Subwoofer Wiring Diagram

After building your own DIY subwoofer, you're probably wondering how to hook it up to your main entertainment rig. Here's where a subwoofer wiring diagram comes in handy.

First of all, make sure you have got the following things:

  • Dedicated subwoofer amplifier
  • Amplifier for each channel

    Consequently, proper wiring of woofer to amplifier and filter electronics is necessary before you proceed.

  • Remember to test everything before you turn on your subwoofer orelse damages may occur. You've been warned! I recommend doing a test-run simply by turning on the device without actually connecting it to your system.

    If you hear no humming sound, weird noises or smoke (just kidding) coming out of your subwoofer - Congratulations! It's time to connect everything.

    You now have three choices to connect your new subwoofer:

    Parallel Operation

    One of the easiest ways to connect your subwoofer is to connect it in parallel with your main speakers (see Fig. 1)
    Subwoofer Parallel Connection
    Simply take two extra leads of loudspeaker cable coming from your main amplifier speaker output terminals to your subwoofer speaker input terminal. Both left and right audio channels would then be summed up on your subwoofer. Next you should experiment with the crossover frequency - that's the low frequency threshold from which your subwoofer will be working. Try something in the 40 - 60 Hz range.

    Connecting the Subwoofer to Home Theater AV-Amplifiers

    If you own an AV home theater amplifier or receiver, you'll find a dedicated high-level RCA output on the back of your receiver. Most of the times these outputs are labeled SUB OUT or LFE OUT (LFE = Low Frequency Extension) (see Fig. 2)
    Pre Out
    Wire an RCA cable (mono) from that output to the RCA input of your subwoofer amplifier. Because AV-amplifiers usually have quite sophisticated built-in low-pass filters already, you can safely turn off the filter electronics in your subwoofer module. This way your AV-amplifier or receiver will be in charge of the subwoofer configuration.

    You've probably noticed, that a full-blown rear-panel mounted subwoofer module might be obsolute here. Absolutely correct -- your receiver already uses its own lowpass filter, so you can get away by just powering your subwoofer by a dedicated standalone amplifier. Any spare amplifier, a second hand model or PA amplifier will work just fine.

    Connecting the Subwoofer to Stereo Preamplifiers

    Since you might not have dedicated subwoofer outputs, simply buy a subwoofer or "Y-cable" to split the audio RCA preamp outputs. (see Fig. 3)

    Connect an Y-cable to your preamplifier's output. You now havetwo pairs of outputs. One pair goes to your power amplifier that feeds the main speakers. Hook up the second pair to your subwoofer's RCA inputs and you're done.

    To relieve your main fullrange loudspeakers from the tiresome burden of reproducing thunderous low-frequency earthquakes (and if supported by your subwoofer module), you can connect your mainpower amplifier output to the subwoofer module and have it "filter out" low frequencies either completely or to a certain degree. This would result in your main speakers only playing midrange and treble. I don't recommend this in general as it might not produce good results with every speaker but why not give it a shot? Ultimately, it depends on your taste, room acoustics and system synergy.

    Other Subwoofer Related Tips

    How to build your own subwoofer.

    Subwoofer Placement Guide - how to do it correctly.

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