Hi Ben,

Welcome to Yamaha Synth!
The VCM COMPRESSOR 376 is a very powerful tool. And compressors should be felt, not heard. By the time you are feeling that the sound is "getting crushed" you need to make adjustments.

The so-called "Preset" are starting points, and should never be used simply as is. Adjustments have to be made - because YOUR input signal is the unknown (and changes per song). It would be unlikely that a preset that has a variable INPUT setting, would come set precisely at the right amount for your particular mix of instruments. The programmer adjusted the INPUT and OUTPUT according to their own reference music. You must make the proper adjustments, first to the INPUT amount, then adjust the OUTPUT to the ear level you like.

But the INPUT setting is your first critical setting. In this physical model, the INPUT also determines the "Threshold" or point at which compression begins. In general you want to reduce the energy that gets lost to transient peaks. With the METER set GR (Gain Reduction) you want to set about -1dB to about -2dB of deflection.

In your description above, you are not really clear on exactly where you are applying the VCM COMPRESSOR 376... It can be assigned as a Part's Insertion Effect, and/or as a Mixing's Master Effect. How are you using it?

Preset is a suggestion. The Input and Output need to be adjusted for YOUR source material.
If you can describe the sound as "getting crushed" that would be a clear indication you have too much INPUT, too much Gain Reduction, is taking place... Reduce the INPUT, yes it gets softer, you use the OUTPUT to return the overall signal to "unity gain" - this is a fancy way of saying: you use the INPUT setting to get a small amount of overall Gain Reduction. Not too much, just so the sound fattens up a bit. The OUTPUT is adjusted so that the overall result can be heard.

Input setting = critical, scientific
Output setting = subjective, to taste

Compressors can tend to squeeze the dynamic range, - easy with this - one or two dB is huge.
The only difference between a compressor and a limiter is a matter of degree. Ratios of 2:1, 4:1 and 8:1 are considered compression. When you get to 10:1 and 20:1 that's limiting.

The Ratio, says at 2:1, for every 2dB the signal would go above the threshold, the compressor would allow just 1dB out.
Signal below the threshold is unaffected, but if the signal has enough energy and would pass that threshold by 2dB, the Gain would be Reduced 1dB.

So when the METER is set GR, it deflects downward from 0, indicating the amount of compression.
At 10:1 a signal would have to want to go smashing past the threshold to +10, for the signal to get that 1dB output. Once the signal reaches the threshold, with limiting ratios in affect, the signal virtual gets no louder. It gets "crushed".

Hi Bad Mister,

Great advice as usual. I am using the VCM compressor as a master effect in song /pattern Mode. The main problem I am encountering is that when I combine two sounds, say a string pad and horn lead, one sound, typically the pad, which is not generally the louder one, gets buried too far beneath the lead sound. While your advice is great for a specific patch with set instrumentation, a lot of times I am mixing different sounds on the fly live, so figuring out a general setting for pad and lead would be very helpful. Does compression effect a thicker sound differently , for example a pad playing a chord, than a mono lead? Or does it matter which sound is playing first when the compression kicks in?

Thanks,
Ben

When making adjustments on-the-fly, you must be prepared to adjust everything that needs to be adjusted. The problem with introducing a wildcard (a Voice you have not pre-auditioned) could spell disaster. While in general, a compressor can and is the proper tool to use to keep things on an even keel where volume is concerned, there can be no absolute guarantee that every Voice you select will come in perfectly and automatically balanced.

The compressor works strictly based on the level of the signal. It compresses signals that exceed the "threshold", if the signal does not exceed the threshold it is not affected. Softer sounds will appear louder because they are not "turned down" by the compressor. This subjective response is a human thing. The compressor is simply reacting to level. The human "expectation" or "anticipation" of volume factors in.

Here's what I mean... A singer whispers and then shouts. The threshold is set so the shout is reduced from what it normally would do. We have an expectation that the whisper should be soft and the shout should be loud... The compressor allows us to turn up the overall signal so that the whisper is now louder (closer to the level of the shout), but the shout is no longer that much louder - it get "turned down" from what level it would normally have traveled to...

Over-compression is when we begin to feel like the shout is equal to or is now less loud than the whisper. That is going to be a subjective (human) call. It, in fact, may not yet even be the case - but there is a point where you become aware of the compressor - (this is when you know you have too much!) You have an expectation of relative volumes. If I were to hit a crash cymbal with a stick... No matter how loud or soft I playback that audio recording, your ear/brain has an expectation of volume based on the violence of the stick strike. In other words, you "know" whether the cymbal was tapped or bashed, and expect a certain result - independent of meter readings.

If that shout sounds like it is softer than the whisper - we laugh because we know that's not right. The compressor can't make that call, it's a human thing. It's our expectation, or anticipation that whispers are soft, and shouts should be louder by a lot. If they are too close this equals over-compression.

The best a compressor can do in an "on-the-fly" situation is keep a lid on the overall master volume, the balancing of the two sounds will need to be done, by you, as you perform. You need to setup so you can individually control the volume of each PART.

One key is to have more power than you need, so you have plenty of room to move up or down. Too many musicians work so very close to the ceiling that they get squashed by the limit. The trick is to have plenty of power in reserve so that turning things up and down does not squeeze you in.