compression ratio in compressor function:

hallo all,

Is there a way that one could interpret the compression ratio in the compressor.

it value varies from 1 to 50,

From the MATLAB page: the compression ratio is defined as R=(x[n]−T)(y[n]−T).

But: in the example:

drc = compressor(-15,5);

visualize(drc);

https://de.mathworks.com/help/audio/examples/multiband-dynamic-range-compression.html

%How can we recaluculate (to know) what was the compression ratio from the graph?

Is the compreesion ratio (standard) the slope i.e the dofference between Inputs/Outputs??

can one give an example?

thanks a lot

Answer 1

[Charlie DeVane]

Hi Khaled,

Looking at the static characteristic (input/output graph), the ratio R is the reciprocal of the slope above the threshold. (Below the threshold the slope is 1.) In the doc example, above threshold the output increases 3 dB for a 15 dB increase in input, so the slope is 3/15 = 0.2. The ratio is the reciprocal of that: 15/3 = 5.

In the doc for compressor you can find the equation for the static characteristic above threshold, where you can see that the slope is 1/R:

hth,

Charlie

[khaled hassan]

Thanks Charlie!!

do you know if there is a way to have several knee points: thresholds for one compresso rin MATLAB?

best wishes,

Khaled