Just a question about Compression Ratio.

PhilLondon said:
Yea, so I'll have the threshold set to -20 and nothing, then to -10 and it does, then I was trying to add compression to a snare and it only became compressed when I lowered the threshold, back to -30, -40. I don't get it. Maybe the volume was too low?

Are you kinda saying just set the ratio to not too extreme a number and then play with the threshold, and the compression will kick in and I'll hear it and can go by ear, regardless of understanding it? ..
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You said vocal earlier. 10ms attack is likely completely after a snare transient. So the peak could be well above the threshold, but it's too fast for the attack.
A good exercise would be, with a snare and again with the vocal, 10ms attack, set the threshold so it's just starting to show reduction (visual for now), now start decreasing the attack, 8, 6, 4, 2, 1ms.
A lot of the action is in the attack.
Then do it at 2:1 ratio. Still lots of action just in the attack..
 
PhilLondon said:
Yea, so I'll have the threshold set to -20 and nothing, then to -10 and it does, then I was trying to add compression to a snare and it only became compressed when I lowered the threshold, back to -30, -40. I don't get it. Maybe the volume was too low?
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What compressor are you using?
This above description is the reverse of how it should be, and you started off talking in positive numbers.
It's a long shot, but it'd explain a lot if it had some arbitrary numbering system for threshold.

Look for video tutorials on avid/digidesign dyn3 compressor.
It's a great comp in terms of an easy to understand visual representation of what's happening.
 
The problem with trying to deal with specific numbers on a compressor is that there are too many variables for it ever to work out the way it seems it should on paper.

With things like drums, 10ms misses half the hit, so the compressor won't really do much until you get to some extreme (seeming) settings. Especially if the release is quick too.

Vocals are not all the same either. spitty, fast staccato rap vocals will make a compressor react completely differently than an opera singer.

What you are trying to do is set the compressor and then predict what the reduction meter will do. When it doesn't do that, you assume you misunderstand how a compressor works. You understand just fine, you just aren't working in a controlled lab under conditions that will get the text-book results.

Go back and do what someone said earlier: Set the ratio to something like 4/1 and drop the threshold until you see a few db of reduction. Then play with the attack, twist the knob until it sounds right to you. Now play with the release. Does it recover fast enough? Does it recover too fast.

Now lower the ratio to 2/1 and lower the threshold until you have the same amount of reduction you had at 4/1. Notice the difference in the sound of the compression.

Now raise the ratio to 8/1 and raise the threshold until the reduction is the same as it was the other times. Notice the difference in the sound of the compression.

I very rarely use compression to keep the dynamics in check. I use it for the sound of the compression and to shape the envelope of the thing that I am compressing. Snare, for example, I can use a compressor to accentuate the transient, or de-emphasize the transient and make the decay longer. That's the sort of thing I do with compression. Of course, it does tend to tighten up the dynamics in the process.
 
I gave an example of a vocal and a snare.

Sorry if I'm coming across a little contradictory. It's still a little confusing for me. Luckily you seem to have completely made sense of my madness.

I'll give it a go.

The compressor I'm using is the stock Logic Pro X one.
 
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Someone once said to me 'don't worry about the numbers, you understand what It does, just play around with it until you get the desired effect/reduction, you'll understand it through using it'.

Does that sound like good advice?
 
That's the only advice...

In order to make a compressor work for you, you need to know what the different parameters SOUND like when you set them higher or lower. Once you get a feeling for that, you will be able to work any compressor in any situation.

Not all compressors will react exactly the same with the same settings. Not every bass guitar will make a compressor react the same as another bass. Same goes for snare, vocal, piano, etc...

Compressors react to the dynamics of the performance, the frequency content of the instrument and the percussiveness of the audio. So that is a moving target. Every compressor reacts differently even with the exact same settings, so that's a moving target too. The only thing for you to do is recognize the trends... slower attack will make it more....higher ratio will make it more... and just go with it.
 
Okay, it's starting to make sense now, I think.

The signal on the vocal is between -17db & -10 uncompressed. The compressor starts kicking in at a threshold of -28db. The ratio is at 4:1. The release is long at 1700ms .The attack at 5ms leaves the output at -23db to -20db. With it at 160ms the output ends up at -20db to -17db.

So this means that a slower attack allows more of the signal through. The shorter one compresses it faster?

With a slow release with the attack at 5ms the output is -19 to -12. It should be lower, but I imagine that this is because the attack is so fast that the release can't start working?

When I set the attack a little higher to 15ms, and the release to 2000ms the output was -25db to -17db. This is because it allows the release to release it slower, without the attack taking over?

Is this kinda right?

EDIT: I've just realised that this old mix is mixed really loud so I'm gonna have to do all the compression again! ARGH!
 
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Don't get hung up on the output. The amount of reduction is the important thing. If the output is too high or too low, you would fix that with the makeup gain control. Focus on the amount of reduction.
 
If you set the release really long, it doesn't recover before the next transient. So the next transient essentially doesn't do anything because the compressor is still reducing the signal as much as it needs to.

So, if you set the release to 5 seconds, all you are doing is turning the volume down after the initial transient.

If the attack.is too long, the transient will get through and it will turn down the decay.
 
A quick question - Is this okay to do? For example, I've compressed a vocal track and then raised the gain to match the original input, and then afterwards I realise that I need to maybe change the volume of the compressed track, instead of then just raising the volume via the fader, which could affect the compression settings, I have been increasing or decreasing the gain in the compressor. Is this wrong or okay? If it's wrong, why?

Thanks!
 
It's completely normal (and okay) to adjust the over all level of a signal after it's been through a compressor. Indeed, many compressors have a control called "Make Up Gain" which allows you to do exactly this.
 
Nothing wrong with using the gain on the compressor, also called "Make up Gain" (Just ask Miroslav :D ).

But turning it up at the fader won't affect the compressor, at least not in REAPER.
 
I thought that's where the threshold comes into play? Like, if I set the fader at -20dB, it won't react until then, whereas if I put it at -5dB I'd have to set the threshold higher, or am I totally wrong and it's based on the actual input level before fader adjustment?

I'm guessing it's the latter!
 
PhilLondon said:
I thought that's where the threshold comes into play? Like, if I set the fader at -20dB, it won't react until then, whereas if I put it at -5dB I'd have to set the threshold higher, or am I totally wrong and it's based on the actual input level before fader adjustment?

I'm guessing it's the latter!
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It might depend on the DAW or on the routing. But in REAPER, the compressor reacts to the signal pre-fader. You can turn the fader all the way up or down and it won't affect what's being sent to the compressor. The compressor reacts to the original signal.

A good way to test that is to look at your compressor while sliding your fader all the way up and all the way down. When I do it, the compressor doesn't change how much it compresses.
 
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Yea I've just tested it and you're right.

What I've been doing at times is bringing the whole session down so that it's not too loud for mastering (this is probably a confused statement) and then redoing all the compression. Now I don't have to! What a waste of time!

Thanks though!
 
PhilLondon said:
Yea I've just tested it and you're right.

What I've been doing at times is bringing the whole session down so that it's not too loud for mastering (this is probably a confused statement) and then redoing all the compression. Now I don't have to! What a waste of time!

Thanks though!
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There you go. You learn something new every day, sometimes through trial and error.:)

I think the only thing you might have to adjust if you bring all your volumes up or down is the amount of send to pre-fader effects like reverb, for example. What I mean is, you're turning everything down, but the amount of reverb is the same, so it will actually end up giving you more reverb than you want since the dry levels went down but the reverb level stayed the same.
 
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