Audio/electronic challenge

Here’s a challenge for the audio/electronic types: can I combine right- and left-channel signals to drive a single-coil subwoofer without creating a mono signal in the right and left channels?

You can split your left and right outputs. Send one left-right pair to the corresponding left-right speakers. Recombine the other left-right pair with another Y-connector and send it to the subwoofer.

That doesn’t sound right to me. Unless the splitter and/or Y connector has diodes or amps to isolate the signals, the Y connector will connect the two outputs. The left/right speakers will get the same signal.

emolson, are you asking how to do it using off-the-shelf audio equipment, or what kind of circuit is required? If it’s the latter then all you need is a summing amplifier. If it’s the former then I don’t know, sorry.

If you’re coming from the pre-amp section, I think it would be safe to connect a Y cable to a separate output section, like a tape out. That shouldn’t affect the main outputs.

If you can only hook up to the final output, I think you’re out of luck. You could hook up the subwoofer to just one side. Low frequency sounds are usually centered in the mix, so you wouldn’t miss that much. The bad part is, you would be putting an additional load on one side of your amp.

The best thing to do would be to buy an active crossover that accepts two inputs. That would also keep the subwoofer frequencies from being sent to the regular speakers and make the whole system sound clearer. But then you’d also need a separate amplifier for the subwoofer.

I believe there are amps for subwoofers that have the crossover circuitry built-in.

Some subs have jacks where you hook the sub to the line out mains and run the (tweeter/mid) speakers off the output jacks on the sub. The sub combines the left and right into mono signal (for itself) and passes on the discrete signals to the output jacks.
Brands to check out: Velodyne, Vandersteen, JBL.

First, I will assume that this is for a car installation, since you know it is a single voice coil sub.

Is the amp bridgeable? If it is, the problem is simple, take the bridging outputs from each channel to the sub and you are done.

Really, we need more info on the equipment and what you are doing to answer well.

Data needed:

  1. Where is this being installed.
  2. Type/size of sub
  3. Type/size/bridging capable? amp
  4. Trying to drive other speakers with amp at same time? (what kind, how many?)
  5. Are there other amps in the system that might be pressed into service?
  6. What is your budget, there may be ideas that would really improve the situation by adding some stuff.