Low latency for Reaper on PipeWire

setup-pw.sh

#!/bin/sh

# Reaper reports latency of 4ms with this config.
#
# It may also be a good idea to use "Pro Audio" audio profile
#
#  $ pactl list short cards
#  $ pactl set-card-profile YOUR_CARD_NAME pro-audio
#

mkdir -p ~/.config/pipewire/pipewire.conf.d
mkdir -p ~/.config/pipewire/jack.conf.d/

# NOTE: adjust allowed clock rates according to your sound interface
# these are optimal for Focusrite Scarlett 2i2 gen3
cat > ~/.config/pipewire/pipewire.conf.d/10-clock-rate.conf << EOF
context.properties = {
  default.clock.allowed-rates = [ 48000 96000 192000 44100 88200 176400 ]
  default.clock.rate  =    48000
}
EOF

cat > ~/.config/pipewire/jack.conf.d/10-reaper.conf << EOF
jack.rules = [
    {
        matches = [
            { client.name                = "REAPER" },
            { application.process.binary = "reaper" }
        ]
        actions = {
            update-props = {
                node.latency       = 256/96000
                node.rate          = 1/96000
                node.quantum       = 256/96000
                node.lock-quantum  = true
                node.force-quantum = 256
            }
        }
    }
]
EOF