Hi Brian:
Good question. I think I understand it, but if not maybe this will at least be entertaining. :) I’m leaving out important lesser points - but here’s my pitch...
My goal is to eliminate the expense, etc., involved with using a hardware loudspeaker processor between MC and the amplifier(s). The huge advantage of an external processor with crossover and EQ filters is that I can send the output of my measurement device instead of music through the processor - amplifier - loudspeaker to see the real affect its electrical filter adjustments have on the raw driver passband.
It is the combination (you could say convolution) of these electrical filters and the raw driver response that yield the actual acoustic response at the measurement microphone or your ear. It’s that combined acoustic response that we’re ultimately trying to massage into as close a copy as possible with the electrical output of our prerecorded music playback system, generally speaking. A classic way of doing this that was more interesting than useful was to playback low level 100Hz and 1kHz square waves and see how badly the loudspeaker system mangled it in the acoustic domain.
If loudspeaker drivers had perfectly flat frequency responses with instantaneous time domain tracking of the electrical signal, then we could ignore the raw driver’s contribution to the mix and just implement filtering in MC and know that’s what we’d end up with getting to our ears. Not gonna happen in this universe, unfortunately. :)
Bottom LineVery few MC users will ever have the knowledge, money and time to properly tune a loudspeaker system, especially a multi-way system, without closed-loop measurements. Open looped measurements leave out the critical phase information, without which it is impossible to align a crossover (among other things).
DefinitionsClosed-loop means connecting the output of your measurement system to the system under test (MC - amplifier - loudspeaker) with the measurement microphone feeding the input of the measurement system.
Open-looped means you generate a test stimulus file, import it into MC, then play it back and record the acoustic result with your measurement system. The measurement system loses track of time, thus phase, with this method.
ConclusionThere’s a reason why the windows version of MC has the ability to accept closed loop measurement connections and the Mac version needs it for the same reason. There is no practical way at this time to use MC for Mac to replace an external loudspeaker processor for bi-amped, tri-amped, etc., setups. :(
BackgroundHigh Frequency Crossover AlignmentSubwoofer Crossover Alignment