Part one is easy
[quote author="Purusha"]I need 3 stereo balanced inputs:
1.) stereo mix from my Midas mixing board
2.) stereo from my Emu 1820M soundcard (1st PC)
3.) stereo from my Emu 1820M soundcard (2nd PC)[/quote]
a simple Lorlin 3pos x 4 pole will do this
3 balanced stereo inputs to a single balanced output
you can not mix the PC's or Midas
one at a time
if you want to mix it all gets more difficult ... but possible
Then I need 3 stereo outputs for monitors + one extra for subwoofer:
1.) stereo output for my 1031A Genelecs (with extra adjustable volume control in the back)
blah blah
4.) stereo out for my subwoofer (with extra adjustable volume control in the back) - this output should be independent of the previous 3 and should have a separate switch for on/mute so I can use it with any speaker system
number 4
is where things get hard
it means that each output must mix to the one input for the sub
you also need a different volume trim for each satellite pair
OR
you trim the satellite pair to suit the sub
also one of your satellite pairs is self powered and the others are passive
will you use the same amp for the second passive set ?
for a FULL PIC controlled system this is just programming BUT for a simple passive/active it can get very difficult
do you want the subwoofer by itself ?
very very difficult for a simple passive/active system
again this is begging for the PIC controlled system as it is complicated
hard to make a generic system mix passive and active with a single sub
Then the extra features in between:
cover that later
but the more complicated the features get the more likely you can only do it with an integrated programmable system
might feel a little stupid on a multi turn rotary encoder
:grin:
I suggest a simple 3 x 4 switch
then 3 stereo volume + mute circuits
a simple 3 into 1 mixer to feed the sub
... an amp for each passive pair
to do all this passively could have some screwy loading issues
and there will be the possibility to have all 3 channels up at once
the sub being available to each system is what made it difficult