1
Parallel compression, also known as New York compression, is a dynamic range compression
technique used in sound recording and mixing. Parallel compression, a form of upward compression, is
achieved by mixing an unprocessed 'dry', or lightly compressed signal with a heavily compressed version
of the same signal. Rather than bringing down the highest peaks for the purpose of dynamic range
reduction, it reduces the dynamic range by bringing up the softest sounds, adding audible detail. [1] It is
most often used on stereo percussion buses in recording and mixdown, on electric bass, and on vocals in
recording mixes and live concert mixes.[2]
Dynamic range compression
From Wikipedia
This article is about a process that intentionally reduces the dynamic range of audio signals. For similar
reductions caused by circuit imperfections, see Gain compression. For processes that reduce the size of
digital audio files, see Audio compression (data). For processes that reduce the size of data files in
general, see Data compression.
A rack of compressors in a recording studio
Dynamic range compression, also called DRC (often seen in DVD and car CD player settings) or simply
compression reduces the volume of loud sounds or amplifies quiet sounds by narrowing or
"compressing" an audio signal's dynamic range. Compression is commonly used in sound recording and
reproduction and broadcasting.[1]
The dedicated electronic hardware unit or audio software used to apply compression is called a
compressor. Compressors often have attack and release controls that vary the rate at which
compression is applied and smooth the effect.
Contents
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1 Types
2 Design
3 Compressor controls and features
o 3.1 Threshold
o 3.2 Ratio
o 3.3 Attack and release
o 3.4 Soft and hard knees
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o 3.5 Peak vs RMS sensing
o 3.6 Stereo Linking
o 3.7 Makeup gain
o 3.8 Look-ahead
4 Use
5 Limiting
6 Side-chaining
7 Parallel compression
8 Multiband compression
9 Serial compression
10 Common uses
o 10.1 Public spaces
o 10.2 Music production
o 10.3 Voice
o 10.4 Broadcasting
o 10.5 Rock stations
o 10.6 Marketing
11 Other uses
12 Compressors for software audio players
13 See also
14 References
15 External links
Types
Two main methods of dynamic range reduction
Downward compression
Upward compression
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Downward compression reduces loud sounds over a certain threshold while quiet sounds remain
unaffected. Upward compression increases the loudness of sounds below a threshold while leaving
louder passages unchanged. Both downward and upward compression reduce the dynamic range of an
audio signal.[2]
An expander performs the opposite function, increasing the dynamic range of the audio signal.[3]
Expanders are generally used to make quiet sounds even quieter by reducing the level of an audio signal
that falls below a set threshold level. A noise gate is a type of expander.[2]
Design
A feed-forward compressor design (left) and feedback design (right)
The signal entering a compressor is split, one copy sent to a variable-gain amplifier and the other to a
side-chain where a circuit controlled by the signal level applies the required gain to an amplifier stage.
This design, known as a "feed-forward" type, is used today in most compressors. Earlier designs were
based on a "feedback" layout where the signal feeding the control circuit was taken after the amplifier.
There are a number of technologies used for variable gain amplification, each having different
advantages and disadvantages. Vacuum tubes are used in a configuration called 'variable-mu': the gridto-cathode voltage changes to alter the gain.[4] Also used is a voltage controlled amplifier (VCA), which
has its gain reduced as the power of the input signal increases. Optical compressors use a light sensitive
resistor (LDR) and a small lamp (LED or electroluminescent panel[5]) to create changes in signal gain.
This technique is believed by some to add smoother characteristics to the signal because the response
times of the light and the resistor soften the attack and release. Other technologies used include field
effect transistors and a diode bridge.[6]
When working with digital audio, digital signal processing techniques are commonly used to implement
compression via digital audio editors, or dedicated workstations. Often the algorithms used emulate the
above analog technologies.
Compressor controls and features
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Different compression ratios
Threshold
A compressor reduces the level of an audio signal if its amplitude exceeds a certain threshold. It is
commonly set in dB, where a lower threshold (e.g. -60 dB) means a larger portion of the signal will be
treated (compared to a higher threshold of −5 dB).
Ratio
The amount of gain reduction is determined by ratio: a ratio of 4:1 means that if input level is 4 dB over
the threshold, the output signal level will be 1 dB over the threshold. The gain (level) has been reduced by
3 dB:
Threshold = −10 dB
Input = −6 dB (4 dB above the threshold)
Output = −9 dB (1 dB above the threshold)
The highest ratio of ∞:1 is often known as 'limiting'. It is commonly achieved using a ratio of 60:1, and
effectively denotes that any signal above the threshold will be brought down to the threshold level (except
briefly after a sudden increase in input loudness, known as an "attack").
Attack and release
The attack and release phases in a compressor
A compressor might provide a degree of control over how quickly it acts. The 'attack phase' is the period
when the compressor is decreasing gain to reach the level that is determined by the ratio. The 'release
phase' is the period when the compressor is increasing gain to the level determined by the ratio, or, to
zero dB, once the level has fallen below the threshold. The length of each period is determined by the
rate of change and the required change in gain. For more intuitive operation, a compressor's attack and
release controls are labeled as a unit of time (often milliseconds). This is the amount of time it will take for
the gain to change a set amount of dB, decided by the manufacturer, very often 10 dB. For example, if
the compressor's time constants are referenced to 10 dB, and the attack time is set to 1 ms, it will take 1
ms for the gain to decrease by 10 dB, and 2 ms to decrease by 20 dB. [7]
In many compressors the attack and release times are adjustable by the user. Some compressors,
however, have the attack and release times determined by the circuit design and these cannot be
adjusted by the user. Sometimes the attack and release times are 'automatic' or 'program dependent',
meaning that the times change depending on the input signal. Because the loudness pattern of the
source material is modified by the compressor it may change the character of the signal in subtle to quite
noticeable ways depending on the settings used.
Soft and hard knees
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Hard Knee and Soft Knee compression
Another control a compressor might offer is hard/soft knee. This controls whether the bend in the
response curve is a sharp angle or has a rounded edge. A soft knee slowly increases the compression
ratio as the level increases and eventually reaches the compression ratio set by the user. A soft knee
reduces the audible change from uncompressed to compressed, especially for higher ratios where the
changeover is more noticeable.[8]
Peak vs RMS sensing
A peak sensing compressor responds to the instantaneous level of the input signal. While providing
tighter peak control, peak sensing might yield very quick changes in gain reduction, more evident
compression or sometimes even distortion. Some compressors will apply an averaging function
(commonly RMS) on the input signal before its level is compared to the threshold. This allows a more
relaxed compression that also more closely relates to our perception of loudness.
Stereo Linking
A compressor in stereo linking mode applies the same amount of gain reduction to both the left and right
channels. This is done to prevent image shifting that can occur if both channels are compressed
individually. It becomes noticeable when a loud element that is panned to either edge of the stereo field
raises the level of the program to the compressor's threshold, causing its image to shift toward the center
of the stereo field.
Stereo linking can be achieved in two ways: Either the compressor sums to mono the left and right
channel at the input, then only the left channel controls are functional; or, the compressor still calculates
the required amount of gain reduction independently for each channel and then apply the highest amount
of gain reduction to both (in such case it could still make sense to dial different setting on left and right
channels as one might wish to have less compression for left-side events[9]).
Makeup gain
Because the compressor is reducing the gain (or level) of the signal, the ability to add a fixed amount of
make-up gain at the output is usually provided so that an optimum level can be used.
Look-ahead
The look-ahead function is designed to overcome the problem of being forced to compromise between
slow attack rates that produce smooth-sounding gain changes, and fast attack rates capable of catching
transients. Look-ahead is a misnomer in that the future is not actually observed. Instead, the input signal
is split, and one side is delayed. The non-delayed signal is used to drive the compression of the delayed
signal, which then appears at the output. This way a smooth-sounding slower attack rate can be used to
catch transients. The cost of this solution is that the signal is delayed.
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Use
An audio engineer might use a compressor to reduce the dynamic range of source material in order to
allow it to be recorded optimally on a medium with a more limited dynamic range than the source signal or
else in order to change the character of an instrument being processed.
Engineers wishing to achieve dynamic range reduction with few obvious effects might choose a relatively
low threshold and low compression ratio so that the source material is being compressed very slightly
most of the time. To deliberately soften the attack of a snare drum, they might choose a fast attack time
and a moderately fast release time combined with a higher threshold. To accentuate the attack of the
snare, they might choose a slower attack time to avoid affecting the initial transient. It is easier to apply
these controls with a basic knowledge of acoustics.
Limiting
Limiting and clipping compared. Note that clipping introduces a large amount of distortion whereas
limiting only introduces a small amount while keeping the signal within the threshold.
Main article: Limiting
Compression and limiting are not different in process but in degree and perceived effect. A limiter is a
compressor with a high ratio and, generally, a fast attack time. Most engineers consider compression with
ratio of 10:1 or more as limiting.[10] Engineers sometimes refer to soft and hard limiting which are
differences of degree. The "harder" a limiter, the higher its ratio and the faster its attack and release
times.
Brick wall limiting has a very high ratio and a very fast attack time. Ideally, this ensures that an audio
signal never exceeds the amplitude of the threshold. Ratios of 20:1 all the way up to ∞:1 are considered
to be 'brick wall'.[10] The sonic results of more than momentary and infrequent hard/brick-wall limiting are
harsh and unpleasant, thus it is more common as a safety device in live sound and broadcast
applications.
Some modern consumer electronics devices incorporate limiters. Sony uses the Automatic Volume
Limiter System (AVLS), on some audio products and the PlayStation Portable.
See also: Clipping (audio)
Side-chaining
7
The sidechain of a feed-forward compressor
When side-chaining, the compressor uses the volume level of an input signal to determine how strongly
the compressor will reduce the gain on its output signal. This is used by disc jockeys for ducking –
lowering the music volume automatically when speaking. The DJ's microphone signal is routed to the
compressor's sidechain so that whenever the DJ speaks the compressor reduces the volume of the
music. A sidechain with equalization controls can be used to reduce the volume of signals that have a
strong spectral content within a certain frequency range: it can act as a de-esser, reducing the level of
vocal sibilance in the range of 6–9 kHz. A de-esser helps reduce high frequencies that tend to overdrive
preemphasized media (such as phonograph records and FM radio). Another use of the side-chain in
music production serves to maintain a loud bass track without the bass drum causing undue peaks that
result in loss of overall headroom.
A linked stereo compressor without a sidechain input can be used as a mono compressor with a
sidechain input. The "key", "trigger" or sidechain signal is sent to the left input of the stereo compressor
while the signal that is to be compressed is routed through the right channel.
This technique is not to be confused with Parallel compression, which was referred to as "side chain"
compression in a 1977 Studio Sound article by Mike Bevelle.
Parallel compression
One technique is to insert the compressor in a parallel signal path. This is known as parallel compression
and can give a measure of dynamic control without significant audible side effects, if the ratio is relatively
low and the compressor's sound is relatively neutral. On the other hand, a high compression ratio with
significant audible artifacts can be chosen in one of the two parallel signal paths—this is used by some
concert mixers and recording engineers as an artistic effect called New York compression or Motown
compression. Combining a linear signal with a compressor and then reducing the output gain of the
compression chain results in low-level detail enhancement without any peak reduction (since the
compressor will significantly add to the combined gain at low levels only). This will often be beneficial
when compressing transient content, since high-level dynamic liveliness is still maintained, despite the
overall dynamic range reduction. Unlike normal limiting and downward compression, fast transients in
music are retained in parallel compression, preserving the "feel" and immediacy of a live performance.
Because the method is less audible to the human ear, the compressor can be set aggressively, with high
ratios for strong effect
Multiband compression
Multiband (also spelled multi-band) compressors can act differently on different frequency bands. The
advantage of multiband compression over full-bandwidth (full-band, or single-band) compression is that
unneeded audible gain changes or "pumping" in other frequency bands is not caused by changing signal
levels in a single frequency band.
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Multiband compressors work by first splitting the signal through some number of bandpass filters or
crossover filters. The frequency ranges or crossover frequencies may be adjustable. Each split signal
then passes through its own compressor and is independently adjustable for threshold, ratio, attack, and
release. The signals are then recombined and an additional limiting circuit may be employed to ensure
that the combined effects do not create unwanted peak levels.
Software plug-ins or DSP emulations of multiband compressors can be complex, with many bands, and
require corresponding computing power.
Multiband compressors are primarily an audio mastering tool, but their inclusion in digital audio
workstation plug-in sets is increasing their use among mix engineers. Hardware multiband compressors
are also commonly used in the on-air signal chain of a radio station, either AM or FM, in order to increase
the station's apparent loudness without fear of overmodulation. Having a louder sound is often considered
an advantage in commercial competition. However, adjusting a multiband output compressor of a radio
station also requires some artistic sense of style, plenty of time and a good pair of ears. This is because
the constantly changing spectral balance between audio bands may have an equalizing effect on the
output, by dynamically modifying the on-air frequency response. A further development of this approach
is programmable radio output processing, where the parameters of the multiband compressor
automatically change between different settings according to the current programme block style or the
time of day.
Serial compression
Serial compression is a technique used in sound recording and mixing. Serial compression is achieved by
using two fairly different compressors in a signal chain. One compressor will generally stabilize the
dynamic range while the other will more aggressively compress stronger peaks. This is the normal
internal signal routing in common combination devices marketed as "compressor-limiters", where an RMS
compressor (for general gain control) would be directly followed by a fast peak sensing limiter (for
overload protection). Done properly, even heavy serial compression can sound very natural in a way not
possible with a single compressor. It is most often used to even out erratic vocals and guitars.
Common uses
Public spaces
Compression is often used to make music sound louder without increasing its peak amplitude. By
compressing the peak (or loudest) signals, it becomes possible to increase the overall gain (or volume) of
a signal without exceeding the dynamic limits of a reproduction device or medium. The net effect, when
compression is applied along with a gain boost, is that relatively quiet sounds become louder, while
louder sounds remain unchanged.
Compression is often applied in this manner in audio systems for restaurants, retail, and similar public
environments, where background music is played at a relatively low volume and needs to be compressed
not just to keep the volume fairly constant, but also in order for relatively quiet parts of the music to be
audible over ambient noise, or audible at all.
Compression can be used to increase the average output gain of a power amplifier by 50 to 100% with a
reduced dynamic range. For paging and evacuation systems, this adds clarity under noisy circumstances
and saves on the number of amplifiers required.
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Music production
Compression is often used in music production to make performances more consistent in dynamic range
so that they "sit" in the mix of other instruments better and maintain consistent attention from the listener.
Vocal performances in rock music or pop music are usually compressed in order to make them stand out
from the surrounding instruments and to add to the clarity of the vocal performance.
Compression can also be used on instrument sounds to create effects not primarily focused on boosting
loudness. For instance, drum and cymbal sounds tend to decay quickly, but a compressor can make the
sound appear to have a more sustained tail. Guitar sounds are often compressed in order to obtain a
fuller, more sustained sound.
In electronic dance music, side-chaining is often used on basslines, controlled by the kick drum or a
similar percussive trigger, to prevent the two conflicting, and provide a pulsating, rhythmic dynamic to the
sound.
Most devices capable of compressing audio dynamics can also be used to reduce the volume of one
audio source when another audio source reaches a certain level; see side-chaining above.
Compression is an indispensable tool for controlling audio signal levels, whether you are a studio
engineer, videographer, field-recording tech, home enthusiast, or performing musician. Since the advent
of audio-tape recording, there has been a never-ending quest to maintain constant signal levels to
achieve optimal audio performance. Let's take a closer look at compression and how you can make it
work for you.
What is it?
A compressor/limiter is designed to attenuate an audio signal as it approaches a predetermined threshold
level. Some vintage units like the Teletronix LA-2A or the newer DBX 160AD feature few knobs, but are
quick, easy to use, and have a unique sonic signature born of their excellent designs. Others, such as the
Avalon VT-747SP or Focusrite Compounder, offer many control options for extreme versatility.
There are two main functions that a compressor/limiter can fulfill.
1) Managing signal levels
A compressor monitors the level of your audio signals much the same way an audio engineer maintains
consistent recording levels while capturing a live performance. The piano, for example, is an instrument
capable of delivering an extremely wide dynamic range, from very quiet passages to thundering
crescendos. As the pianist plays louder, it is the engineer's job to decrease the signal level to prevent the
recording equipment from overloading. Conversely, when the pianist returns to a more modest volume,
the engineer must increase the signal to its earlier level to maintain a consistent recording level.
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But adjusting your input level manually for the duration of such a recording would take a fair amount of
skill, and an almost inhumanly quick hand, to catch every unexpected loud volume peak as it occurs.
A compressor can make your life a great deal easier by making these gain changes for you—by
decreasing your audio signal level during loud passages, quickly and accurately.
Applying compression to an audio signal can help keep these stronger dynamics under control with
minimal sonic alteration of the original signal. Unlike adding reverb or delay to sweeten your recording, a
compressor, properly set, is almost inaudible while doing its job. In fact, if all you are trying to do is control
your amplitude levels, then the more transparent the process, the better for your recording.
2) As an effect
By using stronger settings, it is also possible to use compression as an audible effect. This can add
punch and personality to your recordings. As mentioned previously, a large number of audio sound
sources have a dynamic range that can exceed the limits of many recording devices.
Compressors take signals with a very wide dynamic range and compress them into a narrower dynamic
range to help you attain a better match between your sound source and audio recording chain. Heavy
compression squeezes the same amount of input signal through a tighter aperture, which can have
several results:
A) More perceived source signal level at lower volumes
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B) Increase in sustain of some instruments, especially guitar, piano, and bass
C) Strong, smooth, dynamically consistent tone that exhibits a certain sonic "weight," like a radio
announcer's voice
D) More reactive settings can produce maximum punch on instruments like drums, bass, and guitar
Strong compressor settings, which can be heard every day in the broadcast world, are clearly audible and
have a unique flavor. The thick, rich voice of a radio announcer is not only dependent upon the quality of
the source voice, but also on equalization and heavy doses of compression. If you have ever watched
programming on television and have been jolted by the higher volume of the interstitial commercial, then
you have experienced the effects of compression. By cramming as much signal as possible into a
narrower dynamic space, announcers, commercials, and musical material are guaranteed to have a
strong sonic footprint when vying against competing neighboring stations.
Making the Connection
Even though the compressor can be used as an effect, it is important to remember that 100% of your
audio signal must pass through it in order for it to do its job effectively. A delay or reverb unit is usually
connected to the effects send of a mixer, which then allows you to adjust its desired percentage. A
compressor should be placed directly in line with the signal so that you are controlling its percentage from
the unit itself.
This can be done by connecting directly to the unit or, better still, by making use of the insert connections
on your mixer. An insert jack gives you an access point to the signal after it has been properly
preamplified at the mixer's input, but before it is sent through the EQ, effects, and other sections of the
mixer for other modification. Insert cables are Y-cables that feature a single stereo (tip-ring-sleeve) plug
on one end and two mono (tip-sleeve) plugs at the ends of the Y. The single stereo plug connects to the
insert jack of your mixer, while the Y ends connect to the input and output of your compressor. The jack
and cable are wired in such a way as to send the signal from the mixer to the compressor on one side of
the cable, and from the compressor back to the mixer, with one simple connection. The sound can then
continue down the channel strip through the EQ, effects, fader, and other controls.
As with anything, there are exceptions to this rule that dictate other specialized uses. You may wish to
manually split the source signal into several different frequency bands and compress only the lows, for
example, to introduce a form of multi-band compression. (More on this later.)
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Controls and Concepts
The key to using a compressor/limiter properly is in learning what each control does on its own, and also
understanding how they react with one another. Higher ratio settings may compel you to add more output,
for example. Let's have a look.
Threshold: This control lets you choose the decibel level at which the unit will begin attenuating your
signal. Lower settings will cause the unit to work on even the quietest signals, while higher settings let
louder signals pass unmodified until the selected threshold is reached.
Ratio: The ratio control dictates how much compression you are applying to the signal and it is marked in
decibels with settings such as 1:1, 2:1, 4:1, etc. A setting of 1:1 represents no applied compression. A
setting of 2:1, for example, means that for every 2dB the signal goes above the chosen threshold, only
1dB will be allowed to pass.
You may also notice a small infinity symbol at the far end of this range, denoting a maximum compression
setting or limiting.
There are times when you may simply want to create a ceiling for your audio levels without affecting them
otherwise. Limiting may be thought of as compression with an infinitely-high ratio, meaning that any signal
that approaches the chosen threshold can never go past it. This is great for preventing overload peaks on
your main mix, or for attenuating a handful of louder notes that may otherwise overload your recording
device.
Attack: The attack time is the speed at which compression will kick in after the signal crosses the chosen
threshold. Lower settings or faster times will create a snappier response, while higher or longer settings
will give a more relaxed feel. Instruments with a very quick attack, like drums and bass, usually have a lot
of energy right at the start of their sound. A fast attack will catch these transients and help keep your
signal within safe levels.
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Release: The release time controls the time that the compressor will continue to work after the signal
drops below the chosen threshold. Shorter settings will release the signal immediately, while longer
settings hang on to it, creating an effect of increased sustain, especially for guitars, as mentioned earlier.
Pumping/Breathing: Different instruments have varied amplitude envelopes. Some, like drums, are short
and fast while others have a more gentle attack with more sustain, such as a violin or human voice. By
setting the attack and release times to reflect the nature of the program material, you will be able to
achieve smooth, transparent results. If inaccurate settings are used on shorter, sharp sounds like drums,
higher compression settings will produce an audible pumping or breathing effect as the compressor tries
to catch each individual drum hit or bass note unsuccessfully. This is usually considered undesirable, but
can be used constructively and fine-tuned as an effect to alter the envelope of drums and other
instruments.
Output or "Makeup" Gain: This control allows you to bring your total signal output back up to a more
useable level if it has been decreased by higher compression settings. As you lower the threshold and
increase the compression ratio, your total signal output will, no doubt, decrease. The output knob will let
you tailor your final output to agree more with your requirements and sensibilities.
Limiter: A separate limiter section will usually override any other settings and provide a straightforward
preset peak reduction structure.
Expander/Gate: Many compression units include an Expander/Gate circuit to increase their versatility. An
expander has the opposite function of a compressor— it expands the dynamic range of your signal,
making softer sections seem quieter and louder moments even more so. Most modern units feature
"downward expansion" to offer you a form gain reduction that brings low-level signals even lower. An
extreme setting of expansion called "gating" allows the incoming signal to pass only if it reaches a certain
level, as set by the threshold control. The release time will dictate the time envelope of the "gate." This
setting can be used to reduce noise by lowering the signal to 0dB when the noise floor is reached, or it
can be used as an effect that abruptly opens to let the signal pass and then closes to dead silence after it
passes the threshold (think in terms of Phil Collins' drums on the song "In the Air Tonight").
OverEasy/Hard and Soft Knee: The attack dictates how the compressor will behave when the signal
reaches the threshold. A hard knee setting (normal) represents a sudden application of compression right
at the onset of the threshold, and is ideal for strong compression effects. A soft knee or OverEasy setting
will produce a smoother transition to the onset of compression, which can be great for an easier feel and
more latitude.
Give it a try
At first it may be a bit difficult to get the results that you want from your compressor. All of the controls are
so interactive that it will take some trial and error to get the hang of it. Below are some starting points for a
few popular sources, but you must remember that these are not hard and fast settings, since every input
source will be different.
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What else can it do?
On the rear panel of some compressors you may find an input labeled "side-chain" which is a direct
connection to the unit's detection circuitry. What useful things can you do with this input?
Ducking: The technique of reducing the level of one signal with the increased output level of another is
called "ducking," and it is used widely in broadcast and voice-over applications. Let's suppose that a radio
station is running its music through a compressor, and that the DJ's microphone is connected to the sidechain of the compressor. When the DJ speaks, the level of the music will automatically be reduced so that
he can make his announcements. When he stops speaking, the compressor will return the music to its
normal level.
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De-essing: By pairing a compressor with an equalizer you can reduce the sibilance, or overly-accentuated
vocal s, sh, ch, z, and j sounds in your source material. Sibilance occurs in a frequency range of
anywhere from 4 to 8 kHz, and can be difficult to attack with EQ alone. By feeding a 4-8 kHz boosted
copy of the vocals into the side-chain input of the compressor, you will cause it to respond when these
offending frequencies are detected.
Multi-Band Compression: There are times when it would be a wiser choice to compress only a certain
range of the frequency spectrum, and the tool for this job is the multi-band compressor. If you were to run
an entire song mix through a compressor you would notice that because low frequency energy is
inherently much stronger than high frequency energy, it would react to the thump of the bass drum, bass
guitar, and any other bass-heavy source. If you wanted to compress the low end separately to give it a
tighter feel but leave the highs free to breathe, then a multi-band unit will let you adjust your compression
levels for several frequency ranges simultaneously.
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Plug-ins
Software compressor/limiters are a convenient and cost-effective way to maintain your computer tracks.
There is an incredible range available that covers everything from vintage recreations to powerful
mastering suites. They will open directly in your audio application without the need for external patching.
In most cases, by purchasing one you will be able to open multiple instances to apply to several tracks at
once.
Why has compression become even more important today?
Analog tape systems have provided us with a huge number of not only classic but historical recordings, in
all styles and forms. One reason for the incredibly warm and rich sound that is associated with magnetic
tape is the elasticity of the recording chain. Almost every bit of vintage analog gear, from the microphone
and preamps to the console and tape machine, absorbed strong signals by saturating (distorting) in a
very pleasant way. As vacuum tube and tape technology is driven slightly over its working limits with high
input levels, for example, the resulting harmonic distortion can add a certain sort of "fatness" to the
original sound source.
Digital audio recording requires a different set of guidelines to attain optimal results. Unlike analog
recording, the digital recording chain is not as tolerant of any audio signals that may exceed the
recommended input level of the equipment. This includes digital video cameras, CD and DVD recorders,
stand-alone hard disk recorders, computer audio workstations, or any unit that is based on 1's and 0's.
The more information you feed into a digital recorder, the more information it has to work with, and the
lower the noise level. Unfortunately, any peaking input signals will create a noticeable form digital
distortion that is generally neither pleasant nor desired.
Side-chain pumping is a more advanced technique using a compressors 'side-chain' feature which,
"uses the amplitude envelope (dynamics profile) of one track as a trigger for a compressor used in
another track."[4] When the amplitude of a note of the side-chained instrument surpasses the threshold
setting of the compressor it attenuates the compressed instrument, producing volume swells offset from
the side-chained note by a selected release time.[4] Found in house, techno, IDM, hip hop, dubstep, and
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drum 'n' bass, Eric Prydz's "Call On Me" is credited with popularizing the technique, though Daft Punk's
"One More Time" contributed, while clear examples include Madonna's "Get Together" and Benny
Benassi's "My Body (feat. Mia J.)"[5]
One more Time: Every beat of the kick drum pulls the rest of the mix down, causing the whole track to pump
rhythmically around the kick.