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Shameless compression questions

Posted: Wed Aug 14, 2013 9:19 am
by aioffermann
So! I feel like I've taken a very odd route around learning production. I used to be working almost exclusively with Samplers. I used to kinda try to do compression the ADSR and gain, when I needed it as an effect almost. Now I'm getting much more into working directly with audio clips.

I just want to see if anyone can tell me if I'm thinking of the controls on the Compressor correctly.

Let's say I have a 909 kick that I want to elongate the tail on.

1. I set the threshold down to the point of decay that I want the new loudness to work on. ->
2 or 3. I set the ratio to control how much louder I want it to beef up/squash
4. I set the attack to indicate how long I want the loudest part.

and Decay is kinda giving me a headache. It seems to me, according to the definition Ableton gives, that the longer the release the longer the loudness increase. But I set it higher and it's quieter.

A little intoxicated to be truthful but was curious if anyone would shed light.

Also I don't get the infinity ratio it doesn't make sense to me :lol: :lol: :lol:

Re: Shameless compression questions

Posted: Wed Aug 14, 2013 10:06 am
by macmurphy
try out this preset for Compressor - http://kiwi6.com/file/d1u4hemj75

you can extend the tail further by turning down the release and threshold.

hope this helps somewhat.

Re: Shameless compression questions

Posted: Wed Aug 14, 2013 1:58 pm
by leisuremuffin
ratio works like this- 4:1 ratio means that for every 4db the signal goes over the threshold, it is allowed to increase by 1db. so infinity:1 just means that the signal should never be able to go over the threshold level.

now, when thinking about the envelope, it's like this- When a signal exceeds the threshold level, the attack is how long it takes the compressor to turn the signal down. so, if your compressor is set to a ratio of 4:1, the threshold is set to -8db, and an incoming signal peaks at 0db, the attack parameter tells the compressor how fast to turn the signal down by 6db. A longer attack time will let some of the peak come through at it's uncompressed volume while the attack envelope takes its time to start turning the volume down. release is the same idea, but its how long the compressor takes to return to normal after the input signal goes back under the threshold.

Re: Shameless compression questions

Posted: Wed Aug 14, 2013 2:17 pm
by Angstrom
LM's description may be misleading a little here.

Compressor envelopes are about rates of change. Where many people become confused about compression envelopes is they are familiar with triggered synth envelopes, where gate signal comes in : Synthesizer envelope starts, then a gate signal ends: Synthesizer release phase starts.

This is not at all how a compression envelope works.

In a compressor envelope : the attack and release govern response time, like rubber bands attached to the input levels. The longer the elastic the less quickly the 'compression' follows what the input does. So a nice short elastic band means that the compressor will start to work quite quickly, a long elastic band means it will respond to any changes slowly.

You could also think of the attack and release speeds as a dopey mix engineer who is meant to be riding a fader. A large value corresponds to a really dopey engineer who doesn't notice that the kick got quiet ages ago. He responds to changes slowly.

SO: once again, the compression envelope is not "triggered" like a synth. The compression envelope is a response-to-change rate for upward and downward events.


Real World Example: A kick with a 2 second tail. We want to tame the initial click and sustain the tail

The confused amateur sets Attack: 1ms, Release: 2seconds under the mistaken assumption "I want a 2 second tail, so I will set the release for 2 seconds". No. What this is doing is saying to the compressor "hey buddy, wait two seconds before you respond to any reduction in input volume". So the compressor is ignoring the change for two seconds.

What the compressor actually needed to do was respond to diminishing volume as soon as possible (without sounding lumpy). It needed to turn up the quiet sounds asap and stop squashing them.

It needed settings more like : Attack: 1ms, Release: 100 milliseconds

the release responds quickly to any diminishing of the input, and acts to apply the correct ratio of compression for that db value

Re: Shameless compression questions

Posted: Wed Aug 14, 2013 3:00 pm
by leisuremuffin
yes, if you want to relate the function to synthesis, the attack and release of a compressor work like an envelope follower or slew with variable rise and fall time rather than like a triggered or gated envelope generator.

Re: Shameless compression questions

Posted: Wed Aug 14, 2013 4:07 pm
by ian_halsall
Not sure if I read OP correctly but the compressor will never make the sound longer than it was originally unless you are using an emulation of an analogue compressor.

The release relates to the time the compressor carries on compressing after the amplitude has gone below the threshold.

So say you are side chain compressing your strings off your kick and you want the kick to have a bit of space before the strings come back up - you give it a bit of release.

Same for attack.