### Summary

On ASUS ROG installs, `install/user/hardware/asus/fix-audio-mixer.sh` enables WirePlumber `api.alsa.soft-mixer = true` and then sets the Realtek ALC285 hardware `Master` to **80% unmute**.

With soft-mixer on, PipeWire never touches that hardware control again — the bar slider only moves the software path. So **100% in the UI is not full volume**; it is 100% of an 80% hardware ceiling (~**−12.75 dB** measured here). The desktop looks maxed out while Linux is still holding back.

The script comment (and the commit that added the line) is about **unmuting** a control that is often muted by default. Soft-mixer itself is intentional (Realtek muffled-audio workaround). The unexplained part is leaving Master at 80% forever under that soft-mixer — a fake limitation relative to what the hardware and the UI both claim to offer. Grown-ups who want full volume should be able to reach it when the bar says 100%.

### Measured on one machine

Hardware: ASUS ROG Zephyrus G16 (`GA605KM`), ALC285 + 2× CS35L56 amp path.

```text
$ aplay -l | grep -i ALC285
card 2: Generic_1 [HD-Audio Generic], device 0: ALC285 Analog [ALC285 Analog]

$ amixer -c 2 sget Master   # at install-like 80%
Mono: Playback 70 [80%] [-12.75dB] [on]

$ amixer -c 2 sget Master   # at 100%
Mono: Playback 87 [100%] [0.00dB] [on]
```

Limits are `Playback 0 - 87` (0.75 dB/step). 80% lands on step 70 → **−12.75 dB** relative to full scale. That matches the step math exactly (not a guessed −20 dB).

Soft-mixer conf is present at `~/.config/wireplumber/wireplumber.conf.d/alsa-soft-mixer.conf` (from `default/wireplumber/wireplumber.conf.d/alsa-soft-mixer.conf`).

### Persistence

`fix-mic.sh` (same ASUS user-hardware area) runs `alsactl store` for the ALC285 card into `/var/lib/alsa/asound.state`, and `alsa-restore.service` reapplies it at boot. There is no migration that later raises `Master`, so existing installs keep the capped value across updates.

### Why this matters

Same laptop, Windows is louder; on Omarchy the bar already shows 100%. The gap is this hidden hardware Master, not the user's ears or a broken slider. You only find it if you dig into `amixer` on the ALC285 card.

On this G16, Master **100%** is clean in normal use (no distortion noted at full scale). Soft-mixer can stay — the ask is that "100%" mean full scale for people who want it. If some ROG amps still need headroom, that is a fair maintainer call (options below), not a reason to leave every machine capped by default.

### Options (happy to implement whichever you prefer)

1. **Raise to 100% unmute** for all `omarchy-hw-asus-rog` machines (plus a small migration for existing installs that already stored 80%). Note this G16 has CS35L56 amps; if #8359's smart-amp concerns apply, prefer option 3.
2. **Unmute only** — stop setting a level in `fix-audio-mixer.sh`.
3. **DMI-narrow** the level raise (keep soft-mixer broad; only force 100% on known-good boards).

I can send a PR + migration + shell wiring test once there is a preferred option. If the answer is deliberate headroom on some boards, option 3 (DMI-narrow) keeps full volume for known-good machines without forcing every ROG amp.

### Related

- #8359 — blanket soft-mixer vs smart-amp ROG (different ask; this report does **not** propose removing soft-mixer)
- #7458 — unmute path too narrow outside ALC285 (sibling mechanism)
- #4821 — Strix G16 soft-mixer / hardware unmute history

### References

- `install/user/hardware/asus/fix-audio-mixer.sh` (commit that added Master 80%: "Ensure master volume isn't muted either")
- `default/wireplumber/wireplumber.conf.d/alsa-soft-mixer.conf`
- `install/user/hardware/asus/fix-mic.sh` (`alsactl store`)