Why both compression and limiting?

[Devon8822]

How come it it typical to use both compression and heavy compression(limiting) on master tracks? What does this accomplish? thanks!

[mdoelger]

Basically you'll wnat to set the compressor to either even out a mix, glue it together or enhance its emotional "content" through the manipulation of dynamics.

The limiter is most of the time the last thing in the chain and used to prevent any short peaks from going over (historically, nowadays it's used to push loudness beyond sane levels.)

[wado1942]

Limiting is used primarily to reduce peaks of the program material either to protect against clipping or to raise the overall level without greatly affecting the bulk of the dynamic range. Compression is used more to sculpt the overall sound to add a little punch or to smooth out certain aspects of the dynamic range. By the book, though, limiting is just compression with a very high ratio (like 10:1 or greater). I frequently limit without compression and vice-verse.

[Rob Murray]

Compression and Limiting are very different.

We're not talking about the classical definition of limiting being a compressor with a ratio of greater than 8:1 but about brickwall look ahead limiters. These limiters "look-ahead" at what's going to come, and react in advance ensuring that nothing goes above the threshhold. Thus the name brickwall, as it's literally a ceiling that can't be passed. Because of this it allows one to remove peak transients (and more) from a digital recording, pushing the overall level higher without clipping.

When we talk about compression in mastering, we're talking about regular old run of the mill compressors as you're used to. These can be helpful in setting a tone, and gluing a piece together, but in general the level gained in mastering mostly comes from the limiting. Again, generally, of course compression, saturation, EQ, etc. count as well, but the largest part is coming from the brickwall limiter.

It's hard to say there's a rule of thumb, but normally compression in mastering is only a dB maybe 2, usually pretty slow attacks, compared to mixing, anything more is usually considered pretty extreme, and this usually leaves most original transients roughly intact, whereas limiting very clearly lowers/limits transients and may gain you 6dB in some cases or even more.

To add to the confusion, there's of course other possibilities, many people use analog limiters as well, which although aren't brickwalls, may help get a dB or two extra, in a different way than a brickwall, and there's of course multi-band compression/de-essing/acceleration limiters which all can be handy in certain situations.

[Franco]

I don't think Compression is "typical" in mastering. Limiting, almost always and even with that, sometimes it's just there to catch peaks with little GR unless the goal is to decrease dynamic range for the sake of loudness. I've done a few projects where we focus primarily on tonal balance for translation and use a limiter only to catch any overs (especially when the medium is vinyl).

[basmartin]

A compressor with slower attack time, actually brings out some transients and will overload the mix buss, so then a limiter comes in handy.

[DominicWyeth]

Originally Posted by Rob Murray

but the largest part is coming from the brickwall limiter.

I must be doing it wrong. I'm normally not pushing the limiter at all. Just setting a ceiling.

[DominicWyeth]

Ie. there are more than three ways to skin a llama.

[jonathan jetter]

compression is either for vibe/motion, or for gentle leveling from section to section.

limiting is purely for overall level increase, or once in a while if you have too much transient content for your own good.

[ritelec]

Originally Posted by DominicWyeth

Ie. there are more than three ways to skin a llama.

Sometimes more than six.

[Devon8822]

Originally Posted by mdoelger

Basically you'll wnat to set the compressor to either even out a mix, glue it together or enhance its emotional "content" through the manipulation of dynamics.

The limiter is most of the time the last thing in the chain and used to prevent any short peaks from going over (historically, nowadays it's used to push loudness beyond sane levels.)

I understand why you would use insert compression on individual instruments and how less dynamics on vocals or drums would help the sound but wouldn't you "even out a mix" with volume already rather than more compression?

Do AE's generally put more compression on during mastering even if they have it on individual instruments already, or is it more just if there isnt other compression on instruments?

[sat159p1]

I use compressor as a glueing tool, and limiter to catch peaks. I almost never use compressors to tame peaks (fast settings), maybe that happened few times where the drums were too loud.

[mdoelger]

I think you are confused about what mastering actually is.

It's not (necessarily) what you put on your master buss when mixing.

You as a mixer send a good sounding mix to the mastering engineer. He's gonna review it and treats it with processing as a whole. He doesn't have access to the individual channels anymore. As he listens in a Perfect environment he can spot problem which you as a mixer couldn't, maybe. This could be for example too much dynamics. Like when you're mixing loud all the time your drums will most likely end up too loud. Don't ask me why. The ME then maybe can press the drums a little bit back into the mix.

Compression isn't used evertime during mastering. And when it's used it mostly for enhancing the feel of the song.

[craze3]

Originally Posted by Devon8822

Do AE's generally put more compression on during mastering even if they have it on individual instruments already, or is it more just if there isnt other compression on instruments?

Really good question, I would also like to know the answer to this

[mdoelger]

this place has become a real mess lately.

[Riccardo]

Originally Posted by craze3

Really good question, I would also like to know the answer to this

Originally Posted by Devon8822

I understand why you would use insert compression on individual instruments and how less dynamics on vocals or drums would help the sound but wouldn't you "even out a mix" with volume already rather than more compression?

Do AE's generally put more compression on during mastering even if they have it on individual instruments already, or is it more just if there isnt other compression on instruments?

There is no set rule. The mixer does his/her job using compression when and where he/she feels it is needed be it for artistic or technical reasons.
Contrary to widespread urban myths compression is seldom used in mastering and when needed it will be very light. Same goes for digital limiting. Bar a few exeptions where the client firmly requests smashing it to pieces the digital brickwall is likely to show a gain reduction of 1 to 1.5 decibel