Top 9 Best Tips For Compressing Pianos & Keyboards


The versatility of pianos and keyboards spans many genres and songs. Compression is sometimes necessary when mixing these instruments to fit them perfectly in the mix. When it comes to compressing piano and keyboard instruments, there are no simple step-by-step instructions; every mix is unique. However, there are certain considerations we should take into account when compressing piano and keyboard, which is what this article is all about.

Before we go any further, I should state that there are no hard rules with compression or any other mixing process. The tips mentioned in this article are simply suggestions and techniques worth considering when compressing piano and keyboard instruments. There are no procedures that work 100% of the time, and every mix is unique in its own needs.

Here are 9 pro tips for compressing piano and keyboard:

  1. Know when not to compress the piano or keyboard
  2. Consider the role of the piano or keyboard in the mix
  3. Consider how the piano or keyboard was recorded
  4. Always A/B test
  5. Compression for colouration
  6. Consider serial compression
  7. Think EQ before or after compression
  8. Make room for the vocal
  9. Use your ears

Let's discuss each of these tips in more detail to give you important considerations when compressing piano and keyboard instruments in your mixes.

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Know When Not To Compress The Piano Or Keyboard

Let's start by considering whether we should be compressing a piano or keyboard instrument, to begin with.

If the piano/keyboard performance was recorded with the song's long-term dynamics in mind, it might be the case that we won't need to compress its dynamic range to have it sit well throughout the mix. However, if the loudest parts of the performance are too loud and/or the quietest parts are too quiet, compression can help smooth out the piano or keyboard track.

Also, consider the genre of the music you're mixing and the typical mix aesthetic for the entire mix and the piano/keyboard. A classical piece recorded in a beautiful room will likely not warrant compression. Conversely, a modern pop song featuring electric keyboards may require significant compression to have it sit consistently in the mix sections where it's present.

Because there's such a variety of sound patches for electric keyboards, we should also consider the sound of the instrument along with the actual audio of the keyboard track.

While acoustic pianos tend to be open and transient with a nice variety in their waveforms, some keyboard patches are rather square-like in their waveforms. The more an audio signal is distorted and resembles a square wave, the more naturally compressed it is. It's often the case that compression won't do much to help with these kinds of signals (though that's not to say we should avoid compressing distorted keyboards).


Consider The Role Of The Piano Or Keyboard In The Mix

The second tip I have for you is to consider the role of the piano or keyboard in the mix. Is it a solo piano performance, a singer-songwriter piece with piano/keyboard and vocals, a full-band situation or perhaps a pop song with a bit of piano/keyboard as an element?

If the piano is the only instrument, we may want to maintain all of its dynamics by not using a compressor. On the other hand, a bit of compression can help tame its dynamics for smoother levels throughout the song. Heavier compression could also be used if that's the mix aesthetic we're going for (though it's generally best to use a more subtle approach).

When dealing with solo keyboard instruments, we'll want to assess the sound of the instrument and decide whether compression will help or not in the context of the mix at hand. A bit of experimentation may be required here.

In singer-songwriter mixes, we may want the piano or keyboard to sit a bit behind the vocal, and compression can help us to do so by taming down the transients. In general, taming the transient information of an instrument will have the effect of pushing it back in the mix.

In a full-band mix, we may need to use compression to keep the piano/keyboard present across the different sections of the mix. We should also consider the role of the piano/keyboard in the song in question.

The same ideas can be expanded to other mixes, whether they're sparse or dense. Consider the role of the piano/keyboard and determine which compression moves (if any) will help fit the instrument into the mix.


Consider How The Piano Or Keyboard Was Recorded

It's always good to know how the instruments of our mix sessions were originally recorded. While listening critically in solo can give us a good idea, affirming the steps used in the recording is best.

Was the piano or the keyboard amp/cabinet miked up, or was the signal recorded directly from a keyboard output? If the piano or keyboard was recorded with microphones, what was the acoustic environment like and how many other instruments were performing simultaneously (if any)? Were any processors, including compressors, in-line that were printed into the recording?

These are all questions worth answering when it comes to compressing a piano or keyboard instrument.

If the piano/keyboard was compressed on the way in, it might be the case that we won't need to compress it at all. Note that distortion-type effects also have a compression-like effect on audio.

Furthermore, the original recorded signal of the piano/keyboard is likely to be the most natural sounding. Of course, we can clean up issues of noise and resonance with EQ.

However, applying compression can lead to slight-to-overbearing degradation of the signal and make it sound less natural in the mix. So if you want an open, natural-sounding piano or keyboard, consider not using compression (or light compression if it's needed).

If the piano or keyboard was miked up and recorded simultaneously and in the same space as the vocal and other instruments, we ought to be aware of the bleed from these other sources in the piano/keyboard track.

Because compression reduces the dynamic range of a signal, it will have the effect of bringing up the quiet parts of the signal relative to the loud parts. This applies to the wanted signal (typically loud) and the noise or bleed of the environment (typically quiet).

So when it comes to compressing the piano/keyboard, we should be wary of any bleed and how we'll be bringing it up in the track with compression.

If, on the other hand, we're dealing with a dynamic and clean signal directly from a keyboard, we could likely get away with more compression before negative side effects begin to arise.


Always A/B Test

A/B testing is one of the best habits you can get into when processing anything in a mix, let alone the compression of a piano or keyboard.

A/B testing effectively tests two options (option A and B) and compares the two to make an informed decision on which is better. We can A/B test by turning the piano/keyboard compressor on and off (bypassing it).

Whenever we make any adjustments to a compressor, it's worth A/Bing them against the original signal and listening to whether the compression improves the sound of the piano/keyboard in the overall mix or not.

When A/B testing, bypass the compressor and listen for about 10 seconds. Turn it back on and listen for another 10 seconds. Repeat the process and decide whether to keep the compressor, readjust it, or get rid of it.

The human auditory system tends to adjust to whatever we're listening to. When mixing, we can quickly lose perspective and our objective decision-making skills. As we adjust parameters to achieve balance and any other goals in the mixing process, we can quickly lose our frame of reference of what good piano/keyboard compression actually is.

So use A/Bing to your advantage when compressing the piano or keyboard instruments in a mix.

If you're interested, be sure to check out my video on the top 5 A/B tests worth incorporating regularly into your mixes:

To learn more about A/B testing, check out my article A/B Testing & Its Importance In Mixing (With 5 Best Tests).


Compression For Colouration

In addition to the main purpose of automatic gain reduction, compressors will have the effect of colouring the sound. While some compressor plugins are programmed to be as transparent as possible, many other plugins, and certainly hardware compressors, will impart their own sonic imprint on the audio signals passing through them.

This colouration is sometimes experienced as an inherent EQ curve, though perhaps more obviously, it's experienced as harmonic saturation, where new harmonic information is effectively added to the signal due to the distortion of the components (or programming) of the design.

Such colouration can help to enhance the character of the piano or keyboard. Utilizing compression in this way for its characteristic “sound” is commonplace.

It may even be the case that we introduce a compressor in-line without applying any gain reduction only to add colour to the vocal.

One issue is the inherent noise caused by hardware compressors and analog plugin emulations. We must ensure proper gain staging to achieve a solid signal-to-noise ratio. This means we must drive the compressor with enough signal level to avoid excessive noise relative to the signal while also keeping the signal level low enough to avoid excessive distortion.

For more information on gain staging, check out my article Mixing: What Is Gain Staging & Why Is It Important?

On top of the inherent sonic characteristics of certain compressors, the actual gain reduction applied by the compressor will also obviously alter the sound. This way, we can apply subtle amounts of compression to add a bit of extra character to the piano or keyboard.


Consider Serial Compression

Serial compression, as the name would suggest, is having multiple compressors in series within a defined signal path. In other words, having a compressor's output feeding another compressor's input (and so on) somewhere down the line.

Serial compression could be as simple as inserting two compressors on a single piano track or having a single compressor on a keyboard track that's ultimately being fed through a mix bus compressor. It could involve many more compressors in any given signal chain (a track into a bus into a mix bus, etc.).

To keep things simple for this article, we'll discuss compressors inserted back-to-back on a single piano or keyboard track.

For more information on inserts, check out my article Audio: What Are Inserts? (Mixing, Recording & More).

Serial compression, in this way, is great for not overloading any single compressor. It can sound more natural and shave off more dynamics, leading to more consistent vocal levels without as many unnatural pumping artifacts. We can also get different colours of different compressors (see the previous tip).

Imagine pushing 12 dB of gain reduction on a single compressor. Chances are the piano or keyboard will sound pretty “squashed” and unnatural. The transient information will likely suffer along with the sustain. Although it can be done in some mixes, it's typically a losing battle attempting to get that much gain reduction without these negative side effects.

However, if we were to utilize two compressors to compress 6 dB of gain reduction each, we'd be able to get more natural results. The first compressor would tame the peaks, and the second would help round out the remaining higher-amplitude moments.

What if we applied that same 12 dB of gain reduction over three compressors (4 dB of gain reduction each) or four compressors (3 dB of gain reduction each)? When done correctly, it would lead to even less pumping, giving us a more natural sounding compression and a more consistent sound.

Try this out for yourself the next time you need a significant amount of piano or keyboard compression to fit these instruments in the mix appropriately.

I talk about and demonstrate serial compression in more detail in one of my YouTube videos that you can check out here:


Think EQ Before Or After Compression

Compressing before or after EQ is largely a matter of taste and is often subtle in the differences it provides. But, when it comes to nice, open, harmonically-rich piano parts or dense keyboard patches, we may want to consider, or at least experiment, having compression before or after EQ.

In general, compression before EQ offers a cleaner, sharper result.

Compressing a piano or keyboard before EQ gives us less control over what the compressor reacts to but more control over the tonal balance of the piano/keyboard. Note that the EQ should be applied more sparingly here since the audio has already been smoothed out.

In general, compression after EQ will yield a smoother, warmer result.

EQing a piano or keyboard before compression lets us shape the frequency content more aggressively, knowing that the compressor will help smooth it out. It's also good to control what the compressor “sees” and reacts upon.

Since pianos and keyboards tend to have a great range of harmonic frequency content, utilizing both EQ and compression can often help mix them perfectly.

For more information on EQing pianos and keyboards, check out my article Top 11 Best Tips For EQing Pianos & Keyboards.


Make Room For The Vocal

Frequency masking is one of the most common and problematic issues in mixing. It happens when two or more tracks compete in similar frequency bands and effectively mask each other in the mix. Neither track, then, is heard clearly as a distinct sound source. Rather, within the band of high competition, the tracks blend together and cause poor separation.

I have a YouTube video dedicated to frequency masking. Check it out here:

While EQ is perhaps the primary tool for tackling frequency masking, we also have a more technical compression technique for the job: sidechain compression.

Put simply; sidechain compression is the technique of inserting a compressor on one track but having another track control the amount of compression.

The sidechain signal of a compressor is typically the same as the input/program signal (taken either directly before or directly after the gain reduction circuit (see feedforward or feedback compression). The sidechain signal is effectively converted to a control voltage that controls the gain reduction circuit (the dynamic range compression) of the compressor.

However, in the “sidechain compression” technique, we utilize an external sidechain signal to control the gain reduction circuit.

Here's a basic diagram of a feedforward compressor with a switch to toggle between an internal and external sidechain. Hopefully, it helps to clarify what I'm writing about:

So let's say the piano or keyboard competes too much in the mid-range with more important elements (the vocal is a common one, but another lead instrument could also be considered).

It's critical to get these elements working together within the mix, allowing both to be heard as distinctive tracks without too much competition and frequency masking between them.

In this case, we try sidechain compression to attenuate the piano or keyboard slightly to make room for the vocal when it's present and have the piano or keyboard go back to its original level when the vocal is not present.

To use sidechain compression, we insert a compressor on the piano/keyboard track and set the vocal track as the sidechain insert to compress the piano/keyboard whenever it's present.

When done subtly within the mix, the vocal can punch through a bit more without reducing the overall perceived loudness or presence of the piano/keyboard.

I have a video dedicated to using sidechain compression in the mix. Check it out below:


Use Your Ears

Okay, perhaps this tip is a bit too obvious, but we must use our ears when using any processing on any tracks within a mix. This, of course, includes compression on pianos and keyboards.

Any tips I could give you in this article are null and void if they don't serve your tastes or the mix as a whole. It's impossible to give instructions about specific parameter settings because every mix will demand something different.

While I can give you good starting points and general advice, the best piece of advice I could ever give you when compressing a piano/keyboard is to use your ears.

If the piano/keyboard compression doesn't sound good or serve the mix, either get rid of it, change the compressor being used, or adjust the parameters of the current compressor. Rely on your ears (along with A/B testing) to get the best results!


Other Compression Tips For Common Elements

Be sure to also check out my top overall 11 compression tips for mixing in this video:


Determining the best compressor for your audio needs takes time, knowledge and effort. For this reason, I've created My New Microphone's Comprehensive Compressor Buyer's Guide. Check it out for help in determining your next dynamic range compressor purchases.


This article has been approved in accordance with the My New Microphone Editorial Policy.

Arthur

Arthur is the owner of Fox Media Tech and author of My New Microphone. He's an audio engineer by trade and works on contract in his home country of Canada. When not blogging on MNM, he's likely hiking outdoors and blogging at Hikers' Movement (hikersmovement.com) or composing music for media. Check out his Pond5 and AudioJungle accounts.

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