One Channel on Art Comp Is Louder Than the Other

Sound signals take very wide height-to-average signal-level ratios, sometimes referred to as dynamic range, which is the difference between the loudest level and the softest level. This can create issues in both alive and recording environments when gain staging a signal because when enough proceeds is applied to capture the softest level adequately, a peak signal tin cause overload in the audio chain, resulting in bespeak baloney. Dynamics processing is the procedure of altering the dynamic range of an audio source to make it easier to identify in the overall mix. Mutual types of dynamics processors include:

Compressor. A compressor is a type of amplifier in which gain is dependent on the bespeak level passing through it. You can prepare the maximum level a compressor allows to pass through, thereby causing automatic gain reduction above some predetermined signal level, besides known as the "threshold." Punch, credible loudness, and presence are just three of the many terms used to describe the furnishings of compression.
Limiters. Similar to a compressor, a limiter is an amplifier that limits the upper dynamic range of a betoken to a specific threshold. Unlike a compressor, which works gradually to reduce the indicate, the limiter prevents almost any increase in gain at the upper end of the dynamic range.
Expanders. Expanders increase the dynamic range of a signal later the signal crosses a threshold. There are ii basic types of expansion: dynamic and downward.
Racket Gates. A noise gate helps to reduce unwanted sounds by only allowing the bespeak to be heard once information technology has exceeded a certain amplitude.

PreSonus has put together this brief tutorial to respond both commonly asked questions and explain dynamics terminology

The Problem with Dynamic Range

Dynamic range tin exist defined as the ratio betwixt the loudest possible audio level and the lowest possible level. For example, if a processor states that the maximum input level before distortion is +24 dBu, and the output noise floor is -92 dBu, then the processor has a total dynamic range of 116 dB (24 + 92 = 116 dB).

Some styles of music are much more dynamic than others. For example, the average dynamic range of an orchestral performance can range from -50 dBu to +x dBu, on average. This equates to a 60 dB dynamic range. Although 60 dB may non appear to be a large dynamic range, do the math, and you lot'll discover that +x dBu is 1,000 times louder than -50 dBu!

Rock music, on the other mitt, has a much smaller dynamic range: typically -10 dBu to +10 dBu, or xx dB. This makes mixing the various signals of a stone performance a much more tedious task because the level differences between the instruments are much more than subtle, and so simply using faders to balance the mix isn't going to solve the problem solitary.

Compression

Compressors are commonly used for many audio applications and role past lowering the uppermost dynamic range of a point at a gear up threshold. In one case the signal exceeds that threshold, the compressor volition engage and reduce it, by a set amount. Compressors also allow the engineer to decide how fast the gain reduction will engage and how slow it volition release.

Pinch reduces the amount by which a signal's output level can increase relative to the input level. It is useful for lowering the dynamic range of an musical instrument or song, making information technology easier to avoid distorting the output. Information technology likewise assists in the mixing procedure past reducing the amount of level changes needed for a particular instrument.

How severely the compressor reduces the signal, is adamant by ii parameters: ratio and threshold. A ratio of 2:ane or less is considered mild compression, reducing the output by a gene of two for signals that exceed the compression threshold. Ratios above 10:1 are considered hard limiting. Assuming a nominal input-betoken level, as the pinch threshold is lowered, more than of the input point is compressed.

So, how does compression help?

Permit's take the instance of a vocal performance, which normally has a wide dynamic range. Transients every bit usually the loudest portions of any instrument, but these tin exist far outside the boilerplate level of the song bespeak. This means that the level changes continuously and dramatically. This problem is compounded by many vocalists, who move around in front end of the microphone while performing, making the output level vary up and down unnaturally.

I solution to this trouble is known every bit "riding the fader." As its name indicates, this ways that the audio engineer constantly keeps their finger on the aqueduct fader, monitoring the level to ensure that it is never as well quiet or also loud. While this solution may work if you have a very circumspect sound engineer who's concerned with just i or two channels, it is non a good solution in a circuitous mix. This is where a compressor comes into the mix.

A compressor automatically controls gain without altering the subtleties of the performance, correcting this trouble by reducing the louder passages enough to be compatible with the overall operation.

Let's say that yous are mixing a rock performance with an boilerplate dynamic range of 20 dB (-10 dBu to +ten dBu). Yous wish to add together an uncompressed vocal to the mix. The average dynamic range of an uncompressed vocal is around 40 dB, ranging from as soft as -30 dBu upward to as loud as +x dBu. The passages that are +0 dBu and higher will be heard over the mix pretty clearly. Even so, the passages that are at -20 dBu and below volition never be heard over the roar of the residue of the mix. A compressor can be used in this situation to reduce (shrink) the dynamic range of the vocal so that it is approximately 10 dB (from 0 dBu to +10 dBu). At this dynamic range, the quieter aspects of the functioning are still well above the lower level of the mix, and louder phrases volition non overpower the mix, allowing the vocal to "sit in the track."

The same points can be made almost whatever instrument in the mix. Each musical instrument has its place, and a skillful compressor tin assist the engineer in creating the overall blend. For example, a kick pulsate can get lost in a wall of electric guitars. No matter how much the level is increased, the boot drum stays lost in the "mud." A touch of compression can tighten up that kick-drum sound, allowing it to dial through without cranking the level way up. A solo guitar can seem to be masked by the rhythm guitars. Compression tin can make your pb soar to a higher place the track without shoving the fader through the roof. Bass guitar can exist difficult to record. A consistent level with good attack can be achieved with proper compression, giving the bass the punch it needs to drive the lesser of the mix.

Because of this, most instruments need some form of compression, oft very subtle, to be properly heard in a mix. Of course, if an musical instrument sits perfectly in a mix without compression, then don't mess with it. But most of the fourth dimension you lot'll need it.

Overcompression: When Also Much is Just Too Much

A well-designed and properly adapted compressor should not be audible —unless, of course, it is done intentionally for issue, but that's some other article.

As well much compression can destroy the acoustic dynamic response of a performance. Furthermore, some people utilize a lot of compression to brand their mix equally loud as possible, emulating what they hear on the radio, only the top professionals ordinarily get that effect by careful compression during mastering, not during tracking and mixing.

If you apply a lot of compression in your tracks and mix, you might reduce the dynamic range to the bespeak that you haven't left the mastering engineer enough flexibility. So use compression often just don't become over the summit unless yous are doing it as an upshot. You lot notwithstanding want your mix to "breathe." If it feels similar it ramps upwards to one level and stays in that location without moving, yous've probably squashed your signals too much.

Sidechaining the Compressor

Sidechaining a compressor allows you lot to reduce the level of ane input source to make room for another. This is especially useful in alive circulate or applications where music and commentary are happening simultaneously. In recording applications, this is mostly accomplished with careful level automation. Compressor sidechaining allows y'all to achieve a similar event without having to ride the faders. Because of this, both StudioLive® Series 3 mixers and Studio One® provide sidechaining.

Below are ii of the most common uses:

Dialogue Ducking. This is probably the nigh well-known compressor sidechaining application. Consider a common House-of-Worship state of affairs where the pastor is leading a meditation while the piano or pre-recorded music is beingness played. Use a compressor on the stereo music track with a fairly low threshold, high ratio, a fast attack and a long release time, using the pastor'southward microphone channel equally the key source for the compressor. Now the compressor will react to level fluctuations from the pastor'due south microphone, allowing the music to naturally rise and fall in counterpoint to the speech design.
Bringing Out the Boot Drum. In some instances, a synth bass line, or a decorated bass guitar part interferes with the boot drum presence and punch in the mix. For this application, you volition employ a compressor to the bass channel, using the kick drum channel equally the key source, allowing your kick pulsate to dial through the bass line.

Compressor Components

Attack. Sets the speed at which the compressor acts on the input signal. A ho-hum assault time allows the beginning component of a signal (usually referred to as the initial transient) to pass through, uncompressed, whereas a fast set on time triggers compression immediately when a bespeak exceeds the threshold.
Automobile fashion. Fixes the attack and release times to a preprogrammed curve. Every StudioLive digital mixer offers this characteristic, helping to simplify compression for novice and exasperated professional users akin.
Pinch ratio. The ratio sets the compression slope, which is a function of the output level versus the input level. For example, if you lot have the ratio gear up to ii:one, any signal levels higher up the threshold setting will exist compressed at a ratio of 2:1. This means that for every 2 dB of level increase above the threshold, the compressor's output will only increase 1 dB.
Hard/soft knee joint. With hard-knee compression, the proceeds reduction applied to the signal occurs equally presently as the signal exceeds the level gear up past the threshold. With soft-articulatio genus compression, the onset of gain reduction occurs gradually afterwards the betoken has exceeded the threshold, producing a more musical response (to some folks).
Look-alee compression. Some digital compressors tin analyze what it is about to process ("await ahead") and tin place the set on time right at the onset of—or fifty-fifty before—the sound, resulting in null attack time. This is great for catching unwanted transients, but it must be used with care so as non to remove desirable transients, such every bit the attack of a snare drum. Considering of the amount of processing power necessary for this analysis, wait-alee compressors are virtually commonly found as plug-ins such as the PreSonus Channel Strip, Compressor, Multiband Dynamics, and Tricomp plug-ins for Studio One.
Brand-up Gain. When compressing a point, gain reduction unremarkably results in an overall attenuation of level. The proceeds control allows you to restore this loss in level and readjust the book to the precompression level (if desired).
Release. Sets the length of time the compressor takes to render the gain reduction back to zero (no gain reduction) after crossing below the compression threshold. Very short release times can produce a choppy or "jittery" sound, especially when compressing instruments that accept a lot of depression-frequency components, such every bit a bass guitar. Very long release times can upshot in an overcompressed, or "squashed," audio. All ranges of release can be useful, withal, and you lot should experiment to become familiar with different sonic possibilities
Threshold. When the bespeak's amplitude (level) exceeds the threshold setting, the compressor engages. Equally the threshold is lowered, compression begins at a lower aamplitude (book) and further limits the dynamic range of the signal.

Compression Settings: Starting Points

The following are the pinch presets that were used in the pop just discontinued PreSonus BlueMax. We have included them every bit a jumping-off betoken to go you started.

Vocals

Soft. This is an like shooting fish in a barrel compression with a low ratio setting for ballads, assuasive a wider dynamic range. It's skilful for alive apply. This setting helps the vocal "sit in the rail."

Threshold	Ratio	Attack	Release
-8.2 dB	one.8:1	0.002 ms	38 ms

Medium. This setting has more limiting than the Soft compression setting, producing a narrower dynamic range. It moves the song more up front in the mix.

Threshold	Ratio	Attack	Release
-3.three dB	2.eight:1	0.002 ms	38 ms

Screamer. This setting is for loud vocals. Information technology is a fairly difficult compression setting for a vocalist who is on and off the microphone a lot. It puts the voice "in your face up."

Threshold	Ratio	Attack	Release
-1.1 dB	3.8:1	0.002 ms	38 ms

Percussion

Snare/Kick. This setting allows the starting time transient through and compresses the residue of the point, giving a difficult "snap" up front and a longer release.

Threshold	Ratio	Attack	Release
-ii.one dB	3.5:1	78 ms	300 ms

Left/Right (Stereo) Overheads. The low ratio and threshold in this setting gives a "fat" profile to even out the sound from overhead drum mics. Depression end is increased, and the overall sound is more than present and less ambient. Y'all become more "boom" and less "room."

Threshold	Ratio	Set on	Release
-13.7 dB	ane.3:1	27 ms	128 ms

Fretted Instruments

Electric Bass. The fast set on and slow release in this setting will tighten upwardly the electric bass and give you lot control for a more consistent level.

Threshold	Ratio	Attack	Release
-4.4 dB	2.6:1	45.7 ms	189 ms

Acoustic Guitar. This setting accentuates the attack of the acoustic guitar and helps maintain an even indicate level, keeping the acoustic guitar from disappearing in the track.

Threshold	Ratio	Attack	Release
-6.3 dB	3.4:one	1471 ms	400 ms

Electrical Guitar. This is a setting for "crunch" electric rhythm guitar. A ho-hum set on helps to get the electric rhythm guitar "upwardly close and personal" and gives punch to your crunch

Threshold	Ratio	Assault	Release
-0.1 dB	2.4:1	26 ms	1471 ms

Keyboards

Piano.This is a special setting for an even level across the keyboard. It is designed to help even upward the top and bottom of an acoustic piano. In other words, it helps the left hand to be heard along with the right paw.

Threshold	Ratio	Set on	Release
-10.8 dB	1.9:1	108 ms	112 ms

Synth. The fast set on and release on this setting can be used for synthesizer horn stabs or for bass lines played on a synthesizer.

Threshold	Ratio	Set on	Release
-11.9 dB	1.8:1	0.002 ms	85 ms

Orchestral. Utilise this setting for string pads and other types of synthesized orchestra parts. It will decrease the overall dynamic range for easier placement in the mix.

Threshold	Ratio	Attack	Release
3.3 dB	2.five:1	1.viii ms	50 ms

Stereo Mix

Stereo Limiter. But as the name implies, this is a hard limiter, or "brickwall," setting—ideal for controlling the level to a ii-rails mixdown deck or stereo output.

Threshold	Ratio	Attack	Release
5.5 dB	7.1:ane	0.001 ms	98 ms

Profile. This setting fattens upwards the main mix.

Threshold	Ratio	Set on	Release
-13.4 dB	1.2:ane	0.002 ms	182 ms

Furnishings

Clasp. This is dynamic compression for solo work, especially electric guitar. It gives you that glassy "Tele/Strat" audio. It is a true classic.

Threshold	Ratio	Attack	Release
-4.6 dB	2.4:ane	seven.2 ms	471 ms

Pump. This is a setting for making the compressor "pump" in a desirable way. This effect is good for snare drums to increment the length of the transient past bringing the betoken upwards later the initial spike.

Threshold	Ratio	Assail	Release
0 dB	1.ix:1	1 ms	0.001 ms

Limiters

At the simplest level, a limiter is a compressor that is set to forestall whatever increment in the level of a signal above the threshold. For example, if you take the threshold knob set at 0 dB, and the ratio turned fully clockwise, the compressor becomes a limiter at 0 dB, so that the output signal cannot exceed 0 dB regardless of the level of the input signal. Typically, pinch ratios of 10:one are considered to exist limiting.

A true analog peak limiter is not just a compressor with a high ratio. A compressor'south detector circuit is commonly designed to notice RMS, or average, levels, so transient peaks will usually overshoot a compressor's threshold level. A true superlative limiter employs a detector excursion that responds to peak energy levels and thus reacts faster.

Noise Gates

Noise gating is the process of removing unwanted sounds from a signal by attenuating all signals beneath a set threshold. Every bit described, the gate works independently of the sound signal afterwards beingness "triggered" by the signal crossing the gate threshold. The gate volition remain open up as long every bit the signal is in a higher place the threshold. How fast the gate opens to let the "skilful" bespeak through is adamant by the set on fourth dimension. How long the gate stays open afterward the signal has gone below the threshold is determined by the hold time. How fast the gate closes is determined past the release. How much the gate attenuates the unwanted signal while closed is determined past the range.

Racket gates were originally designed to aid eliminate extraneous dissonance and unwanted artifacts from a recording, such as hiss, rumble, or transients from other instruments in the room. Since hiss and dissonance are not as loud equally the musical instrument being recorded, a properly ready gate will just allow the intended sound to pass through; the book of everything else is lowered. Non merely will this strip abroad unwanted artifacts, information technology will besides add definition and clarity to the desired sound. This is a very popular application for noise gates, especially with percussion instruments, as it will add together punch or "tighten" the percussive sound and make it more pronounced.

Consider the compressed-vocal instance we gave before; you now have a 20 dB dynamic range for the vocal channel. Problems arise when noise or instruments (air conditioner, loud drummer, etc.) in the background of the vocal mic become more than aural subsequently the lower finish of the dynamic range is raised. You lot might effort to mute the song between phrases in an attempt to remove the unwanted sounds; however, this would probably end disastrously. A improve method is to use a dissonance gate. The noise gate threshold could exist set up at the bottom of the dynamic range of the song, say -10 dBu, such that the gate would shut out the unwanted signals between the phrases.

Noise gates are too ordinarily used on on drumkits. If you have ever mixed live audio, y'all know the problems cymbals can create by haemorrhage through the tom mics. As soon as you add some highs to get some snap out of the tom, the cymbals come up crashing through, sending the horn drivers on your loudspeakers into a minor orbit. Gating those tom mics and then that the cymbals no longer ring through them volition give you an enormous heave in cleaning up the overall mix.

Sidechaining and Key Filtering with a Gate

Some Noise Gates, similar those on the StudioLive digital mixers, allow yous to set the frequency at which the gate will open. Setting a specific frequency, in improver to a specific decibel level, provides more sonic shaping. A properly set key filter on a gate can greatly improve the overall sound quality of a mix.

For example, if you are inserting a gate on a snare-drum mic, yous may get plenty bleed from the boot drum to open up the gate. This is where a key filter can come in handy. By setting the key filter to the frequency at which the snare pulsate is resonating, you tin can set up the gate to only open only when the snare is struck. This will filter out all the extraneous noise and give your snare more than presence to punch through the mix with more than impact.

The central filter on StudioLive mixers provides farther command past allowing you to triggered it by the selected channel or bus's signal or past sidechaining it to another aqueduct and using its signal equally the source. This allows you to select a different aqueduct as the trigger source for your StudioLive Gate'due south Key Filter. Sidechaining has many uses, two of the most common are:

Tighten upwards a Rhythm Department. Y'all can utilize a sidechained cardinal filter to tighten upward a rhythm department past sidechaining the kick drum channel to the bass channel and setting the gate to open up at the frequency of the kick drum. This, combined with a fast assail and release, will make your rhythm section more cohesive. Increase the release time to loosen the feel. Delight annotation, that while sidechaining the kick drum to the bass channel tin can tighten up a practiced rhythm department and make them sound fifty-fifty better, it will non correct timing problems and will actually exaggerate them if your bass player and drummer aren't in the pocket.
Rhythmic Result. Another great use for a sidechain is as an effect in EDM production. Effort sidechaining a drum loop to a sustained source, similar pads or strings. Past doing this, every time a drum hit triggers the key filter, your sustained source will be heard. Betwixt hits, this source will exist silenced. Playing with the attack and release volition transform this effect from a rhythmic pulse all the style to a chopped-up stutter.

Noise Gate Components

Assail. The gate attack fourth dimension sets the rate at which the gate opens. A fast attack rate is crucial for percussive instruments, whereas signals such as vocals and bass guitar require a slower assail. As well fast of an attack tin can, on these slow-rising signals, cause an artifact in the point, which is heard equally a click. All gates have the power to click when opening but a properly set gate will never click.
Hold. Concur time is used to keep the gate open up for a fixed period after the point drops below the gate threshold. This can exist very useful for furnishings such equally gated snare, where the gate remains open after the snare hit for the duration of the concord time, then abruptly closes.
Key Filter. The Key Filter is a filter with a variable frequency that allows y'all to remove problem frequencies from the gate'due south trigger signal. Let's say you want to gate the snare drum so that the gate opens every time the drummer hits the snare, letting the snare through, and so closes again. That can be used as an effect or simply so that the noise leaking into the snare mic won't dirty up the overall sound. To make the gate open, y'all use a copy of the dry bespeak from the snare mic to trigger the gate, allowing the snare sound to pass. The problem is, other instruments – notably cymbals – oft leak into the snare mic, and they could accidentally trigger the gate. The primal filter enables y'all to filter out the high frequencies in the cymbals and so that only the snare indicate remains to trigger the gate.
Cardinal Listen. Key Listen lets you audition the gate's trigger point so y'all can adjust the Key Filter's frequency control until the problem frequencies are eliminated.
Range. The gate range is the amount of gain reduction that the gate produces. Therefore, if the range is set at 0 dB, there will exist no alter in the indicate every bit information technology crosses the threshold. If the range is gear up to -threescore dB, the signal volition be gated (reduced) past 60 dB.
Release. The gate-release time determines the rate at which the gate closes. Release times should typically be ready so that the natural disuse of the instrument or vocal beingness gated is not affected. Shorter release times aid to clean up the dissonance in a signal but may cause "chattering" in percussive instruments. Longer release times usually eliminate "chattering" and should exist set past listening carefully for the about natural release of the point.
Threshold. The gate threshold sets the level at which the gate opens. Essentially, all signals above the threshold setting are passed through unaffected, whereas signals below the threshold setting are reduced in level past the corporeality gear up by the range control. If the threshold is set fully counterclockwise, the gate is turned off (always open), assuasive all signals to pass through unaffected.

Expanders

The major difference between expansion and dissonance gating is that expansion is dependent on the signal level after the level crosses the threshold, whereas a true dissonance gate works independently of a bespeak'due south level beyond the threshold.

In do, expanders and noise gates are used virtually identically. The master difference is that an expander is smoother and more gradual, and so that it is easier to set the assail and release times correctly.

Expanders can be divided into 2 categories: Dynamic and Down.

Downward Expansion. Downward expansion is the virtually common expansion used in live sound and recording. In dissimilarity to compression, which decreases the level of a indicate afterward it rises above the compression threshold, expansion decreases the level of a point after the signal goes below the expansion threshold. The amount of level reduction is adamant past the expansion ratio. For instance, a ii:1 expansion ratio reduces the level of a signal by a factor of ii. (due east.thou., if a level drops 5 dB below the expansion threshold, the expander volition reduce it to x dB beneath the threshold.)

Normally used for noise reduction, expansion is very effective every bit a elementary noise gate. The major divergence betwixt expansion and noise gating is that expansion is dependent on the point level later on the level crosses the threshold, whereas a true dissonance gate works independently of a bespeak's level beyond the threshold.

This type of expansion reduces the level of a signal when the signal falls below a set threshold level. This is nigh common used for dissonance reduction.

Dynamic expansion. This is basically the reverse of compression. In fact, broadcasters utilise dynamic expansion to "disengage" pinch earlier transmitting the audio signal. This is commonly referred to as companding or Compression followed by expANDING.

Expander Components

Because an expander is very like to a noise gate, you volition notice that information technology has about, if non all of the aforementioned controls, performance much the aforementioned as they practice on a noise gate. The exception is the Range control, this is a control you will discover on a Noise Gate only.

Expansion ratio. The expansion ratio sets the amount of reduction applied to a point one time the bespeak has dropped below the expansion threshold. For example, a 2:1 expansion ratio attenuates a point 2 dB for every ane dB information technology drops below the threshold. Ratios of 4:1 and college act much like a noise gate but without the ability to tailor the assail, concur, and release times.

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Source: https://www.presonus.com/learn/technical-articles/How-To-Use-Dynamics-Processing-Getting-Started-With-Compressors-Gates-and-More