Old 06-21-2009, 01:43 PM   #1
357mag
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Okay I just finished up a new song and this time instead of putting Ozone on the Master Bus what I did was to simply put my Kjaerhus Golden Audio Channel Compressor on the bus along with an Exciter. Sounds pretty darn good and I'm happy with the results.

But I do have a question just to satisfy my curiosity and understanding of the Compressor. I'd like to find out how much I'm compressing the signal on the Master Bus. Right now my Threshold dial on my Compressor goes from the left at -40 to the right at 0. I currently have the Threshold set to -16.0 db.

I've noticed as I turn the Threshold to the left more the sound gets quieter and if I turn it to the right it gets louder.

What I would like to know is at a Threshold of -16.0 db am I using:

1. A lot of compression...
2. A medium amount of compression...
3. A little compression.

I just want to understand and find out how much compression I'm using at the Master Bus with my Threshold set the way it is.
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Old 06-21-2009, 01:52 PM   #2
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Quote:
Originally Posted by 357mag View Post
What I would like to know is at a Threshold of -16.0 db am I using:

1. A lot of compression...
2. A medium amount of compression...
3. A little compression.
This would depend on the level of the audio reaching the master. If it lies below -16dB it wouldn't be compressed at all. So I guess the question is not answerable with the current info... What is your RMS? The peaks?
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Old 06-21-2009, 08:22 PM   #3
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When I look at the Master Track it looks like the RMS keeps hovering at 0 and the Peaks are a little above 12.

The input gain meter on my Compressor looks like it flashes from -6 to 0.

Last edited by 357mag; 06-21-2009 at 08:30 PM.
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Old 06-22-2009, 02:49 PM   #4
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I've been thinking (yes, it happens! :-) more about your question, "how much compression", and I don't think it can be meaningfully answered. The reason is that there is no useful metric for determining "how much".

I know you already know how a compressor work, probably better than me, but still...

At least three things affect the "how much":
1. The threshold, which determines when compression gets applied
2. The ratio, which determines the amount of compression.
3. The input level, if it peaks above the threshold it is compressed.

The ratio is essentially a multiplicative factor applied to whatever peaks above the threshold. Thus, setting ratio to 1 will give no compression whatever the threshold and input level. Likewise, setting the threshold to -16dB, say, for input that never peaks above that will give no compression.

So, "how much" must be somehow measured in relation to the threshold vs the input level, as well as to the ratio. How this should be done to be quantitatively meaningful, I don't know.
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Old 06-22-2009, 03:54 PM   #5
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Add two copies of the JS VU meter plugin, before and after your comp, and then compare the two. That's how much you're compressing.
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Old 06-23-2009, 01:17 AM   #6
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Add two copies of the JS VU meter plugin, before and after your comp, and then compare the two. That's how much you're compressing.
Ah! Good point.
Never mind my technical rant about metrics and whatnots. Use your eyes and ears :-)

You could also use GComp, now that I think of it. GComp shows the compressed waveform overlayed on the uncompressed (http://www.gvst.co.uk/gcomp_screenshot.htm). Very nifty...
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Old 06-23-2009, 02:19 AM   #7
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Quote:
Originally Posted by Lokasenna View Post
Add two copies of the JS VU meter plugin, before and after your comp, and then compare the two. That's how much you're compressing.
Just to add - 'As long as you're not using make up gain'


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Old 06-23-2009, 02:23 AM   #8
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I recommend level matching the compressed with the dry so that you can actually hear what it's doing. Just use the gain on the compressor to bring the compressed signal up to the same audible volume as the non compressed. Then bypass the effect and listen.

You need to know what the compression sounds like before you can judge how much. There are no real threshold presets for compressors it's all input level dependant.

Don't be swayed by volume.
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Old 06-23-2009, 06:03 PM   #9
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Of course I'm using make-up gain. That is one of the things you do with a compressor is add make-up gain correct?

Where do I add these JS Plug-ins? On the Master Bus? Do you stick one at the top of the effects window before the Compressor and then one below the Compressor so that puts them in the correct places in the signal chain?
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Old 06-24-2009, 09:45 PM   #10
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Compressors usually have a gain reduction meter that displays exactly what you are looking for. On GAC it is the meter labeled "gain" in each COMPRES box.

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Old 06-26-2009, 08:00 PM   #11
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Mine flashes from -5 to -6. So does this mean I am compressing -5db?
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Old 06-27-2009, 02:07 PM   #12
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Quote:
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Mine flashes from -5 to -6. So does this mean I am compressing -5db?
yes. And If you bring the threshold up to 0 or set the ratio to 1:1 you should get 0dB compression.
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