# Audio: no bit-perfect path for external USB DACs — everything is resampled to 48 kHz

I'm an audio geek and I want Omarchy to deliver bit-perfect audio to my audio gear. I tried plugging in an external DAC - in this case a Dragonfly Audio Cobalt USB DAC - and it was showing 48 kHz input on things I knew were 44.1 kHz. Here's the solution I came up with using the built in agent - posting for comment in the event it's worth consideration in a future release.  



## What happens

On a stock install, PipeWire runs a fixed 48 kHz graph clock with
`default.clock.allowed-rates` unset, so every 44.1 kHz source — which is most
music: CDs, the majority of a typical FLAC library, Plex/Tidal/Qobuz streams —
is sample-rate-converted 44.1 → 48 k before it reaches the DAC. On an external
USB DAC that natively supports 44.1 kHz, that conversion is pure loss with
nothing gained.

Second, `default/wireplumber/wireplumber.conf.d/alsa-soft-mixer.conf` forces
`api.alsa.soft-mixer = true` for **every** ALSA card. For laptop codecs that's
a reasonable call (Realtek hardware-mixer quirks). But on a clean external DAC
with a working hardware volume control, it means any OS volume below 100% is a
software gain multiply + re-quantize — again, not bit-perfect — when the DAC
could have done the attenuation losslessly in its own domain.

Net: there is currently no configuration, command, or documentation in Omarchy
that gets a clean digital path to an external DAC.

## Who this is for

Users with an outboard USB DAC doing focused music listening. **Not** the
laptop-speaker majority — on internal speakers none of this is audible and the
current defaults are the right ones. So this is opt-in territory, not a default
flip (see options below).

## What I changed locally, and the result

Two drop-ins:

```
# ~/.config/pipewire/pipewire.conf.d/99-bitperfect.conf
context.properties = {
    default.clock.rate          = 48000
    default.clock.allowed-rates = [ 44100 48000 88200 96000 ]
}
```

```
# ~/.config/wireplumber/wireplumber.conf.d/99-dragonfly-bitperfect.conf
monitor.alsa.rules = [
  {
    matches = [ { node.name = "~alsa_output.*DragonFly_Cobalt.*" } ]
    actions = { update-props = {
      audio.format        = "S24_3LE"
      api.alsa.soft-mixer = false
    } }
  }
]
```

After `systemctl --user restart wireplumber pipewire pipewire-pulse`:

| Source        | DAC hardware rate (`/proc/asound/cardN/pcm0p/sub0/hw_params`) |
| ------------- | ------------------------------------------------------------- |
| 44.1 kHz file | 44100 (was 48000)                                             |
| 96 kHz file   | 96000                                                         |

`wpctl set-volume` now moves the DAC's own `PCM Playback Volume` control, so
OS volume stays bit-perfect. No application-side change was needed — `mpv`,
Tunarchy, browsers all inherit the native rate.

## Options, least to most invasive

1. **Docs only.** There is currently no audio/sound page in `manual/` at all.
   A short "Bit-perfect audio for external DACs" page — the `allowed-rates`
   drop-in, the hardware-vs-software-volume tradeoff, how to verify with
   `hw_params` — would cover it without changing anyone's setup.

2. **An opt-in command**, mirroring the existing `omarchy audio tuning`
   framework: `omarchy audio bit-perfect on|off|status`. `on` drops in the
   rate config and (optionally) a soft-mixer-off rule scoped to USB DACs;
   `status` reports the live graph/device rate. Self-verifying and reversible,
   same as the speaker tunings.

3. **Enable `allowed-rates` by default.** Honestly the weakest option:
   upstream PipeWire ships this exact file in `pipewire.conf.avail/10-rates.conf`
   **disabled**, and neither Fedora nor Ubuntu enable it by default, because
   rate-switching can produce audible artifacts (pops, relock gaps) on some
   Bluetooth, HDMI, and cheap USB interfaces. Cuts against the "consistent
   across all hardware" intent of the current audio defaults.

4. **Scope the global soft-mixer rule** to exclude `device.api = alsa` +
   `device.bus = usb` (or similar), so external DACs use hardware volume while
   laptop codecs keep software volume. Independent of the rate question.

## My preference

Option 1 or 2. Happy to open the PR for whichever direction you'd take — a
`manual/` page, or the `omarchy audio bit-perfect` command plus a migration,
following the `omarchy-audio-tuning` pattern.

## Environment

- Omarchy 4.0.0.alpha
- PipeWire 1.6.8, WirePlumber 0.5.17
- AudioQuest DragonFly Cobalt (USB), also relevant to any USB/S-PDIF DAC