio', in the context of compression.
In the context of compression, ratio controls the amount of signal reduction. A ratio of 5:1 would mean for every 5dB the signal exceeds the threshold (the level at which the compressor will start to affect the signal) it will be attenuated so the signal only increases by 1dB.
22. Describe the difference between hard knee and soft knee.
Knee is the response curve of a compressor. Soft knee is when the compression begins slowly as the audio signal nears the threshold level and smoothes the transition from an uncompressed signal to a compressed one. Hard knee is when the compression begins and ends exactly at the threshold level.
23. What are 'breathing' and 'pumping'?
Breathing is when the noise floor of a signal rises and falls drastically; an example could be a heavily compressed noisy drum track and the noise level 'breathing' in between drum hits. Increasing release time can help to reduce this so the noise level has no time to breathe between compressed signals.
Pumping is when lower level signals are lost after a peak as the compressor stops reducing gain. It is where the low-level signals slowly return to their original signal level.
24. What happens if the release time is too long?
Release is the amount of time after a signal falls beneath the threshold level that it takes for the compressor to stop compressing.
If the release time is too long then too much of the signal beneath the threshold level will be compressed. Lower level signals after the peaks will be lost as the compressor slowly stops reducing gain.
25. What does it mean if the gain reduction meter is showing frequent changes?
If the gain reduction meter is showing frequent changes it shows that compression is occurring on the higher area of the dynamic range of the signal and that the signal is above the threshold.
26. Describe the effect of compression on noise level.
When a compressor is making changes to a signal the noise level will rise and fall along with the level of the signal and the noise level can cause breathing to occur.
27. Describe the function of the stereo link switch.
The stereo link switch ensures that both channels of a signal are compressed to the same extent.
28. What is the side chain input?
The side chain input is a secondary input on a compressor that allows control, according to the side chain input, over the functions of the compressor.
29. Describe a typical use of the side chain input.
Some typical used for the side-chain input are ducking and de-essing.
Ducking is when the level of one signal is controlled by another. For instance when a voice over is required the background music can be made to 'duck' in volume.
De-essing is when the effects of sibilance in a vocal signal is reduced, the compressor removes the high frequencies of the voice such as 'sss', 'chhh' and 'fff' sibilants.
30. Is a noise gate usually effective on a mixed stereo signal?
A noise gate is not usually effective on a mixed stereo signal; it is more effective on a single unmixed signal from an instrument.
31. Is a noise gate effective on a signal where the instrument plays all the time?
Without periods of silence a noise gate is not effective as with an instrument playing all the time it will probably be at a fairly constant volume, silence would be an indicator that the gate should be closed and unwanted noise gated out.
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
With one single noisy signal with gaps in the playing it is the ideal 'environment' for a noise gate to be applied as it is the gaps in the playing where unwanted noise can occur and be gated out by the noise gate.
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
It is often considered beneficial use a noise gate on some or all of the mics on a drum kit (except the overheads) so that unwanted signal bleed between mics can be removed. When a particular drum is not being played the gate will be shut so that other drums being played will not be picked up.
34. How many gates are often used in live sound: none, a few or many?
In a live situation any number of gates could be used. Each instrument could have a gate attached to any mics picking up its signal.
35. How is the noise gate connected to the mixing console?
A noise gate would be attached to a mixing desk via a channel insert point.
36. What is the function of the Threshold control?
The function of the threshold on a noise gate is to set the point at which the gate opens and closes. Signals beneath the threshold close the gate and those signals are gated out, signals above the threshold are let through.
37. What is the function of the Range control?
Some gates do not mute the signal completely when it falls beneath the threshold. Instead the signal is attenuated by an amount defined by the user. Range control is used to control the amount of attenuation, the amount the signal is reduced by.
38. Comment on the Attack, Hold and Release (Decay) controls.
Attack is the speed at which the gate opens, release is the speed at which the gate closes.
Release time should be matched to the sound signal being gated so that sounds remain natural.
Hold is when the user can specify the minimum time that the gate will be open for. Sounds around the threshold level could cause 'chattering' where the gate opens and closes rapidly.
Hold controls the minimum amount of time the gate will remain open for when the level of a signal exceeds the threshold so that it is held open for at least that amount of time specified by the hold level before starting to close again when a signal falls beneath the threshold level.
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
If a stereo signal was gated but the stereo link function was not selected then each channel would be gated independently. That is to say if the signal on the left side fell below the threshold level but the one on the right didn't then only the left channel would have a closed gate whilst on the right the gate would remain open.
40. Why are side-chain filters beneficial?
Side-chain filters are beneficial as you can specify what actually triggers the gate. If you were gating drum tracks for instance and wanted to gate the snare drum track but spill from the kick drum or hi-hat is also triggering the gate then, you could EQ the side-chain signal to roll off the low frequencies (in the case of the kick drum) or high frequencies (in the case of the hi-hat), so that the gate is less likely to be triggered by the kick drum or hi-hat and more likely to only open for the snare drum.
The EQ would also only affect the side-chain signal and not the actual gated sound.
41. Comment on the use of an external key to improve the reliability of gating.
Some gates have an external side-chain input, which is known as the 'key' input. Several noise gates can be made to operate in the same way by sending the same signal to each of their key inputs.
If you had a group of backing singers, all singing the same thing on separate tracks but some of the not singing quite in time with the rest of the singers. You could gate all the parts by feeding the key inputs of all the gates with the signal from the track with the best timing. This could improve the perceived quality of the overall performance.
This could also be used to tighten up bass guitar tracks by feeding the key input on the gate with the signal from the kick drum which could prevent any bass notes from starting before the kick drum sounds.
42. What is an expander?
An expander is basically the opposite of a compressor. Instead of working on signals above the threshold level it works on the signals below it. The signal is attenuated by ratio setting.
For example: if a ratio setting of 1:4 is selected then for every dB the signal falls by, the output signal will drop by 4dB. This is useful for bringing back more natural dynamics to an over compressed signal.
43. Why are compressors and gates often used together?
When a signal is compressed the noise fall of the signal rises and falls along with the compressed signal, so a noise gate can often be used together with a compressor to compensate for the raised noise floor. The gate can be set to close when the raised noise floor becomes most obvious.
44. Comment on envelope shaping using a noise gate.
You can shape the envelope of a signal going through a noise gate by connecting another sound to the external key input. The dynamic envelope of the signal going into the external key will be imposed on the signal going through the gate.
The attack, release and hold functions will also shape the envelope of the signal passing through the gate by controlling how fast the gate opens and closes and the minimum amount of time the gate will remain open before closing again.
45. Comment on gated reverb.
Gated reverb is the use of a noise gate to cause a sudden termination of a reverberation effect without allowing for the normal decay signal to complete. This can give a sound an unnatural, industrial timbre.
Sound and Recording
Computer Music issue 89
www.harmony-central.com/effects/articles/misc/pumping-and-breathing.pdf
www.humbuckermusic.com/comex.html
www.soundonsound.com/sos/apr01/articles/advanced.asp
www.songstuff.com/articles.php?selected=44
_________________
AcousticalWeaponsDivision/Alex |
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Thu Sep 22, 2005 10:38 am |
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Rbro
Joined: 07 Sep 2005
Posts: 12
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1. What is the function of mixing desk automation?
This lets the user programme in some, normally manual, functions. e.g. on an automated mixing desk the faders can be set to move automatically during playback. This allows the user to be free for another part of the mix.
2. Why might the faders have to be moved during the mix?
Faders may move in a mix to allow one part to be heard over another or to fade in or out.
3. What aspects of mixing would normally be automated on an analogue console?
The channel levels, mutes and master output levels are all usually automated on a analogue console.
4. Comment on VCA vs. Moving Fader automation.
VCA stands for volume controlled amplifier. The downside to VCA is you can’t physically see the volume levels as you would with a fader (unless you can see on the computer). A fader is more visual for the engineer.
5. Describe write/update/read.
Write/Update/Read refers to programming an automated mixing desk.
Write: When the users programmes in some sets and levels
Update: The option to change previous programmed moved on a later take.
Read: The computer is in control and plays what has been programmed.
6. How does an automated mix session start?
If the engineer has a ‘snapshot’ of a mixer position it is easy to start at this point. A snapshot is a setting of the mixing console that is remembered by a computer and can be set to how it was previously. Other than this a good starting point is the channel mutes. For a better, clearer mix the engineer would go through each track and set the automated mute to the track whenever there is no part playing.
7. How would a section of automation data be re-recorded?
If you change the read to write during playback you can record over existing automated data.
10. Describe fader grouping.
Fader grouping refers to one instrument or section that has multiple faders. Once individual faders are set the engineer can group the faders together so they will move as one. e.g. the drum faders can be grouped to allow the entire drum sound to be made louder/softer.
13. What is 'recall'?
Recall is the ability to get back all the mix’s automated information day, weeks or months after the mixing time. It is saved in a computer memory.
14. What advantages does a digital console have over an analogue console regarding recall?
A digital console can remember every detail of the mix (even effects) this means no additional setting up is required when you come back to your mix. There would be some setting up with an analogue console, effects etc. The digital mixer recall is also faster, you can try your original mix, change it and then revert back.
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts?
A compressor acts upon loud signals. Depending on the setting (threshold) a compressor will limit loud signals so that the volume is within a certain range dB(defined by the user). It is commonly believed that a compressor boosts low signals but this is actually caused by the make up gain.
18. What is the function of 'make up gain'?
Make-up gain come into use when the compressor is being used. It increases gain taken away by the compressor.
19. How is a compressor usually connected to a mixing console to compress a single signal?
A compressor is usually connected using an insert point.
20. How is a compressor connected to a mixing console to compress the entire mix?
You could connect the compressor to an aux. and turn the aux. up on all the channels.
21. Explain 'ratio', in the context of compression.
Ratio refers to how much compression is used on a signal, it is set by the user. If the input signal to the compressor is 20dB and the output signal is 10dB the ratio is 2:1. A ratio of 5:1 is common for instruments/vocals.
22. Describe the difference between hard knee and soft knee.
A hard knee compressor kicks the moment the threshold is crossed and compresses the signal. A soft knee compressor gradually builds up from 1:1 to the set ratio. The soft knee starts to reduce the gain as the volume approaches the threshold.
23. What are 'breathing' and 'pumping'?
Breathing and pumping are ‘side’ effects of a compressors release time. If the release time is fast you’ll hear the volume coming back up after the compressor is off, it produces a breathing sound. This sound is sometimes used as an effect.
24. What happens if the release time is too long?
Too long a release time will produce a pumping effect. This sound comes fro the lower sound levels slowly returning to normal.
25. What does it mean if the gain reduction meter is showing frequent changes?
This means that the compressor is being used a lot. The gain reduction meter shows how much gain the compressor is taking off the signal. This would mean there is a lot of sound crossing the threshold and it may need to be reajusted.
26. Describe the effect of compression on noise level.
A compressor limits loud signals but boosts quiet signals. If the compressor boosts a quiet signal the ground noise will also increase and therefore increase the noise level.
27. Describe the function of the stereo link switch.
A stereo link switch links the controls for both left and right channels. You wouldn’t have to set the channels individually when using a compressor or gate.
28. What is the side chain input?
A side chain input is an input which will start the device working. e.g. a kick drum in a bass compressor will activate the compressor.
29. Describe a typical use of the side chain input.
A bass drum could be used to activate a bass guitar compressor. This way the two instruments will sound more in sync.
30. Is a noise gate usually effective on a mixed stereo signal?
No, a mixed signal has some instruments at different volumes and would not be effective
31. Is a noise gate effective on a signal where the instrument plays all the time?
A noise gate cuts out unwanted low level noise, mainly during pauses. It would not be effective on a signal where the instrument plays all the time.
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
Yes, a noise gate take out hiss or spill (anything under the threshold) during gaps in the music.
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
When miking drums noise from the other drums can ‘spill’ over onto the wrong mic. A gate would help cut out the unwanted spill.
35. How is the noise gate connected to the mixing console?
A noise gate is connected to the console using an insert point or aux.
36. What is the function of the Threshold control?
The threshold control sets the level at which the noise gate will close cutting off all sounds lower than that.
37. What is the function of the Range control?
The range control is set by the user. This control sets how far the gate is closed. If it is fully closed all noise under the threshold is cut out.
38. Comment on the Attack, Hold and Release (Decay) controls.
Attack: How long it takes for the gate to close once the threshold has been crossed.
Hold: How long the gate stays closed after attack
Release: How long it takes for the gate to open after attack and hold.
Although this can be used to set up a gate many musicians use these controls as effects e.g. The hold and release can improve sustain on a guitar
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
Stereo link lets you control the signal as one if you didn’t have the link function selected the gate would open and close differently on the two signals.
42. What is an expander?
An expander increases volume. It is made to increase the high and low level signals.
43. Why are compressors and gates often used together?
As a compressor boosts a quiet signal it also boosts the floor noise. A gate would help to cut the floor noise. Again, both of these processors rely on correct setting to obtain the best sound.
45. Comment on gated reverb.
Reverb recreates the acoustics of a room. As the sound is dying away the gate would close (at the threshold level) and cut off the reverb. |
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Fri Sep 23, 2005 2:57 pm |
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Rbro
Joined: 07 Sep 2005
Posts: 12
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1. What is the function of mixing desk automation?
This lets the user programme in some, normally manual, functions. e.g. on an automated mixing desk the faders can be set to move automatically during playback. This allows the user to be free for another part of the mix.
2. Why might the faders have to be moved during the mix?
Faders may move in a mix to allow one part to be heard over another or to fade in or out.
3. What aspects of mixing would normally be automated on an analogue console?
The channel levels, mutes and master output levels are all usually automated on a analogue console.
4. Comment on VCA vs. Moving Fader automation.
VCA stands for volume controlled amplifier. The downside to VCA is you can’t physically see the volume levels as you would with a fader (unless you can see on the computer). A fader is more visual for the engineer.
5. Describe write/update/read.
Write/Update/Read refers to programming an automated mixing desk.
Write: When the users programmes in some sets and levels
Update: The option to change previous programmed moved on a later take.
Read: The computer is in control and plays what has been programmed.
6. How does an automated mix session start?
If the engineer has a ‘snapshot’ of a mixer position it is easy to start at this point. A snapshot is a setting of the mixing console that is remembered by a computer and can be set to how it was previously. Other than this a good starting point is the channel mutes. For a better, clearer mix the engineer would go through each track and set the automated mute to the track whenever there is no part playing.
7. How would a section of automation data be re-recorded?
If you change the read to write during playback you can record over existing automated data.
10. Describe fader grouping.
Fader grouping refers to one instrument or section that has multiple faders. Once individual faders are set the engineer can group the faders together so they will move as one. e.g. the drum faders can be grouped to allow the entire drum sound to be made louder/softer.
13. What is 'recall'?
Recall is the ability to get back all the mix’s automated information day, weeks or months after the mixing time. It is saved in a computer memory.
14. What advantages does a digital console have over an analogue console regarding recall?
A digital console can remember every detail of the mix (even effects) this means no additional setting up is required when you come back to your mix. There would be some setting up with an analogue console, effects etc. The digital mixer recall is also faster, you can try your original mix, change it and then revert back.
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts?
A compressor acts upon loud signals. Depending on the setting (threshold) a compressor will limit loud signals so that the volume is within a certain range dB(defined by the user). It is commonly believed that a compressor boosts low signals but this is actually caused by the make up gain.
18. What is the function of 'make up gain'?
Make-up gain come into use when the compressor is being used. It increases gain taken away by the compressor.
19. How is a compressor usually connected to a mixing console to compress a single signal?
A compressor is usually connected using an insert point.
20. How is a compressor connected to a mixing console to compress the entire mix?
You could connect the compressor to an aux. and turn the aux. up on all the channels.
21. Explain 'ratio', in the context of compression.
Ratio refers to how much compression is used on a signal, it is set by the user. If the input signal to the compressor is 20dB and the output signal is 10dB the ratio is 2:1. A ratio of 5:1 is common for instruments/vocals.
22. Describe the difference between hard knee and soft knee.
A hard knee compressor kicks the moment the threshold is crossed and compresses the signal. A soft knee compressor gradually builds up from 1:1 to the set ratio. The soft knee starts to reduce the gain as the volume approaches the threshold.
23. What are 'breathing' and 'pumping'?
Breathing and pumping are ‘side’ effects of a compressors release time. If the release time is fast you’ll hear the volume coming back up after the compressor is off, it produces a breathing sound. This sound is sometimes used as an effect.
24. What happens if the release time is too long?
Too long a release time will produce a pumping effect. This sound comes fro the lower sound levels slowly returning to normal.
25. What does it mean if the gain reduction meter is showing frequent changes?
This means that the compressor is being used a lot. The gain reduction meter shows how much gain the compressor is taking off the signal. This would mean there is a lot of sound crossing the threshold and it may need to be reajusted.
26. Describe the effect of compression on noise level.
A compressor limits loud signals but boosts quiet signals. If the compressor boosts a quiet signal the ground noise will also increase and therefore increase the noise level.
27. Describe the function of the stereo link switch.
A stereo link switch links the controls for both left and right channels. You wouldn’t have to set the channels individually when using a compressor or gate.
28. What is the side chain input?
A side chain input is an input which will start the device working. e.g. a kick drum in a bass compressor will activate the compressor.
29. Describe a typical use of the side chain input.
A bass drum could be used to activate a bass guitar compressor. This way the two instruments will sound more in sync.
30. Is a noise gate usually effective on a mixed stereo signal?
No, a mixed signal has some instruments at different volumes and would not be effective
31. Is a noise gate effective on a signal where the instrument plays all the time?
A noise gate cuts out unwanted low level noise, mainly during pauses. It would not be effective on a signal where the instrument plays all the time.
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
Yes, a noise gate take out hiss or spill (anything under the threshold) during gaps in the music.
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
When miking drums noise from the other drums can ‘spill’ over onto the wrong mic. A gate would help cut out the unwanted spill.
35. How is the noise gate connected to the mixing console?
A noise gate is connected to the console using an insert point or aux.
36. What is the function of the Threshold control?
The threshold control sets the level at which the noise gate will close cutting off all sounds lower than that.
37. What is the function of the Range control?
The range control is set by the user. This control sets how far the gate is closed. If it is fully closed all noise under the threshold is cut out.
38. Comment on the Attack, Hold and Release (Decay) controls.
Attack: How long it takes for the gate to close once the threshold has been crossed.
Hold: How long the gate stays closed after attack
Release: How long it takes for the gate to open after attack and hold.
Although this can be used to set up a gate many musicians use these controls as effects e.g. The hold and release can improve sustain on a guitar
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
Stereo link lets you control the signal as one if you didn’t have the link function selected the gate would open and close differently on the two signals.
42. What is an expander?
An expander increases volume. It is made to increase the high and low level signals.
43. Why are compressors and gates often used together?
As a compressor boosts a quiet signal it also boosts the floor noise. A gate would help to cut the floor noise. Again, both of these processors rely on correct setting to obtain the best sound.
45. Comment on gated reverb.
Reverb recreates the acoustics of a room. As the sound is dying away the gate would close (at the threshold level) and cut off the reverb. |
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Fri Sep 23, 2005 2:58 pm |
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Polarman
Joined: 24 Jun 2005
Posts: 55
Location: Barbados |
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1. What is the function of mixing desk automation?
The most common reason to have mixing desk automation is to store the faders’ position against time to be able to bring the mix back at a later moment. For the engineer this means that he/she can handle more faders at a time then normally for one person. The engineer can also concentrate on one part of the mix at a time and slowly build up the final mix and refine it. There are different levels of mixing desk automation from just storing the position of the faders and use this data to control the gain of a VCA (Voltage Controlled Amplifier) or digital attenuator to total automation systems that can store and restore all functions of a mixer.
2. Why might the faders have to be moved during the mix?
There are two reasons depending on which type of automation you are using.
a) If you console only stores the fader positions the faders’ move with a motor when playing the mix. The actual VCA level is determined of the positions of the fader.
b) If you have a mixing desk that doesn’t have the ability to directly move the faders from recorded fader levels your faders will not be showing what the channels levels are. Then you have to move the faders to the actual values of the channel (VCA) this can be shown with “null” LED, little light on the fader that show which direction the fader should be dragged to make its position corresponding the VCA value. Normally when you drag the faders and it reaches the VCA value the LED the lights go out. Here sometimes the faders changes from read to write mode.
3. What aspects of mixing would normally be automated on an analogue console?
On an automated analogue mixing console the faders would be automated. Other things that would be automated would be channel mutes and sometimes effect send/return mutes.
4. Comment on VCA vs. Moving Fader automation.
There are normally two ways to automate fader levels on mixing consoles. You can have motorised faders reproduce fader moves you did in the earlier mix or you can use VCA (Voltage Control Amplifiers) which are controlled by normal faders. There are two main differences between these two:
a) Most moving-fader systems route the audio signal through the fader in the conventional manner. In the VCA the faders are just used to produce a DC voltage that is read by the automation computer to determine the fader position system, no audio passes through.
b) With moving faders system you always have a visual contact with your mix since the faders move according to you recorded movements. With the VCA systems you don’t have that visual feedback of the actual levels unless you use a system to which a computer screen can be connected to show both the physical position of the faders and the virtual fader level corresponding to the VCA gain. Systems with no screens usually have a system of LEDs to tell the user which way to move the fader in order to match the VCA level. When a match is achieved, the LEDs goes out or they may both come on.
5. Describe write/update/read.
An automated mixing console can work in different modes normally each channel can take one of the three modes.
Write
This is the mode where the actual channel levels, mutes, sends etc are written. What is written depends on your mixing console and if it is a moving fader or VCA. If you have a VCA it can be good to use absolute mode so the faders actually show the VCA levels. The engineer has control over the levels and controls.
Update
This is a combination of a previously written mix and the current fader position/VCA level. When in this mode, mix data that's written doesn't replace the existing data but instead modifies it. Used to fine tune the mix.
Read
The Faders position or the VCA gain is controlled by the recorded data from a previously recorded mix.
6. How does an automated mix session start?
First of all its good to start any mixing session as a mix session without automation. Its good to do as much as possible before thinking of automation Balance the sounds, set panning, set EQ, master effects, set up delays, compression tweaks etc. If you need any fader groups set them up. Save this basic mix when you are ready if you have that kind of system. Starting too early with automation you can easily loose control of what really is automated. A good first step using the automation is to write all the mutes on each track (if you haven’t got rid of material that shouldn’t be there before). This will pay off in that you will come up with a much cleaner mix.
7. How would a section of automation data be re-recorded?
To re-record a section of automation you must put the console in write mode or alternatively in up date mode.
8. How are automation 'punch-ins' blended smoothly with existing data?
If you have motorised faders the mixing console would normally switch to write mode when you touch the faders so no jump will happen.
With a VCA system is important to calibrate the faders to the null indicator before going into write mode, if you are using up date mode only relative changes will occur.
9. How could a complex series of moves be increased in level by say 3dB?
To increase a complex series of moves by 3dB you can assign these channels to a fader group. Raise master group fader by 3dB.
10. Describe fader grouping.
Fader grouping means to let one fader control the level of many slave channels. This is normally done on recorded horns, background vocals etc. This means that the engineer has to control less faders at a time and it’s also convenient when many channels are carrying channels that can be faded up and down together. Even if a number of channels are grouped it is still possible to adjust the levels individually. There are two solutions to this which give quite different results:
Audio grouping
Here the actual console has a group output. All the channel outputs that are assigned to the group fader will be summed up. The summed signal will then be routed to the main output.
Control grouping
Here the levels of the grouped faders controlled by the assigned group fader. But their outputs remain separate. This is the same as a hand would move all the faders at the same time. The achieve this controlled groping VCAs is normally used. This means that the fader will carry DC instead of audio. In an automated system any fader can be assigned as a group master.
11. How could EQ, for instance, be automated using an analogue mixing console?
On an automated analogue mixing console normally only the channel faders and the channel mutes are automated. You could duplicate the tracks with different EQ settings on desirable amount of tracks and depending on your track ability. You can then use mute automation to switch between the tracks. This way you would only get a certain amount of automation.
12. How would EQ be automated using a digital mixing console?
A digital mixing console normally has the ability to take snapshots. You can take snapshots on different EQ settings and recall them during the mix.
13. What is 'recall'?
Most automated desks will be able to store a number of automation snapshots in their internal memory, and these may be called up at any time during a mix as part of the normal automation process. Further refinements include the ability to isolate individual channels so they're not affected when a snapshot is recalled.
14. What advantages does a digital console have over an analogue console regarding recall?
In a digital mixing console everything is automated and saved. When you do a recall everything is brought up exactly as it was when you saved. When you are using a analogue mixer there a lot of controls that are not automated. Everything that it’s not automated has to be written down, some engineer take picture or you can actually use a small tape recorder and talk through all the settings saving them on tape.
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts?
A compressor reduces the dynamic range which means to reduce the difference in level between loud parts of the signal and quiet parts. It does this by reducing the level of the loud sections.
18. What is the function of 'make up gain'?
Applying compression reduces the highest levels, reducing the dynamic range. Because the peak level of the signal is now lower compared to the original peak level, make-up gain is must be added to restore the original peak level. In this way using compression you get a much more controlled and usable sound.
19. How is a compressor usually connected to a mixing console to compress a single signal?
A compressor is connected to the mixer on an insert send and brought back to the channels insert return. In this way the compressor is only affected by the input gain.
20. How is a compressor connected to a mixing console to compress the entire mix?
To compress the entire mix the compressor can be connected to the main stereo output's insert point.
21. Explain 'ratio', in the context of compression.
The ratio in context of compression means that the higher the ratio, the greater the compression (signal reduction). Ratio is the 'strength' of compression above the threshold level. If the ratio is set at 4:1, it means that when the signal is above the threshold level, when the input signal rises by 4 dB, the output signal rises by 1 dB.
22. Describe the difference between hard knee and soft knee.
This is a characteristic of certain designs of compressors and usually not a control or parameter. Some compressors have an adjustable knee, variable between hard and soft.
The point where the slope of the compressors curve changes (set by threshold level) is known as the Knee. With a soft knee gain reduction is brought in progressively, signals which only just exceed the threshold level are compressed at a low ratio, the ratio increasing the higher the signal level. On a hard knee the full compression ratio starts directly when the signal reaches the threshold.
23. What are 'breathing' and 'pumping'?
Release: how fast the gain is restored to normal levels after the input signal falls below the threshold. If the release time is too short, background noise can cause effects often known as 'breathing' and 'pumping'.
24. What happens if the release time is too long?
If the release time is too long, the signal will not be compressed, but simply reduced in level.
25. What does it mean if the gain reduction meter is showing frequent changes?
The gain reduction meter will show how much compression is going on. The faster the meters move up and down, the harder the compressor is working. If it stays steady, there is little active compression, just a steady-state reduction in level.
26. Describe the effect of compression on noise level.
Compression has the effect to increase the noise level. This is because the peaks of the signal are brought down in level, bringing them closer to the noise floor. Then when make-up gain is used to bring the signal level back up again, the noise floor raises.
27. Describe the function of the stereo link switch.
When using compression on a stereo signal the stereo link has to be activated. Otherwise the channels will get different amount of gain reduction. If this is not done, a loud signal in one channel will cause that channel to be lowered in level while the other stays the same. Any signal that is panned center in the mix will move in the stereo image towards the unchanged channel. With stereo link selected, the stereo image not be shifted.
28. What is the side chain input?
In addition to the normal signal input, a compressor has a 'side chain' input. The side chain allows the signal passing through the unit to be controlled by the dynamics of another separate signal.
29. Describe a typical use of the side chain input.
De-essing is an important compression technique using the side chain. The microphone channel is routed to a group with the compressor patched into the group insert points. The microphone channel is also paralleled into another channel via the line input. The signal in the second channel is equalized so that high frequencies in the sibilant range are boosted. This channel is fed via an auxiliary output to the compressor side chain input.
Now, the compressor will react whenever there is a sibilant, reducing the gain for the duration of the sibilant and cleaning up the vocal sound.
30. Is a noise gate usually effective on a mixed stereo signal?
A noise gate on a stereo channel is usually not effective. Since most tracks are recorded in mono. But if you for example have an old guitar track with a stereo effect like chorus, you should use stereo link so both channels are forced to open and close at the same time.
31. Is a noise gate effective on a signal where the instrument plays all the time?
There is no benefit in using it unless there are sections of silence
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
Yes, this is often used with the electric guitar, where the amplifier is likely to be noisy. In this situation, what the noise gate does is detect when the signal level is high, when it assumes that the guitar is playing, and opens fully to allow the signal through unimpeded. When the gate detects that the signal level is low, it assumes that the guitarist is not playing and closes completely, blocking off the noise.
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
The normal way of miking up drums demands a mic on each drum, a mic on the hihat and two overhead mics. The problem with this is that the mics are all so close together that each mic picks up every instrument of the kit to an extent, as well as its own instrument. To make it more focused, all the mics except the overheads are gated so that each channel is only open when the drum is actually sounding.
34. How many gates are often used in live sound: none, a few or many?
Normally in a live situation every mic is gated.
35. How is the noise gate connected to the mixing console?
A noise gate is connected to the insert point of the mixing console. As with equalizers and compressors, gates are not used via the aux send and return loop.
36. What is the function of the Threshold control?
The Threshold control sets the level at which the gate will decide whether to open or close. When the signal is above the threshold, the gate will be open. When it is below the threshold, the gate will be closed. IT is important to set this level right and make sure that when the musician plays, the first note gets through, right from the initial attack. Also, when the musician stops, the decay of the last note is able to fade away before the gate closes.
37. What is the function of the Range control?
The Range control sets the degree of attenuation when the gate is closed (signal lower then threshold. Range is set manually. Normally gates are set to maximum attenuation. Range control is important when gating drum recordings.
38. Comment on the Attack, Hold and Release (Decay) controls.
The Attack and Decay controls are used to shape the envelope of the sound. Attack determines the speed which the gate opens and release the speed by which the gate closes.
The Hold control sets a time period during which the gate will remain fully open, even though the signal has just dropped below the threshold. Hold is the minimum amount the gate will be open. This is to reduce uncertainty when the gate doesn't know for sure whether it is supposed to be open or closed and it will change state rapidly a number of times.
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
If Stereo Link is left off for a stereo signal the left and right channels would be gated independently. So sometimes you would hear the right channels when it reaches the threshold and some times you would hear the left channel when it reaches the threshold. It doesn’t matter how carefully you set the threshold controls the channels will change state at slightly different times.
40. Why are side-chain filters beneficial?
noise gate has a 'side chain' signa, ust like a compressor, that is used to control the behavior of the processed signal. On a gate this is normally called the trigger, or key signal. Side chain filters are normally put in there end positions so they have no effect. A side chain filter can be used to just let a specific frequencies open a gate. For example to stop the hihat from opening the gate on the snare mic, simply filter out the high frequencies from the key. The snare is sufficiently rich in low frequencies that it will still open the gate, but the lesser LF content of the hihat is not enough to do the same. If there was a mic on the hihat suffering from the same problem, then the low and mid frequencies could be filtered out of the key, and the rich high frequency energy of the hihat would still open the gate. Filters have no effect on the frequency balance of the output signal. They only affect the key.
41. Comment on the use of an external key to improve the reliability of gating.
The external key make the threshold to be controlled from a signal other than the source signal. For example the bass drum signal can control a bass track to tighten up the rhythm section or let background vocals be controlled from one steady background track.
42. What is an expander?
An expander increases the dynamic range when the signal is below the threshold. In one way it’s the opposite to a compressor.
• When the signal is above the threshold level, there is no change.
• When the signal is below the threshold, the quieter the signal gets, the expander will make it even more so.
The expander has a ratio control like a compressor. 1:1 means no expansion; 20:1 means that the expander is working almost like a gate.
43. Why are compressors and gates often used together?
Compression always has the effect of increasing the noise level. Especially when make-up gain is used as discussed before. One way to get rid of the noise is to use a gate in combination so only signal of a certain levels is compressed. You can put the gate before or after the compressor. Different philosophies.
44. Comment on envelope shaping using a noise gate.
The noise gate is also capable of a variety of envelope shaping effects. One way is to put a more-or-less continuous signal through the gate, such as heavily distorted chords from an electric guitar, and then use the external key to chop it up into a rhythm and adjust the attack, hold and release controls to achieve the desired envelope.
Another useful gate effect is to compress the sound of an individual drum, especially if they have a little reverb, then gate it. The compressor can shape the envelope of the sound by emphasizing the attack or by allowing the reverb to increase in level as the drum dies away. The noise gate can then further process the envelope using the attack, hold and release controls.
45. Comment on gated reverb.
The gate is used to terminate the reverb decay causing an abrupt end to the reverb when the reverb goes under threshold. Popular in the 80sused a lot by Phil Collins.
Sources:
Rumsey, F. & McCormick, T. (2004). Sound and Recording: An Introduction, 4th ed. Oxford, Focal Press
http://www.soundonsound.com/sos/jan00/articles/mix.htm
http://www.soundonsound.com/sos/1994_articles/aug94/mixautomation.html
http://www.soundonsound.com/sos/1996_articles/apr96/compression.html
http://www.sfu.ca/sca/Manuals/ZAAPf/c/compressors.html
http://www.songstuff.com/articles.php?selected=44
http://www.soundonsound.com/sos/feb00/articles/mixauto.htm
http://www.soundonsound.com/sos/jan01/articles/advanced.asp |
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Sun Sep 25, 2005 1:46 pm |
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K
Joined: 12 Apr 2005
Posts: 10
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1. What is the function of mixing desk automation?
ANSWER: automatation is there so that if ajustments need to be made during the mix to the level of the faders . using automation the faders can all be ajusted at seperate times
2. Why might the faders have to be moved during the mix?
ANSWER: faders might have to be moved during the mix to fade in or out seperate tracks or to change the volume of specific instruments at specific times
3. What aspects of mixing would normally be automated on an analogue console?
ANSWER: the aspects of mixing that would normally be automated would be paning , volume and eq
4. Comment on VCA vs. Moving Fader automation.
ANSWER: VCA voltage controll amplifer is an audio function of a DC volvage . VCA controlls the level of audio signal of an external DC voltage in the console . equipt for automated mix down VCA's perform many fader/switch eq functions . Moving faders are controlled by an inside computer and they are all undated constitenly . data can be stored as vertial mix and everything can be instently recalled
5. Describe write/update/read.
ANSWER: with automation we have 3 things to do : write is to write the automated memory to the hard disk , update is adding or subtracting information from the automation , it updates automaticly. read is to read the stored information back , so it shows you your automation
6. How does an automated mix session start?
ANSWER: start the automation mix by setting everything at the level they should be at at the start of the song . ie . eg , volume , pan
7. How would a section of automation data be re-recorded?
ANSWER: go to the start of the song and reset everything to the correct levels and run through the song again
8. How are automation 'punch-ins' blended smoothly with existing data?
ANSWER: punch ins are blended smoothly with existing data by setting selected channels levels to the start levels and record from where the change should take place
9. How could a complex series of moves be increased in level by say 3dB?
ANSWER: set the faders and everything you wish to move to a group and turn up the group
10. Describe fader grouping.
ANSWER: fader grouping is assigning a number ot tracks for example a drum kit mix to a group which will contol the universal voulume level , pan and eq of the drum kit
11. How could EQ, for instance, be automated using an analogue mixing console?
ANSWER: EQ could be uutomated using VCE (voltage controlled equiliser) similar to VCA's
12. How would EQ be automated using a digital mixing console?
ANSWER: using a digital desk the automation would be programed in
13. What is 'recall'?
ANSWER: recall is like a storage system for mixed settings , so that at the touch of a button the mix will be changed back to the old settings assigned to that button
14. What advantages does a digital console have over an analogue console regarding recall?
ANSWER: a digital concole would have a lot more storage space that an analogue console regarding recall
15. Does a compressor act upon loud signals or quiet signals? What does it do to the signals upon which it acts?
ANSWER: a compressor acts upon both loud and quite signals . it reduces / increasess the level to a set threshhold making louder parts quiter and adding make up gain to quiter parts
18. What is the function of 'make up gain'?
ANSWER: make up gain gives an over all compressed track a boost
19. How is a compressor usually connected to a mixing console to compress a single signal?
ANSWER: a compressor is usly connected to a mixing console as in insert effect and is usly connected by aux send to one channel and then returned to the same channel
20. How is a compressor connected to a mixing console to compress the entire mix?
ANSWER: to compress the entire mix the compressor would be inserted into the over all sterio mix
21. Explain 'ratio', in the context of compression.
ANSWER: ths ratio is the signal decimal range between input and output ( such as 2:1 , 4:1 , 8:1)
22. Describe the difference between hard knee and soft knee.
ANSWER: hard knees and soft kness have got to do with the treshold in gating and compression . with a hard knee as soon as the volume reaches the treshold the volume will be compressed and brought down straight away . with a soft knee the voulme will get comreseed graduily rather than straight away like a hard knee
23. What are 'breathing' and 'pumping'?
ANSWER: if the relise time is set to short and full gain is restored each time the signal fell below the threshold it would add adbile side effects like breathing and pumping
24. What happens if the release time is too long?
ANSWER: if the release time is to long during a loud section of the song it will reduse the gain and if this is persistant through a quite section , it will make the quite section unadible
25. What does it mean if the gain reduction meter is showing frequent changes?
ANSWER: if the gain reduction meter is showing frequent changes it means that the track is quite high in volume and parts of it are being brought down in level
26. Describe the effect of compression on noise level.
ANSWER: compression on noise level can sometimes rase the noise level
27. Describe the function of the stereo link switch.
ANSWER: the funtion of the sterio link switch is so that the same thing happens to both sides of the signal .ie if the siganl was over the threshhold in one channel and not the other , using the sterio link swith , both sides will me compessed in the same way
28. What is the side chain input?
ANSWER: on a standerd compresser there are input and output jacks which are know as the side chain or the key input , so that an equiliser or an effect unit can be connected to the compresser
29. Describe a typical use of the side chain input.
ANSWER: the side chain input is comanly used to connect an equiliser to a compresser , so that .ie . to remove all low frequences from a signal , so when the siganl is fed back into the side chain input it tells the compresses to only allow through the hard trebile frequences . this is often used to get rid of sililane from a vocal track . the side chain is allso used in a way called ducking , which most djs use , the microphone input is fed into the input side chain so that when the dj specks the compresser processes the sound and the volume of the song goes down , when the dj stops talking the volume returns to normal
30. Is a noise gate usually effective on a mixed stereo signal?
ANSWER: a noise gate is sometimes effective on a mixed sterio signal , but just to get rid noise at the start and or end of a song . a noise gate would not be used on the actual overall song sterio mix , bacause it would take away from the over all sound , and would mess up the mixed sterio signal . the instuments should be gated seperatly before the song is mixed
31. Is a noise gate effective on a signal where the instrument plays all the time?
ANSWER: when it is set to the correct level it can be very effective , if its not set correctly it will do nothing or it will not do what you wish
32. Is a noise gate effective on a single noisy signal where there gaps in the playing?
ANSWER: yes it is very effective bacause you can set it to open and close on it on the siganl
33. Why is it often considered beneficial to gate some or all of the mics on a drum kit (except the overheads)?
ANSWER: it is often considered beneficial to gate some or all of the drum mics so that we can erradacate sounds of diffrent drums from the spicific channal therefore being able to create a better mix by only having one pure sound per channel .ie kick, snare
34. How many gates are often used in live sound: none, a few or many?
ANSWER: few gates would be offten used , depending on the band , venue and the drum kit used . sometimes none would be used used, sometimes lots would be used , it depends on the situation
35. How is the noise gate connected to the mixing console?
ANSWER: a noise gate is connected to the mixing console throught the insert socket on the desk . ie if you were using a rack unit with your noise gate built into it , you would plug the lead coming from the noise gate into the insert socket of the channel you wish to gate . the level of the gate will be controlled from your rack unit , the fader on the desk will control the volume of the gated channel
36. What is the function of the Threshold control?
ANSWER: a threshold can be changed as you wish to decide on the volume of the signal at which the gate will start taking effect
37. What is the function of the Range control?
ANSWER:range controll is what we use compressors for . some instuments are louder in one octive that another so you use range controll to keep everything at a certain level, the music does not get to loud or to soft
38. Comment on the Attack, Hold and Release (Decay) controls.
ANSWER: attack controlls how long it takes for the sound to get to its loudest point , hold determins how long it will stay at that level , and relise or decay controlls how long it takes for sound to come away from its loudest point into nothing
39. What would happen if a stereo signal was gated, but the stereo link function was not selected?
ANSWER: if the sterio link funrion was not enabiled each channel of the sterio mix would gate at diffrent times and diffrently , so this would not sound good
40. Why are side-chain filters beneficial?
ANSWER: side-chain filters are benefical because it allows an outside mic, instument , or synth to controll or trigger output of the gates main audio path . ie into to blondies heart of glass
41. Comment on the use of an external key to improve the reliability of gating.
ANSWER: an external key can be used to perfectly time gating to open and shut insynic with the messured tempo , causing the gate to open and shut on specfic beats
42. What is an expander?
ANSWER: an expander is signal progress in which dinamic range of a signal is increased
43. Why are compressors and gates often used together?
ANSWER: compressoers and gates are often used together because used as a team they get a solid level of sound on a perticular instrument and iranicate noise that can effect compressed signal
44. Comment on envelope shaping using a noise gate.
ANSWER:
45. Comment on gated reverb.
ANSWER: gated reverb is a reverb sound that cuts off when the reverb gets to a cetain level , it starts big then cuts off suddenly |
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Mon Sep 26, 2005 9:19 am |
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