Status update:
For alsa-lib, the surround21:x name is in 1.0.28, and 1.0.28 has been released into utopic.
For pulseaudio, not much has happened. The patch to use the "surround21:x" name is in PulseAudio git ( http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/modules/alsa/mixer/profile-sets/default.conf?id=3f140f9022ef0b59b3684edd25e2202a65989669 ) but there has been no upstream release of PulseAudio since this patch went in.
There has been some upstream discussions about how to best implement an LFE filter, but nobody has finished writing one yet. ( http://lists.freedesktop.org/archives/pulseaudio-discuss/2014-September/021824.html )
Status update:
For alsa-lib, the surround21:x name is in 1.0.28, and 1.0.28 has been released into utopic.
For pulseaudio, not much has happened. The patch to use the "surround21:x" name is in PulseAudio git ( http:// cgit.freedeskto p.org/pulseaudi o/pulseaudio/ commit/ src/modules/ alsa/mixer/ profile- sets/default. conf?id= 3f140f9022ef0b5 9b3684edd25e220 2a65989669 ) but there has been no upstream release of PulseAudio since this patch went in.
There has been some upstream discussions about how to best implement an LFE filter, but nobody has finished writing one yet. ( http:// lists.freedeskt op.org/ archives/ pulseaudio- discuss/ 2014-September/ 021824. html )