I don't use zoom (no need for the time being) but in my PulseAudio-less Daedalus box your tests work as shown. 8^)

So thank you very much for taking the time to research and write up these very clear explanations / instructions.

Best,

A.

The Zoom Workplace client is built to use ALSA as a first-class audio backend. As long as your system’s ALSA configuration supports full-duplex audio (simultaneous playback and recording), Zoom can access the microphone and speakers without additional tools.

Debian, Devuan, and many other Linux distributions enable full-duplex by default in their ALSA setup — meaning no user configuration is required. Tools like arecord and aplay can test this:

arecord -f cd -V mono | aplay

If you see a VU meter, full-duplex is active — and Zoom will work immediately.

Zoom does not rely on dmix or dsnoop plugins unless custom configurations demand them. It accesses the default PCM devices directly, which is why it functions reliably on minimal or pure ALSA systems.

Zoom relies entirely on the underlying ALSA setup to provide full-duplex audio (simultaneous playback and recording). If your sound card or ALSA configuration does not support full-duplex — either through hardware capabilities or proper software configuration (e.g., using dmix and dsnoop, or a full-duplex PCM device) — Zoom cannot create that functionality on its own

However, Zoom can work around certain limitations when:

- The default PCM device is correctly configured (e.g., using plughw or a plug-type device).
- Full-duplex is achievable at the driver or configuration level.

But if your sound system cannot perform full-duplex audio (as tested via arecord | aplay), Zoom will not function properly, and you may experience one-way audio or dropped streams.

In short: Full-duplex must be enabled at the ALSA level — Zoom won’t add it if it’s missing.

Using Zoom Workplace with ALSA on Linux

Zoom Workplace for Linux works seamlessly with ALSA (Advanced Linux Sound Architecture) without requiring additional sound servers such as PulseAudio. In most cases, no special configuration is needed — even with custom ALSA setups.

You can download Zoom Workplace from: 
_https://zoom.us/download

Compatibility Overview

✅ Works out of the box with default ALSA configurations.
✅ Compatible with modified ALSA setups (e.g., those using fftrate resampling).
✅ Functions correctly with ALSA configurations generated by tools like arateconf.

How to Use Zoom with Default ALSA Settings

Even if you're new to Linux audio configuration, rest assured — everything should work straight away. Follow these steps to confirm your setup:

1. Ensure Default ALSA Configuration Is Active 
  If you've previously created a custom configuration file, remove it temporarily:
 

rm ~/.asoundrc

 
This ensures you’re using the standard system-wide ALSA settings (as provided by Debian, Devuan, or your distribution).
 
2. Identify Your Sound Card 
  List available sound cards:
 

cat /proc/asound/cards

   
Or check card IDs directly:
 

cat /sys/class/sound/card*/id

 
Note the name (e.g., PCH, system) — you’ll need this if your system has multiple audio devices.
 
3. Set the Default Sound Card (Optional – For Multi-Card Systems) 
  If you have more than one sound card, create a user-level configuration file:
 

nano ~/.asoundrc

 
Add the following lines, replacing PCH with your actual card name:
 

defaults.pcm.!card PCH
defaults.ctl.!card PCH

 
4. Connect a Microphone 
  Plug in an external microphone or ensure the built-in mic is available.
 
5. Adjust Microphone Volume 
  Open the ALSA mixer:
 

alsamixer

 
  - Press F4 to switch to capture (recording) controls.
  - Use the arrow keys to increase the microphone level.
  - Press Esc to exit.
6. Test Full-Duplex Audio 
Verify that your system can play and record simultaneously:
 

arecord -f cd -V mono | aplay

 
You should see a real-time VU meter indicating activity:
 

Recording WAVE 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Playing WAVE 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
###############+ 		| 29%

 
This confirms bidirectional audio is functioning.
 
7. Exit the Test 
  Press Ctrl+C to stop the recording and playback.

Installing and Testing Zoom

1. Install Zoom Workplace for Linux from the official website. _https://zoom.us/download
2. Launch it from the terminal:
 

zoom

 
3. Go to Settings > Audio.
4. Use the Test Microphone button to verify input and output.

Both microphone and speakers should function correctly with no further configuration.

With this setup, Zoom Workplace delivers reliable audio performance on pure ALSA systems—ideal for lightweight or minimal Linux installations.