See: the PipeWire Wiki:
Try setting the following in ~/.config/pipewire/pipewire-pulse.conf
:
stream.properties = {
channelmix.mix-lfe = true
channelmix.upmix = true
channelmix.lfe-cutoff = 80
}
Then restart PipeWire:
systemctl --user restart pipewire pipewire-pulse pipewire-media-session