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I have a simple Bluetooth speaker that always seem to cut off its speaker circuit when the audio stream goes silent. This makes an audible popping noise, which is repeated when the stream starts delivering actual sound again. As long as there's sound playing continuously it works ok.

The problem is that the speakers are always activated too late, resulting in skipping the first syllable of a sentence in an audio book or in a video with silent parts.

Another problem is that it also happens whenever the volume is very low at the source, which means I don't get to listen to the actual audio, just a lot of popping noises.

The IC responsible for driving the speakers seems to be M6008N. My question is if it's possible to make it stop cutting off the speakers just because the stream is silent?

Details

  • The problem only occurs when playing from a digital source, i.e. Bluetooth and not through line in.
  • It only occurs when played through its built-in speakers, i.e. not using its line out port.

I could only find data sheets in chinese of the IC.

Example schematic

Am I even looking at the right thing?

The only other thing of interest is a tiny premade bluetooth module board which I can't do much with. It seems to take care of storing the sound effects and handling the mandatory worthless microphone, but I can't say if that raises the probability of the problem being located on it.

My level: beginner

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  • \$\begingroup\$ You could try mixing in a sub-sonic (10 Hz or so) pure sinewave into one of the channels to keep it awake. Set the amplitude to the minimum level that works as the audio signal will be riding on top of it and the peak signal level will be reduced by the amplitude of the sub-sonic signal. \$\endgroup\$ – Transistor Nov 6 at 21:17
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    \$\begingroup\$ If this is a $2 amp you got from aliexpress... if I were you i'd wonder if it is worth it spending a few hours of your time polishing this particular turd, when you can get a much better turd from aliexpress for $3 :D \$\endgroup\$ – peufeu Nov 6 at 21:43
  • \$\begingroup\$ Get a scope (or maybe at the outside a voltmeter) and probe the inputs. See if it's the bluetooth chip dropping the output, or somehow commanding the amp to mute/shutdown. The likelihood of achieving your goal is fairly low. \$\endgroup\$ – Chris Stratton Nov 7 at 1:36
  • \$\begingroup\$ @Transistor Thanks for the suggestion! \$\endgroup\$ – Andreas Nov 8 at 17:30
  • \$\begingroup\$ @peufeu It's more like a $15 speaker, but I suppose I am a hopeless acceptor of challenges. Most people advise me to throw money at problems, but I can't help but go "this looks interesting" a lot of the time. If I screw something up I would prefer it to be a cheap mistake. \$\endgroup\$ – Andreas Nov 8 at 17:40

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