I'm building a bluetooth speaker, but I'm not satisfacted with the low frequencies, so I decided to add a subwoofer. At the moment I haven't decided which subwoofer exactly, but I'll will be a 4 or 8 Ohm one. Here is a list of my current components:

  • Amp - TDA7492
  • Speakers - Visaton FR 13 (x2)
  • 12V 12Ah Battery

    Even if the sound is not optimal, what's the best way to connect the subwoofer by having only 2 channels? Is there any way to make the subwoofer receive signal from both L and R? I assume my idea is probably wrong, but is it possible to connect them like this? The subwoofer is the bigger box. test Any help is appreciated.

1 Answer 1


You will find that your current solution will mix the output and you will get mono audio at all speakers. You need to insert a lowpass filter into the circuit between the amplifier and the subwoofer.

Make sure you filter both the left and right signals independently prior to mixing the audio for the subwoofer.

Information on lowpass filters can be found at https://www.electronics-tutorials.ws/filter/filter_2.html

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