Nigel Goodwin said:
Assuming the output is bridged, which gives a differential type signal, either wire contains the complete information, one is just the inverted version of the other. To feed to a further amplifier you only need to use one of the output pins.
Considering there are hundreds of amplified computer speakers about, at very low costs, why not just use one of those? - if required take the insides out and build it in a smaller case.
Nigel,
When you say bridged, do you mean the two (-) lines are tied together somewhere? If I can use either L- or R-, can I physically tie these together (L+ and R+ would then be for each channel with a common -)?
Let me make sure I understand this correctly...
For my SBC outputs, I would use 4 resistors (two per channel) to make my voltage dividers. Both would reference the same (-) signal, either left- or right-. This will be the input to the amplifier.
Then, on the output of the amplifier, I can use one of the (-) lines, either Lout- or Rout-, for both speakers (to allow me to use a 3-pin connector).
I can't use off-the-shelf amplified speakers and repackage them because (1) they need to be waterproof, (2) the amplifier and speakers need to be rated for -20C to +70C, and (3), all my interface and support circuitry will be crammed onto one PCB--digital I/O interface, analog inputs, alarms, USB hub, power distribution and E-stop, and last but not least among other things, the speaker amplifier.
Thanks,
Dale