Optional safe start volume for every output when it connects or becomes the default

[mmsmsy]

Problem

Several reports describe the same painful moment: an output becomes active at a high volume and blasts the user before they can react.

• Bluetooth earbuds connect at 100% volume, overriding saved volume #17986: Bluetooth earbuds connect at 100%, whatever the system volume was.
• Audio turns to 100% after connecting to a bluetooth device #11832: audio jumps to 100% after a Bluetooth device connects.
• Bluetooth headset volume can drift from what PC shows — host should push it back as authoritative #12401 and Bluetooth headset volume partly disconnected from audio panel #11683: the Bluetooth headset's own volume drifts from the volume the PC shows.

I hit a version of this too. I switched from headphones (left at 100%) to a Bluetooth speaker that showed 20%. The first touch of the volume slider jumped it to 100%, so the speaker blasted for a second. The cause was AVRCP absolute volume: the slider drove the speaker's own volume, and the speaker's own value and the PC's value disagreed.

What I use now

The rule is simple: every output starts at 15% when it connects or becomes the default output. The device itself stays at 100% of its own range, and the system slider is the only volume control.

1. A WirePlumber drop-in, ~/.config/wireplumber/wireplumber.conf.d/volume-start-15.conf:

wireplumber.settings = {
  device.restore-routes = false
  device.routes.default-sink-volume = 0.003375   # 0.15^3, 15% on the wpctl/pactl scale
}

monitor.bluez.properties = {
  bluez5.enable-hw-volume = false
}

monitor.alsa.rules = [
  {
    matches = [ { device.name = "~alsa_card.*" } ]
    actions = { update-props = { api.alsa.soft-mixer = true } }
  }
]

2. A small user service. When the default sink changes, it sets both the new default and the sink just left to 15%. The second part matters: the next time you switch back, that sink is already at 15%, so there is no loud moment before the script reacts.

#!/bin/bash
export LC_ALL=C
VOL="${AUDIO_SWITCH_VOLUME:-15%}"

set_vol() {
  local s
  s="$(omarchy-audio-output-sink "$1" 2>/dev/null)"
  [[ -n $s ]] || s="$1"
  pactl set-sink-volume "$s" "$VOL" 2>/dev/null
}

last="$(pactl get-default-sink 2>/dev/null)"

pactl subscribe | while read -r line; do
  [[ $line == *"'change' on server"* ]] || continue
  cur="$(pactl get-default-sink 2>/dev/null)"
  [[ -n $cur && $cur != "$last" ]] || continue
  set_vol "$cur"
  pactl list sinks short 2>/dev/null | awk '{print $2}' | grep -qxF -- "$last" && set_vol "$last"
  last="$cur"
done

How to install

1. Save the WirePlumber drop-in above as ~/.config/wireplumber/wireplumber.conf.d/volume-start-15.conf.
2. Save the switch script above as ~/.local/bin/audio-switch-volume and make it executable: chmod +x ~/.local/bin/audio-switch-volume
3. Save this user service as ~/.config/systemd/user/audio-switch-volume.service:

[Unit]
Description=Set audio outputs to 15% when the default output changes
After=wireplumber.service pipewire-pulse.service
PartOf=pipewire.service

[Service]
ExecStart=%h/.local/bin/audio-switch-volume
Restart=always
RestartSec=2

[Install]
WantedBy=default.target

4. Turn it on and load the WirePlumber change:

systemctl --user daemon-reload
systemctl --user enable --now audio-switch-volume.service
systemctl --user restart wireplumber

Warning: before the restart, pause playback. If a Bluetooth device used hardware volume until now, its own level can be very low after the change. Mute the stream, set the device to its own maximum, then unmute. To change the level, set AUDIO_SWITCH_VOLUME (for example 20%) in the service and set device.routes.default-sink-volume to the same level cubed (0.2^3 = 0.008).

Trade-offs

• With hardware volume off, the device's own buttons change the device's own level, and the PC slider does not show that. Set the device to its maximum once.
• device.restore-routes = false also stops the restore of microphone levels. Every microphone input, built-in, USB or Bluetooth, starts at 100% (device.routes.default-source-volume is 1.0 by default).
• api.alsa.soft-mixer = true applies to every ALSA card, laptop speakers included. The hardware mixer stays where it is (set it to full scale once), and only software sets the volume.
• Software attenuation of a Bluetooth stream lowers its effective bit depth. I cannot hear a difference at normal listening levels.

Note: bluez5.hw-volume = [ ] did nothing for me. The property that works is bluez5.enable-hw-volume = false.

Setup: Omarchy 4.5.0-3, PipeWire 1.6.9, WirePlumber 0.5.18.

Suggestion

An opt-in setting, for example "start every output at N%" in the audio panel, plus the WirePlumber drop-in and a switch watcher like the one above. #17986 proposes per-device memory instead. Both can exist: a remembered level, but never above a safe limit when a device connects or becomes the default.