Any software for measuring dynamic response of compressors?

[rafafredd]

Is there any software that would automatically make graphics of  a compressor response?

Like a "dynamic sweep" of a compressor response, where one could clearly read threshold, knee, ratio, etc...

A simple X axis straight line input vs Y axis compressed output level.

Seems that it would also need some kind of dynamic sweep speed control to work with slow and fast attack compressors.

Is there ANYTHING like that???

 

[Bo Deadly]

Not really. You just have to put a stimulus like a 1kHz tone into the input at stepped levels in 1-2 db increments and then record output level with compression out and output level with compression in. Ideally the compressor has a switch that just switches off compression without adjusting levels or anything else so that you can record the "with compression" and "without compression" measurements at the same time thereby isolating just the effect of compression. Then punch the numbers into Excel in three columns for input level, output level without compression and output level with compression and make a scatter plot. The lines of the plot should overlap until the input level reaches the point where compression kicks in and then the with compression line bends over. Then you have your typical compression knee plot where you can see the character of the knee and at what level it kicks in.

There is another way that is quick and dirty but ok in some instances. Some software has a stepped THD measurement where it incrementally increases level and outputs THD numbers. Some compressors are known to have a particular THD profile at different levels of compression. Meaning how the THD go up as compression kicks with at different ratios is a sort of signature. The 1176 is a good example of this. This won't give you a knee plot but it can be used to quickly validate the device is working at least in a comparable way.

 

[rafafredd]

Thanks, man. really appreciate your input.

I actually know quite well how to do it manually, amd that´s why I wanted an automated tool I could use to test many different compressors in many different settings, software and hardware, get easy compression signature curves and compare.

Doing it manually will take loooooong hours...

 

[guze]

plugin doctor from ddmf let's you use external signal

 

[RuudNL]

The easiest way is probably to use a DAW.
Create one track with a level stepped audio signal (1KHz or what you like), play that track trough the compressor and record the result on another track.
Usually you can zoom in far enough to see milliseconds and this way you have an indication of the attack and release times. (Anyway: that is how I do it...)

 

[Bo Deadly]

Create one track with a level stepped audio signal (1KHz or what you like), play that track trough the compressor and record the result on another track.

Good idea. Play that stimulus tract with compression out and record a control track. Then play it again with compression in and record another track. Then export that into a stereo 32bit float wav file with the control track on the L channel and the compression track on the R channel. Then run that through a GNU Octave script to plot the knee. Requires a little code but that how I'd do it.