### System details

Mind 2,  Intel(R) Core(TM) Ultra 7 155H (12+8+2) @ 4.80 GHz, GeForce RTX 4060 Ti, Intel Arc Graphics,  Omarchy 4.0.4-1

### What's wrong?

[omarchy-debug.log](https://github.com/user-attachments/files/32468222/omarchy-debug.log)

**Environment**
Omarchy 4.0.4-1
PipeWire 1.6.8
WirePlumber 1.6.8
Device: Khadas Mind Graphics Speaker
USB VID:PID: 1234:0204
ALSA driver: snd_usb_audio

**Problem**

The built-in Khadas Mind Graphics Speaker has an incorrect volume mapping in PipeWire/WirePlumber.

In the Omarchy volume control, lowering the volume below roughly 98–100% results in no audible output.

The underlying ALSA volume control itself works correctly, so this does not seem to be a hardware volume range problem.

**ALSA behavior**

The device exposes a PCM playback control with a range of 0-128:

Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 128

Directly changing the ALSA mixer works normally:

PCM 16  -> 12%
PCM 32  -> 25%
PCM 64  -> 50%
PCM 96  -> 75%
PCM 128 -> 100%

However, the reported dB values are very small:

PCM 0   -> 0.00 dB
PCM 64  -> 0.25 dB
PCM 128 -> 0.50 dB

**PipeWire behavior**

Before the workaround:

wpctl set-volume <sink> 50%
amixer -c 0 get PCM

resulted in:

Playback 0 [0%] [0.00dB] [on]

The same happened at 80%:

wpctl set-volume <sink> 80%
amixer -c 0 get PCM
Playback 0 [0%] [0.00dB] [on]

Only 100% resulted in:

Playback 128 [100%] [0.50dB] [on]

So PipeWire accepts the requested volume, but the value gets mapped incorrectly to the ALSA mixer.

**Workaround**

I added the following WirePlumber rule:

```
monitor.alsa.rules = [
  {
    matches = [
      {
        device.name = "alsa_card.usb-KhadasCorp._Khadas_Mind_Graphics_Speaker_1234333333-00"
      }
    ]
    actions = {
      update-props = {
        api.alsa.ignore-dB = true
      }
    }
  }
]
```

Then restarted WirePlumber:

`systemctl --user restart wireplumber`

After that, the mapping works correctly:

PipeWire 50%  -> PCM 64  (50%)
PipeWire 80%  -> PCM 102 (80%)
PipeWire 100% -> PCM 128 (100%)

The full volume range is then usable normally.

**USB information**

The device identifies as:

ID 1234:0204 Brain Actuated Technologies Khadas Mind Graphics Speaker

It is a USB Audio Class 1.0 device and exposes a playback Feature Unit with Mute and Volume controls.

Possible cause

It looks like the ALSA runtime dB scale reported by this device is incorrect or otherwise unusable for hardware volume mapping.

The raw PCM range works correctly, and disabling dB-based volume handling with:

api.alsa.ignore-dB = true

fixes the problem.

**Possible fix**

It may be worth adding a device-specific WirePlumber rule for 1234:0204, or otherwise handling this device's incorrect dB scale.

The hardware PCM volume control itself appears to work correctly, so a virtual sink or software-volume workaround does not seem necessary.