amplitude dependant theory

[markphaser]

Why is a FET compressor,Optical Compressor, VCA compressors all have different amplitude dependant curves? the thresholds times, attack times,release times are all different why is that? its sens dynamics levels making it amplitude dependant but they trigger the compression circuit different why is that?

Some compressors have "sustain parameter" is this a feedback output circuit?

[markphaser]

I hooks up a function generator to the compressor and then to a oscilloscope i moved the frequency range up and down nothing at all happens if i move the function generators volume output then the compressor amplitude depandant curves i see on the oscilloscope
the attach times,release times but it happens really fast its not steady

[petemoore]

   comps sens input voltage e
  *whatever is coming in, loud or small, goes to the signal path section, usually containing some type of controllable boost
  Whatevrs' coming in also travels at the same time to the sensing unit, this sends a message to the boosting section, telling it to turn down the volume while input voltage is high, like when you strike a low note hard or wham out a chord.
  Something changes when input voltage is high, whether it be a rise in voltage to an LED/driving an LDR,  or whether any other method is used, input goes up>level goes down, instantly is nice, 'how' the compressor responds...fast on attack, slow on release or any other ratio's, is why some prefer one comp over another, and why a more adjustable comp may be more useful to one person than a simple one would be to another.
  LDR's have a 'built in sag' in that it takes 'some' time for the resistance to change in response to changes in light amount  recieved.

[markphaser]

LDR's have a 'built in sag' in that it takes 'some' time for the resistance to change in response to changes in light amount  recieved

Yea the "Sag" changes the linear line attack voltage curve

The sensing circuit a envelope follower

The Envelope follower has attack time,decay time ,release time that controlling the gain/preamp section

In a FET compressor or VCA compressor what can create a "Sag" effect on the attack time sag, decay time sag, release time sag?

[petemoore]

  I can think so far about the OS Comp. being Jfet controlled, search mods for OS comp., IIRc there is good info about how to 'bend' the circuit to make it exhibit different ramp up/down characteristics.

[markphaser]

Yea most compressors don't like u change the Ramp up or down times or velocity curves its mostly just fixed right?

Every compressor has a envelope follower which is the sensing circuit but the ramp up and down times are fixed not variable