Aggregated device sound issues

[omerweiss]

I am using Soundflower and a focusrite physical interface within a single aggregated device (Mac OSX)
during usage i am facing timbral changes (sounds like a low pass filter switches on and off)
I suspect that the reason for this is the fact SF is locked on 32 bits while my other device is locked on 24 bits.

is there a way to change bit depth in SF?
i know it was possible in the past, but now it's not possible in "audio MIDI setup".

thanks.