I'm designing a small PA system. I currently have the following setup (stereo main mix into 2-channel amp with 4 speakers [front and rear in parallel]):
+------+ +---+ +------+
|LF-Spk|<------L--+|Amp|+--R------>|RF-Spk|
+------+ +---+ +------+
+ ^ ^ +
| | | |
| | | |
| L R |
v + + v
+------+ +--------+ +------+
|LR-Spk| |Main Mix| |RR-Spk|
+------+ +--------+ +------+
The problem I am encountering is that this setup does not allow me to adjust the volume of each speaker independently. I can adjust the volume of the left and right on the mixer, but I would like to adjust the volume of each speaker independently. There is no apparent way to do this while my speakers are in parallel.
My current plan is to get an additional 2-channel amp for my rear speakers and set up my system like this:
+------+ +----+ +------+
|LF-Spk|<----LF----+|Amp1|+----RF----->|RF-Spk|
+------+ +----+ +------+
^ ^
| |
+--+ +--+
| |
+------+ | +----+ | +------+
|LR-Spk|<----LR----+|Amp2|+----RR----->|RR-Spk|
+------+ | +----+ | +------+
| ^ ^ |
| | | |
L L R R
F R R F
+ + + +
+------------+
| Main Mix |
+------------+
The problem is that my mixer only has a 2 channels out (L and R). I would prefer to not buy a new mixer. In fact, I sort of need the opposite of a mixer: something that takes two channels in and adjusts its volume for multiple output channels. Are there products that do this? Or is there a better way to tackle this problem entirely?