I've had friends complain for some time that my microphone crackles and pops over voice calls. With the help of Helvum and alsamixer, I did a bit of troubleshooting yesterday and found that the gain is just too high - that's what seems to be causing the crackles. I had it set all the way up to 30dB, because otherwise my friends couldn't hear me on calls. With 0dB of gain in alsamixer there are no crackles whatsoever, but nobody can hear me.

I'm using a Sennheiser PC38X headset hooked up to a Mayflower ARC Mk2 USB DAC/AMP. I'd be happy to share software info as well - just let me know what commands to run. From memory, I'm using pipewire with wireplumber. No customized config or anything.

I'm looking for some way to amplify my microphone enough that my voice can be heard, while avoiding the crackles and pops.

  • Case closed! Unfortunately it seems my DAC/amp has developed a case of crackly microphone. I tested the headset & DAC together with another PC. The mic crackled there too, so I just had to do a bit more checking to make sure it wasn't the cable. I've contacted the manufacturer in the hope that they'll do something to help. If they don't give me any good options, maybe I'll try and fix the faulty hardware myself. We'll see 🤷‍♂️

    Thanks all for your input!

This kind of setup uses an electret microphone which is very compact but also very prone to failure, especially if exposed to small amounts of moisture. To save a lot of wasted time with computer diagnostics, is it possible to try your headphones and boom mic elsewhere to prove that it is not the culprit?

    BuzzPCSOS The same headset works crackle-free on my laptop (EndeavorOS). A few notes on the configuration there:

    • Used a different cable between the headset and device (4-pole TRRS rather than the split headphone/mic TRS Y-cable)
    • Used the laptop's integrated sound card rather than the Mayflower DAC/amp
    • Gain was still set to 30dB using alsamixer

    After piping the mic to the headphones using Helvum, audio came through loud and clear. So I think we can eliminate damage to the headset mic as the root cause here. Thanks for the suggestion.

        infinitymdm All electret microphones take a voltage on them to work hence the name
        so if this voltage is low or incorrect they dont work properly.

        I was watching a youtube video with your headphones and dac/amp and the mic sound the guy had was not
        impressive (weak and noisy) have you used the headphone dac/amp setup before on anything else with
        success.

        They are wired with a cap resistor setup the cap blocks the voltage from equipment but makes the difference on audio quality ,the resistor feeds the op voltage to mic.

        Under voltage makes mic sound clear but weak and overvoltage sends stuff into saturation making noise
        and weak audio.
        This is more along the lines of analog stuff throw in digital proc and it gets complicated.
        My guess the laptop setup is more matched properly is why it works.
        I use to and have wired tons of communications headsets up to stuff.

        Zmaint was right to ask his question electret microphones are not hardy animals they tend to fail
        easily.

        Am done rambling.

            Axios I believe I had things working (i.e. no pops) with this headset/DAC combo with my previous desktop. I'll give that a try once I get home today and report back.

                infinitymdm Ahh just some info on how things work sometimes makes diff in getting things working

                  Axios They are wired with a cap resistor setup the cap blocks the voltage from equipment but makes the difference on audio quality ,the resistor feeds the op voltage to mic.

                  Under voltage makes mic sound clear but weak and overvoltage sends stuff into saturation making noise
                  and weak audio.
                  This is more along the lines of analog stuff throw in digital proc and it gets complicated.

                  You're talking about an RC filter? I'm an electrical engineer by trade; don't be afraid to go into technical stuff. I can break out a breadboard if I need to.

                  As for the digital stuff, my roommate does research in ADCs, so we talk a lot about sampling 😄

                      Case closed! Unfortunately it seems my DAC/amp has developed a case of crackly microphone. I tested the headset & DAC together with another PC. The mic crackled there too, so I just had to do a bit more checking to make sure it wasn't the cable. I've contacted the manufacturer in the hope that they'll do something to help. If they don't give me any good options, maybe I'll try and fix the faulty hardware myself. We'll see 🤷‍♂️

                      Thanks all for your input!

                      Process of elimination your troubleshooting friend.
                      I tried to find a schematic on that or for any of those crazy things Havent found any at all.
                      Will keep searching when bored..lol

                      So I worked with the manufacturer and did a bit of troubleshooting. Turns out the ultimate culprit was moderately faulty grounding in most of my PC's USB ports. This isn't an issue for most things, but since the DAC takes its ground from the USB connection, it was causing all sorts of electrical noise to couple into the microphone analog input.

                        infinitymdm Interesting I kinda gave that a thought but passed it off sorry.
                        Didnt think it would be an issue since getting power from usb.
                        But glad you figured it out the end result counts.

                        Just a tidbit I use to make alot cables for stuff on the shield I always left disconnected at one end.