Re: [LAU] On the fly bass downmixing to mono (mpd or alsa)?

From: Fons Adriaensen <fons@email-addr-hidden>
Date: Sun Feb 09 2014 - 23:27:05 EET

On Sun, Feb 09, 2014 at 03:08:41PM -0600, Matt Garman wrote:

> I started the thread "How is the bass mixed? Per-channel frequency
> analysis? Histogram?" a few weeks ago. One suggestion that came up a
> few times was to simply downmix the bass to mono before sending it
> out.
>
> How would I go about this? Currently, this system doesn't have any
> audio. What I intend to do is send audio out over USB to a DAC.
> Ideally, I'd like to do on-the-fly remixing of only "bass frequencies"
> to mono. Ideally the frequency should be configurable, but I think
> about 150Hz or below is a good start.
>
> If possible, I'd like to keep things simple, and have only ALSA and
> MPD running. As far as I can tell, I don't think I can do this at the
> MPD level.

You really need to provide a bit more information here.

If your sub is an active one (with a built-in amplifier)
it will have the required filter. And probably it will
have two inputs which it will add to mono. So you just
connect the two outputs of your DAC.

Many active subs also provide outputs for the amplifier
of the main speakers, which will have the bass (which is
used by the sub) filtered out. In that case just connect
your main amplifier or active speakers there.

If your equipment is different, then at least provide a
clear and complete descriptn, nobody will be able to
help without that.

Note that it is normally more important to remove the
bass signal for the main speakers than to remove the
mid/high part for the sub.

Ciao,

-- 
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
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Received on Mon Feb 10 00:15:04 2014

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