OMX compressor [omx.comp~] parameters

Chris Rolfe's icon

The OMX compressor seems useful if daunting. Like others though, I'm scratching my head a bit over the lack of parameter units.

1) Attack/release times are 0…150 with 150 being "faster". Any ideas what the fastest time is? [edit: testing suggests fastest 0 is 4 samples].

2) ratio -- the documentation [see patcher below]:

https://docs.cycling74.com/max8/tutorials/17_msp_compress_03

>Ratio uses exponential values. To convert the numbers given to ratio use an expr object with the following arguments: ln($f1) / ln (1.04)

Mapping $f1=0…100 or $f1=0…100/100 gives limiting values, like 87:1 for the vocal preset.

Has anyone got a better idea of OMX parameters?

Chris Rolfe's icon

In case this helps some future Max user, here's a patcher that converts OMX unitless ratio to a standard (3:1, 5:1, etc.) compression ratio using the scale object.

Max Patch
Copy patch and select New From Clipboard in Max.


Ratio: The vocal preset's (OMX_ratio=31), for example, corresponds to a compression ratio of roughly 3.4:1.

Attack: From measurement, the fastest attack setting is 4 samples in length.

Nicolas Kaniak's icon

im still wonderin on the units for attack and release

Roman Thilenius's icon

or for the reason why they are not presenting themselves in ms.