Power my passive subwoofer?

How can I power a passive subwoofer?

• I have a perfectly good passive subwoofer in my current living room surround system. I got a new receiver for Xmas and I now see that the output does not provide power to the sub... ...show more

• Answer:

  Aside from getting an amplifier to power the subwoofer. You could buy a plate amplifier made for specifically for subwoofers, used by hobbyists in the DIY market. The benefit of the plate amps is that they are mono, have all the line level (rca) and speaker inputs, an electronic crossover (most with variable settings) and are not to expensive. It would require some cabinet mods or just make a case for the plate amp. I would suggest leaving the original cabinet alone and building a "box" to mount the plate amp into, even if it's ugly you can hide the amp/box out of site and still enjoy your sub. You can find cheaper powered subs than the plate amps, but I don't know what kind of sub you currently have. Few links below: Edit #3 (sorry): As far as hooking it up to the new receiver you could wire the sub in with the center channel speaker. I say center instead of the front mains because with modern surround sound so much of the signal goes to the center channel, while the mains merely get "surround" signals. One problem with what I'm about to describe is that if you listen to music in stereo (without the surround channels active) the sub won't receive a signal. Also the sub wired with the center channel may be too taxing for the receiver to handle, possibly over heating the amp and causing it to shut down (or even damage permanently). There are two ways to wire multiple speakers together: Series & Parallel Wiring in series will half the impedance the amplifier "sees" where as wiring in parallel does the opposite, it doubles the impedance. For example two 8 Ohm speakers wired in series will become "one" 4 Ohm speaker as far as the amp is concerned. Or 16 Ohms in parallel. What this does to the amp (most of the time) is increase the output power for series and half the power for parallel (a generalization - but close enough to get my point across). Most receivers are designed to handle 8 ohm speakers. In fact the RMS ratings provided by the manufactures is for an 8 Ohm load. Many can handle 4 Ohms as well, check your manuals specifications section (you may see power output listings for both impedance loads). I'm going to focus on wiring in series. All it is, really, is "daisy chaining" You would take the positive (+) lead from receivers center channel and run it to the (+) input on the center channel speaker. Now using another speaker cable, connect the (+) lead to the (+) input of the center channel and run it to the (+) input on your passive sub. Do the same with the negative (-) side of things. Receiver - center channel - subwoofer. You could also run TWO speaker cables from the same output on your receiver, one the the center channel and one to the subwoofer. Again there will be no signal to the sub unless the center channel is being used in the aforementioned set up. All said, I would invest in a plate amp or new powered sub. Hope that helps and good luck!