Maybe it’s staring me right in the face, but changing the number of filters beyond 4 under the EQ window doesn’t appear to have any effect?
I can duplicate the issue on macOS 11.2.3. What macOS version are you running?
This is an odd problem because I am almost certain I remember the UI working correctly before.
I’m also on 11.2.3 (running on an M1 Mini).
I’ve looked into this problem further. Internally the equalizer is an AVAudioUnitEQ object and it seems that the number of bands that the equalizer is created with becomes the maximum number of bands it supports. This behavior is not documented for AVAudioUnitEQ. I initially create the equalizer with 4 bands which is why the limit appears to be 4.
I’m unsure whether this is a bug in the Apple-provided equalizer user interface, meaning that the number of bands above 4 shouldn’t be shown or selectable, or in AVAudioUnitEQ itself.
I can work around the problem by creating the equalizer with either 0 or -1 bands which allows 1-16 bands to be selected.
The fix will be in the next version.