Debugging microphone issues in Linux and Zoom

Posted Almost 4 years ago. Visible to the public.

Testing

Since Zoom does some post-processing of your audio input, it's best to hear yourself in a Zoom recording:

  • Open a Zoom meeting for yourself.
  • Choose "Record to this computer" in the Zoom toolbar.
  • Speak some words (quiet and loud) and allow some seconds of silence.
  • End the meeting.
  • Zoom will open a folder with an audio recording.
  • Listen to the audio recording.

Check microphone settings in Linux

Right-Click on the speaker icon in your tray, then go to Sound Preferences => Input.

Selecting the correct microphone

On a notebook you want to get sound from your microphone jack and not from the internal microphone.

A desktop PC will often have multiple microphone jacks (front microphone, rear microphone).

Make sure the right microphone jack is selected in the Linux input settings.

Choose an audio level

The Linux input settings also have a live meter showing you the volume of your input feed.

Talk into the microphone and watch the meter.

  • When you don't talk, the meter should be zero. If it wobbles while not speaking, you might have a wiring issue (see below).
  • When you talk normally it should be in the lower third or lower half.
  • When talking loudly, the meter should rarely clip the maximum range.

Check microphone settings in Zoom

In the Zoom settings, go to the Audio tab.

Selecting the correct input source

Under Select Mic you should select "Build-In Audio Analog Stereo", or the name of an external soundcard if you're using one.

Choosing an audio level

The Zoom audio settings also have a live meter showing you the volume of your input feed.

Talk into the microphone and watch the meter. The meter should move as described above.

Try unchecking "Automatically adjust volume" and setting an input level manually.

Prefer controlling the input level over the Linux input settings, and not Zoom, so amplifications happens as close to the source as possible. This might mean selecting the lowest possible input level in Zoom.

Again check how the meter moves as you talk into your microphone.

Wiring issues

If you hear cheeping or other electronic noise in your recording, make sure the microphone cable doesn't cross any other cables, especially power cables.

Internal cards on desktop PCs are often cheap components with bad shielding. If problems persist, try using a different microphone jack. This will not help if the internal soundcard uses unshielded wiring inside your desktop tower.

Try an external soundcard (or an USB headset)

If issues persist, try using an external soundcard. We have some USB sound cards that look like USB thumb drives with headset jacks.
You may also try an headset with an USB jack (instead of an analog 3.5 mm jack), which have their own sound card.

An USB sound card should be detected by Linux automatically. After plugging it in you need to select it in:

  • Linux audio input settings
  • Linux audio output settings
  • Zoom audio: Speaker
  • Zoom audio: Microphone

Try Zoom in Chrome Browser

The native Zoom application itself or how it interacts with your setup could be the problem. As a last resort you could use Zoom with your Chrome Browser and test if problems still persist.

Caveat: You won't be able to use all the native Zoom features (e.g. to blur your background).

Henning Koch
Last edit
About 2 years ago
Simon Hofmann
License
Source code in this card is licensed under the MIT License.
Posted by Henning Koch to makandra orga (2020-04-27 08:41)