this file is your stereo file? t-b&k linear phase f-default (true time domain) m-2.2 bis 10 janv 2017 - 480002.0_441.cfg
it uses channels 1,2,3,4,7,8 of the wav file where 2 & 4 are clearly the tweeter
the cfg file routes as follows (named MC channel -> wav file channel -> named MC channel)
L -> 1 -> L
L -> 2 -> C9
R -> 3 -> R
R -> 4 -> C10
L -> 7 -> SW
R -> 8 -> C12
the tweeter channels have ~9-10dB of headroom so if you add 25dB to them then if you either don't use internal volume or your internal volume goes beyond ~-15dB then you're into clipping if playing a full scale signal
80% is -10dB and most content is mastered such that true peak is close to or beyond full scale so that implies you're riding the limiter (aka compressing) because you're going beyond full scale digitally
if you then have the motu at -10 then your signal chain is basically
* convolve (which cuts somewhat)
* large gain into clipping
* hit the MC limiter (hence compressing)
* attentuate in the motu driver
* to the DAC/amps
i.e. down up compress attenuate
it's a gain structure problem basically
the fix to this is
* scale up all channels in the wav by ~9.5dB
* remove the PEQ gain block
* remove the cuts from the motu
* set the MC internal volume limit if necessary to prevent clipping the amps (if you say what they are then we can calculate that also)
separate to this, it's still not at all obvious where your actual problem lies in MC33
there is a link here -
https://wiki.jriver.com/index.php/Verifying_DSP_Studio - which explains how to measure this stuff yourself which would show objectively where the problem lies. If you don't feel confident in doing that then export your dsp config to a file (i.e. dsp studio -> presets -> save to file) and post that file here *with DSP studio configured in a way that has the audible problems*