compression type differences

[skuthepoo]

not sure if this is the right area for this post, but anyway:

i can hear the difference between the different compressions, but can someone explain a little about each one and its traits and what its used for generally, etc? cause i feel i need to know a bit more about what each compressor type is doing to my signal

like VCA, opto, etc.

thanks

 

[bassman1441]

A VCA works by varying the voltage of the audio signal when the audio signal reaches the threshold, hence the name Voltage Control Amplifier. This is done with solid state components.

Basically an opto comp, or optical compressor, works by using a light source which varies with the voltage of the audio signal, and an optical sensor that detects the light which in the end causes the gain reduction.

Anyone else feel free to add a more detailed description

 

[tmix]

I am not sure if I am going to adequately answer you where you understand but here goes.(laymans understanding)

VCA type (voltage controlled amplified) measures the amplitude of the incoming waveform (ever seen an ocilliscope?) and translates the the higher the amplitude into a rising voltage. dependant on your settings as to where the threshold etc is is decreases the volume (reverse amplification) dependant on what it translates the incoming voltage to be.

Pros:
Very fast, reacts quickly good for fast transients and things without a lot of heavy bass content.

Cons:
reacts too quick sometimes on low frequencies making a distortion of sorts as it tries to ride the voltage sweep of the huge bass waveforms.


Optical compressors. Literally uses the translation of the incoming signal to voltage to light up a small light inside the unit, with a receiver that converts the light brightness to a deamplification. This type is a bit slower to react but sees the total picture better rather than reacting to every different waveform.

Some feel this is a more musical form of compression and it certainly worked better on bass guitar and the like. it is slower on some types of high transient stuff.

 

[skuthepoo]

Thanks guys