How compression is used in the studio

[Cbdb2]

There seems to be some confusion about dynamic compression/limiting. This video shows how and why compression is used while recording and mixing music. This is not about the loudness wars, thats usually done with limiters while mastering.

 

[Mtbf]

Rick Beato is great

 

[MaxwellsEq]

Post in thread 'Is audio file compression just decreasing dynamic range?' https://audiosciencereview.com/foru...t-decreasing-dynamic-range.39419/post-1389565

 

[SSS]

Rick explained it very well and comprehensive. Seems to have great experience with all kind of compressors.

 

[MaxwellsEq]

You won't find a professional music sound engineer that isn't completely au fait with compressors. From the late 1970s onwards, big recording consoles such as the SSL 4000E range had a compressor and compressor+gate (e.g. used for gated-reverb on Peter Gabriel's 'Intruder') in every channel! For a 24 channel desk, that's 24 compressors just in the channels as well as several external pluggable compressors with varying characteristics that could be applied to channels, groups or buses.

These days, everyone wants to recreate the sound of early compressors. There seem to be more compressors on the professional market than DACs or IEMs in the home entertainment market:

Sound On Sound - Compressors

 

[SSS]

As Rick describes, many of the compressors can be emulated by using software plug-ins. Nowadays working with a digital workstation there may not be a need for hardware compressors. Hardware, If not silicon, the matching of the vari-µ tubes is not easy since some types are not produced anymore. Once I tried to match for a Fairchild 670 clone the tubes which was only possible to some extent to get same behaviour on both channels. Interesting was the repair of the RCA BA-45 AGC compressor/expander within a microphone preamp. This one uses a small light bulb with a photoresistor. The attack is therefore limited to the lightening uptime.

 

[DVDdoug]

As Rick describes, many of the compressors can be emulated by using software plug-ins.

It should be possible to emulate any of these in software if you can get-hold of a working sample.

And you can do things digitally that were impossible in hardware... The Audacity limiter uses look-ahead so it doesn't distort the wave shape. (Of course it's working on digital files and you can't look-ahead with real time processing.)

Nowadays working with a digital workstation there may not be a need for hardware compressors.

A hardware limiter can be helpful when recording/digitizing to prevent hard-clipping of the analog-to-digital converter. If clipping happens during digitization it's too late... Regular computers are also "tricky' in real time because the multitasking operating system means you need a buffer and a buffer is a delay. You can sometimes get down to a few milliseconds of latency but you can't eliminate it. On the other hand, a stand-alone digital processor can work without an operating system, or it can use a real-time operating system.

Once I tried to match for a Fairchild 670 clone the tubes which was only possible to some extent to get same behaviour on both channels.

And I'm sure there were unit-to-unit variations, especially with the tube or optical designs. So... Which sample are you going to emulate?

I once read a review of a vintage microphone clone. The reviewer had two samples of the original microphone and they measured differently so the clone was closer to one than the other.

 

[MaxwellsEq]

As Rick describes, many of the compressors can be emulated by using software plug-ins. Nowadays working with a digital workstation there may not be a need for hardware compressors. Hardware, If not silicon, the matching of the vari-µ tubes is not easy since some types are not produced anymore. Once I tried to match for a Fairchild 670 clone the tubes which was only possible to some extent to get same behaviour on both channels. Interesting was the repair of the RCA BA-45 AGC compressor/expander within a microphone preamp. This one uses a small light bulb with a photoresistor. The attack is therefore limited to the lightening uptime.

Nice to read about someone else repairing and lining up compressors and limiters. They are strange beasts - normally you are trying to minimise noise and distortion and maximise linearity, but not with compressors.

 

[Blumlein 88]

So, how many acts of compression would your average song have applied to it? To say nothing of reverb, EQ, delay and more. And people worry if the song is presented in 16 bit or 24 bit formats and whether a lousy SINAD of -90 db is any good. Ha!

 

[kongwee]

Nice to read about someone else repairing and lining up compressors and limiters. They are strange beasts - normally you are trying to minimise noise and distortion and maximise linearity, but not with compressors.

Because you really did in the source, sample, mic, mic pres before send your signal to compressors. Your compressor just need to, well to compress.

 

[Keith_W]

So the impression I got from that video as to "why use compressors", instead of the loudness wars, the example given was "if your drums are too soft, we use compression to even out the volume of the sound". In that case, isn't it the musician's fault for playing the drums too soft and too loud at times? In classical performances, it is the conductor's job to make sure that instruments or groups of instruments play at the correct tempo, volume, and expression. I realize it's not the same in other types of music, most notably electronic music where it seems as if almost all the work is done by the sound engineer.

If drummers don't know how to drum, or singers can't sing, then their lack of talent should be on the recording for all to hear. This is part of the malaise that inflicts modern music, you are all too aware that you are listening to a slick production and there is no humanity left in it.

 

[Groom]

This is part of the malaise that inflicts modern music, you are all too aware that you are listening to a slick production and there is no humanity left in it.

I don´t know exactly when the era of "modern music" began for you but compressors are used since the 1930s...

First in public adress systems, then in broadcasting and recording.

Autotune on the other hand...

 

[Keith_W]

I don´t know exactly when the era of "modern music" began for you but compressors are used since the 1930s...

First in public adress systems, then in broadcasting and recording.

I am aware of that. Public address systems and broadcasting do require compression for audibility. The limitations of analogue recording and vinyl meant that compression was necessary. However, with digital's much superior dynamic range, why do we need compression except for the loudest sounds (like gunshots, cannon, airplanes taking off)? The only reason stated in the video was to correct the performance of bad musicians. Are there any good reasons to use compression?

 

[Groom]

Of course.
You can use it creatively to colour or shape all kinds of sounds, even support or modify the groove.
Mastering all the different kinds of compressors is an artform and can do wonders in the right hands. No matter if it´s electronic music, rock or Jazz.
There are special compressors that are used in classical music as well.

All for the benefit of the listener. Not to brickwall anything but to tame overly dynamic music and make listening a pleasure.
For extremely loud burst like those you´ve mentioned, I much prefer automation or manual editing over compression, btw.

 

[Blumlein 88]

I am aware of that. Public address systems and broadcasting do require compression for audibility. The limitations of analogue recording and vinyl meant that compression was necessary. However, with digital's much superior dynamic range, why do we need compression except for the loudest sounds (like gunshots, cannon, airplanes taking off)? The only reason stated in the video was to correct the performance of bad musicians. Are there any good reasons to use compression?

So people can listen to and hear recordings. I did some recordings of a friend's music group, used a pair of good microphones and no processing other than a touch of EQ. I thought it sounded great on my home system consisting of Soundlab ESLs. Lots of good image and soundstage with a nice sense of spaciousness. Did not go over too well. Everyone wanted to be able to hear it in their car. Turn it up enough to hear it and peaks would overload the car amps. Turn it down and half the music was buried in noise. I think my next version had 2.5:1 compression and they liked it. I then used 3:1 and they liked it better and could hear it enough they were happy. I thought the 2.5:1 was better even in the car, but they didn't.

That sort of thing is the original reason for compression and why you need it. Lots of good recordings can sound lackluster and lifeless without it too.

Now all the stuff in the video is where it gets to be a creative thing and allows you to create dense mixes with lots of tracks and at least sometimes hear it all. Giving drums an unreal kind of a kick, and many other things.

Consider a car at highway speeds is maybe 70 dbSPL. If you limit yourself to 105 db peaks and assume you can usefully hear 15 db into the noise then you are talking a 50 db range. Incidentally testing I've seen indicates if you have about 50 db of dynamics that makes speaking good, clear and easy to understand.

 

[Inner Space]

The only reason stated in the video was to correct the performance of bad musicians. Are there any good reasons to use compression?

Very few bad musicians make it into the studio. But they still need compression because, for one reason or another, some instruments are very inexact. The bass guitar, for instance (which I play) is a ridiculous instrument musically. String-to-string amplitude variation is huge, weird overtones can overwhelm the fundamental, and so on. I have never recorded a bass without compression (or played one). Modern drumsets have similar problems. It's not that the drummer has no touch - it's that to develop the full envelope of a drum sound needs a decent smack to set it off, which will be way too loud for domestic reproduction.

 

[kongwee]

So the impression I got from that video as to "why use compressors", instead of the loudness wars, the example given was "if your drums are too soft, we use compression to even out the volume of the sound". In that case, isn't it the musician's fault for playing the drums too soft and too loud at times? In classical performances, it is the conductor's job to make sure that instruments or groups of instruments play at the correct tempo, volume, and expression. I realize it's not the same in other types of music, most notably electronic music where it seems as if almost all the work is done by the sound engineer.

If drummers don't know how to drum, or singers can't sing, then their lack of talent should be on the recording for all to hear. This is part of the malaise that inflicts modern music, you are all too aware that you are listening to a slick production and there is no humanity left in it.

Not exactly on dynamic. Drum for example, you can use compressor to change the transient and decay behaviour and make a unique "timbre" out of it. That why you have so many kind of compressor. It is not just to volume up the drums.

Another common use of drum compression is actually on the bass guitar. When the kick drum hit, the compressor will soften the bass guitar to have more "impact". Practically you do not want to do this by drawing the volume dynamics. This is call sidechain compression. Also used in radio broadcast, if you wanna reduce background music when you start to speak.