Compression - Ratio?

[Jay Pace]

I don't understand what difference ratio makes to compression.

Attack, release, threshold - fine.

"squash the signal to bring the overall level up" principle of compression - fine

What does ratio do? What applications do you use ratio for, what difference does it make to the sound? I can't seem to hear the difference it makes, on the effect or contribution it has on compression. So a double combo of I don't know what it does, and can't hear the difference it makes - high ration and low threshold sounds pretty much the same as low ratio and high threshold etc.

help?

[rhythmtech]

in simple terms the ratio is the compression amount.

the threshold is the level that this compression starts at.

[Jay Pace]

How do you change the amount of compression? I thought once it hits a certain threshold the signal is compressed. How does ratio vary the amount of compression?

[rhythmtech]

How do you change the amount of compression?

raise the ratio


wiki:

The amount of gain reduction is determined by a ratio. For example, with a ratio of 4:1, when the input level is 4 db over the threshold, the output signal level will be 1 dB over the threshold. The gain (level) has been reduced by 3 dB. When the input level is 8 dB above the threshold, the output level will be 2 dB; a 6 dB gain reduction.

[RDR]

As the threshold drops the ratio has a greater and great effect on the audio levels.

Remember compression is about raising the volume of the quiet parts of the audio not crushing the loudest parts.

lots of compression in small amounts often works well, try different compressors on the same signal but only use little bits.

also do some research on the 'New York' method of compression (i.e parallel bus compression)

[Jay Pace]

Cheers for that barry


Remember compression is about raising the volume of the quiet parts of the audio not crushing the loudest parts.

But isn't raising the volume of the quiet parts achieved through squashing the loud parts and then raising the overall volume?

I don't really understand compression much beyond that. Have I misunderstood?

[rhythmtech]

also do some research on the 'New York' method of compression (i.e parallel bus compression)

works beautifully on percussion with the comp on the aux set to squash the fuk outta the signal and raised just under the original.

[BloodStar]

yeah New York style compression works pretty well.

place compressor as Send effect instead of Insert, then you can add compression just with turning Return FX knob up, and it behaves similar as Dry/Wet knob

you can make some interesting things with several compressors placed on Send effects. just define a role for each (1 for punchyness, 1 for subtle compression, 1 for hot compression, etc) and then twist all 3 Return knobs as you like.. simple.

[Jay Pace]

Rob Acid was saying stuff about that in his mastering video

Cool tips guys, will check em out.

[TechMouse]

How do you change the amount of compression? I thought once it hits a certain threshold the signal is compressed. How does ratio vary the amount of compression?
Put simply, the ratio determines the attenuation over the threshold.

If you have a threshold of x and a signal of y (i.e. y - x over the threshold) and the ratio is 1:5 then it will be attenuated to x + (y - x)/3. Does that make sense?

Basically, the higher your ratio the more squashing goes on.

Check this (http://en.wikipedia.org/wiki/Image:Compression_ratio.svg) if you need to visualise it.

[TechMouse]

But isn't raising the volume of the quiet parts achieved through squashing the loud parts and then raising the overall volume?
Yep, you squish the loud bits of the signal and then raise the noise floor.

[RDR]

Yep, you squish the loud bits of the signal and then raise the noise floor.

yeah, true enough but in terms of dynamics its WAY better to think about it in terms of the loud signals remaining the same as the gain stage of the process is meant to bring back the loud parts to their original stage.