I have a laptop I swapped in with an existing desk setup that includes

  • a mixer for the audio from several computers
  • an amplifier that I use to split the microphone from my headset between all the computers

The newer laptop appears to support this: https://source.android.com/docs/core/interaction/accessories/headset/plug-headset-spec#control-function_mapping

Unfortunately when the microphone path is connected, the volume on the newer laptop repeatedly drops, but when I disconnect the microphone path things work as expected (except the microphone).

I believe the newer laptop is interpreting the impedance of the amplifier from the microphone path as a depressed volume down button.

I am working around the problem by using a USB audio device for now, but it looks like I need to change the impedance from line level to mic level. It looks like a potentiometer should be good enough for what I need and I see some options available built into a cable.

Does this sound right?

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  • \$\begingroup\$ If your PC has a headset port, it expects to see a mic impedances and voltages, or then it's not a headset or it interprets the impedances and voltages wrong. You never said what kind of amplifier you have or how you connected it in place of a mic, so if it does not simulate a mic then it won't work. \$\endgroup\$
    – Justme
    Commented Jul 10 at 23:08