Hiya
It looks cool.
I use something simular passive etc and very cheap from Pro Audio (Australian company).
I wonder why did you add a stepped output level knob??
Shouldn't the calibration apply to the level of the final file/mix etc?
The volumes of mixes that shall be mastered are mostly at different levels.
Is it necesarry to know the exact output level of the control room monitoring system during a session?
I turn up and down the control room monitor level a lot of times during a session. To adapt it to speaking level (talking with customer) etc and to adapt it to different speaker pairs.
Best wishes
