# Compression



## mikek1357 (Apr 11, 2018)

Hi folks,

I'm a complete newbie to composing and mixing. 

Regarding compression, is it done per instrument, instrument group or whole track?

Thanks for tips and advice!


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## patrick76 (Apr 11, 2018)

It can be done for all of the above, BUT it doesn't need to be automatically applied. It matters a lot what kind of music you are mixing. Some styles use heavy compression like rock and other pop music (and also many trailers) while for orchestral stuff where a large dynamic range is often desired it can be used sparingly (or not at all). 

To oversimplify I would say that if you have an instrument where there are parts that are jumping out a little too much, first try to automate the volume and if that doesn't get you where you want to be, then maybe try compression. For the group or the whole track the primary benefit of the compression would probably be to "glue" the instruments together and make them sound like more of a cohesive whole. Just use a little if you are working with orchestral stuff. Anyway, I'm oversimplifying, but.... 

If you're doing rock or pop compression is often not only used for volume control but also for adding color and warmth to a track. Many of the most famous compressors have tubes in them and can add subtle (or not so subtle) distortion and character to a track.

Have fun experimenting!


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## rrichard63 (Apr 11, 2018)

What patrick76 said. I would add that compression of a whole track usually serves a different purpose from compression of a a single vocal, instrument or group bus (especially common on drum buses). The former is generally about "gluing" a mix together (subtle reverb can do the same thing in a different way). The latter is generally about making something sound "fatter" or "fuller" against the other elements of the mix.

In my experience, compression by itself rarely works to tame erratic jumps in level. For that you need to automate volume changes.

In this area, even more than in other areas, the "rules" need to be broken -- or at least severely tested.


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## SimonCharlesHanna (Apr 11, 2018)

rrichard63 said:


> In my experience, compression by itself rarely works to tame erratic jumps in level. For that you need to automate volume changes.


Ill disagree here: Not sure how erratic we are talking but compressing/taming the levels is literally the definition of a compressor.


mikek1357 said:


> Thanks for tips and advice!


Once you understand *exactly* what compression is and does, you won't really need tips and tricks - you will use it when you need to.


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## Nick Batzdorf (Apr 12, 2018)

Yeah, compressors can do a lot of things.

They can smooth out a mix or individual part, increase density by letting you bring up the floor without distorting the ceiling, tame peaks (once you get to a 10:1 input:output dynamics ratio it's called limiting rather than compression), soften or harden attacks, increase the sustain, make things more punchy, change the timbre depending on how the compressor reacts to certain frequencies...


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## KEM (Apr 12, 2018)

There’s no rule to it, but in my opinion I think it’s always best used on individual tracks or on group tracks. I would recommend not putting a compressor on your master bus, use a maximizer and a limiter instead, that will make your tracks sound huge.


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## aaronventure (Apr 12, 2018)

I'll be blunt, but this might help you more than any "advice" on using compression.

You're essentially asking "Hey guys, do you use the hard brush on crude silhouettes, little details or for huge strokes?" 

Compression is a tool. It has a wide range of uses. Just like there are different types if hard brushes, there are different types of compressors. When and how to use compression is specific to the type of audio you're compressing, and your goals (this would encompass everything from styles and genres to personal taste).

The only way you figure out where to apply compression is to first learn what it does and then move towards your goal. 

Now go and apply compression to a single instrument, then to a group of tracks, then to a whole track. Then try different combinations. Then try different settings. Then try different compressors! Take note of what's happening, how is audio reacting, etc. 

You'll start noticing compression effects in music because you've been studying it. You'll learn how does a pop song sound with little to no compression. And how does orchestral music sound with a lot of compression. 

Eventually you'll develop some uses for compression that might be specific to you, just like some brush techniques are specific to certain painters. Once you learn the techniques, how you use them is completely up to you. 

This is perfectly valid for any other tool you might ask about. 

Seriously though, if you're a complete newbie, there's nothing better than to just delve deep and start clicking buttons and twisting knobs and taking note of what's going on.


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## Henu (Apr 12, 2018)

SimonCharlesHanna said:


> Once you understand *exactly* what compression does



I have been working with hard- and software compressors for the last 15 years and still I find it sometimes impossible to say _what it actually does_ to make the sound exceptionally good or bad.


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## Chris D (Apr 13, 2018)

Thsi might help - https://www.soundonsound.com/techniques/compression-made-easy


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## robgb (Apr 13, 2018)

This guy is a very good teacher:


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## Nick Batzdorf (Apr 13, 2018)

Henu said:


> I have been working with hard- and software compressors for the last 15 years and still I find it sometimes impossible to say _what it actually does_ to make the sound exceptionally good or bad.



I think you absolutely can say what it actually does if you've been using them for 15 years!

This thread and one on Facebook a few days ago make me scratch my head.

Sure it takes practice to use compressors well, because their effects can be more subtle than other processors. But it's not brain surgery, and there's absolutely nothing mysterious about what they actually do and why you'd want to use one - or where in the signal chain to use them.

I listed a few of their applications above.


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## Nick Batzdorf (Apr 13, 2018)

Having said that, there are compressors that are magical because of their color. The LA2A is the most famous example. It can do 15dB of reduction on a vocal and still sound natural.

But you don't need to study the occult to understand what it's doing, it's just nonlinear (its optical circuitry changes the ratio depending on the input).

Optical compression is very clever. The LA2A uses a copy of the signal to be compressed as the control. Higher voltages make a light shine brighter on a panel, causing it to take longer to release the light it absorbs.


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## Henu (Apr 13, 2018)

Nick Batzdorf said:


> I think you absolutely can say what it actually does if you've been using them for 15 years!



Well, technically of course, haha! I'm talking more about the "mojo" and why sometimes something that shouldn't work at all fits like a glove into something.


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## jcrosby (Apr 14, 2018)

Compressors were originally designed to control level inconsistencies in program material in broadcast. They weren't initially designed as an effect or "for mixing"... It can be used to level material, or used to add density or 'compactness' to a sound. Even _improve a performance._ (To borrow a phrase...) It all depends on what you're after...

They can also be used to exaggerate or decrease movement...

As for when... that comes down to aesthetics and experience.
Compression is versatile... And its versatility comes down to compressor choice and/or settings...

The thing to realize about compression is that different models behave differently. And all compression parameters can potentially cause more compression. E.G... If you had a low ratio but decrease attack and increase release time you get more compression. If you increase attack time and reduce release time, but, increase ratio you might also increase compression as well... If you pull down on the threshold you'll increase compression as well...
Basically all parameters have the potential to increase compression, and it 's a symbiotic relationship that takes practice and experience that depends significantly on the compressor chosen...

................
The most important things to understand about compression are:
................

Compressors were originally intended to solve problems. Treat them with that respect in the sense that you don't assume anything _needs_ to be compressed. The choice is a marriage of experience, aesthetics, and common sense...

Some of the most beloved compressors have few controls and are _program-dependent _(LA-2A, 1176, Variable-Mu...) This means that they have the potential to 'adjust' their attack, release or ratio settings depending on what you hit them with and how hard you hit them. This means that depending on what you feed them you can get behavior ranging from gentle and smooth to aggressive and smashed.

Compression is something that you need to train you ear how to hear like anything else. You simply don't set a compressor based on numbers or theory... You need to learn how to _hear_ compression for best results...

All compressors, no matter how "transparent" as they claim to be add distortion. (This includes your "clean" compressors such as Pro-C2. Generally, harmonics can be seen on an analyzer once you cross the threshold...)


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## GtrString (Apr 14, 2018)

A compressor is a tool to work on the peaks of your audio representation. 

Sometimes you'd want to shave off the peaks in order to be able to increase volume, sometimes you'd want to do it because it makes the audio sound smoother, sometimes you'd want to do it because the compressor adds more "dimension" or "density". Sometimes you don't want to use it at all if the track is loud enough, smooth enough, or sound good as is. 

Compression is for sound shaping, problem solving and sound design, but it's a creative tool, so hard rules don't apply.


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## mikek1357 (Apr 16, 2018)

Thanks for all the feedback!! It really is a great help!


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## MarcusD (Apr 25, 2018)

My only tip, which applies to learning how to use most audio tools, is turn your main volume way down. It'll be much easier to hear the effects of each function as you change it and understand how it affects the sound. Sometimes your room makes it hard to hear whats going on, depending on acoustics.


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## Divico (Apr 25, 2018)

This tutorial is also very good. Short and on point


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## Zak Rahman (Apr 25, 2018)

For compression and EQ, watch the Fabfilter guides by Dan Worral.

Best guides ever, in my opinion.

I accept no responsibility if Worral's voice makes you question your own sexuality.


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## pderbidge (May 4, 2018)

mikek1357 said:


> Hi folks,
> 
> I'm a complete newbie to composing and mixing.
> 
> ...


Great question and a lot of good comments. I just wanted to pipe in an say that once I decided to learn how to mix tracks myself, regardless of the fact I had a skilled mix engineer available to work on my tracks for me, I found that learning myself also taught me tricks that helped with composition as well. I now recommend that every composer/songwriter learn the basics of mixing and mastering as it will open a whole new world to you. There's a lot of good free info out there to start with(I'd be happy to recommend some that helped me). Don't get caught up in the hype of buying plugins. What you have in your daw will work just fine. You don't need another plugin until you understand what you have first, and even then keep mastering what you have. Eventually you'll answer your own questions like this, not that it's bad to ask


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## wooolfsounds (May 17, 2018)

As it happens, I recently wrote a post about the basics of compression, aimed at musicians and composers. You don't need to become an expert, but being able to understand what a compressor does and when to use it can certainly help you.

Here it is: http://wooolfsounds.com/index.php/2018/05/03/tools-of-the-trade-the-compressor/

Hope it helps!


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