Disable LFE remixing by default

System Internals / PulseAudio - Alexander E. Patrakov [gmail.com] - 24 May 2016 11:34 UTC

The current LFE crossover filter removes low frequencies from the main channels and puts them into the LFE channel with the wrong amplitude. It is not known for sure what is the correct relative amplitude (acoustic measurements are required with real hardware), and changing that might introduce a new bug, "it clips the LFE channel".

So just disable the feature by default until a better understanding emerges how it should work. This, essentially, returns the defaults to their state as of PulseAudio 6.0.

Some more observations:

- Most of available active analog speakers on the market do the necessary crossover filtering already, and HDMI receivers can be configured to do that, too, so a crossover filter in PulseAudio is harmful in these use cases.

- The "laptop with a builtin subwoofer" use case requires manual configuration anyway because the default crossover frequency (120 Hz) is wrong for laptop speakers.

- Finally, Windows 10 with a built-in USB audio driver does not synthesize the LFE channel given a 5.1 card and a stereo audio stream by default.

Hides: https://bugs.freedesktop.org/show_bug.cgi?id=95021

adbaae7 Disable LFE remixing by default
man/pulse-daemon.conf.5.xml.in | 4 ++--
src/daemon/daemon-conf.c | 4 ++--
src/daemon/daemon.conf.in | 4 ++--
src/pulsecore/core.c | 4 ++--
4 files changed, 8 insertions(+), 8 deletions(-)

Upstream: cgit.freedesktop.org

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