TOPIC:

Does bypassing filters that are not in use reduce noise in the system compared to leaving them in the default flat state?

Not sure if i understand your question... No relationship between noise and filters.
If a filter isn't in use, then bypassing should be toggled rather than trying to put the filter at the extremes. There aren't many options here:

Filter is either in use (at a specific cut off frequency)

or not (then in Bypass mode.)

Hope this makes sense.

What I mean is that the rounding errors in the arithmetic of a filter create noise, so that if you put a whole load of filters in series the rounding errors accumulate. I was asking if those errors accumulate on the filters set to default.

Dirk,

I believe that I understand what you're referring to... Are you talking about all the PEQ filters set to e.g. 20 for each band even when not in use? (term filter being a bit wide knowing that you have LPF/HPF/PEQ...)

FYI, if boost is set to 0 is like having the filter in bypass. Audio passes through without any rounding error..

Does this answer your question?

Yes, thanks.