the line/mod switch is just an attenuation.
I double checked this in the code , we can see it here:
//-16.2dB attenuation in line mode
if(getState<OutputLevelSwitch>() == Toggle2posHoriz::State_t::RIGHT) {
outputLeft *= 0.155f;
outputRight *= 0.155f;
}
its just to ‘notionally’ get it to line level, vs modular level - doesn’t mean much in a software environment tbh.
also the module does not do any gating as such…
however, two things could be occurring
a) DC offset
as its designed as an output module, its has a DC blocker. which means any DC offset will be removed (by a filter) from the signal, this can naturally attenuate a signal - the more the offset, the more the attenuation – this possibly might be what you are hearing?!
DC offsets are pretty common in modular, esp in digital modules - you can use an offset on the signal if necessary.
b) noise gating on Octatrack?
have you got the noise gate set on audio input on the OT?
using the ‘attenuated’ signal would make this ‘worst’, as generally you have a quieter signal - so S/N ratio is worst.
what you can try is:
a) Use a Scope
you can use a scope on the MM to look at the signal, in particular.
do you see the ‘gating’ in the signal, if not, then its happening somewhere in your hardware setup.
do you see an offset? if so you can try to compensate for the offset.
b) don’t use mod/line switch
as above, there is really no need in a software environment.
instead what I do is have a gain/attenuator module ( * ) on the MM at the end of the chain.
you can then use this for gain staging, to try to get the signal as ‘hot’ as possible without saturation. you want higher S/N ratio.
( * ) actually, in my main setup, I use a hardware output module, so I do it there instead.
mainly, because, it has a headphone jack, and separate controls for main out and headphone out.
c) turn the noise gate off (reduce its level) on the OT
actually this is not necessary if you have gain staging correctly done in (b), unless your signal has a lot of dynamics.
I have my gate set very low (often off) on OT, as I use expressive (mpe) controllers, and find the gate on the OT way too harsh/abrupt.
but its a compromise, as I find eurorack inevitably adds some noise, so its a necessary evil/compromise.