[pulseaudio-tickets] [Bug 98377] Poor Audio Quality on iMac 2011 27 Inch - Solution inside

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=98377

Dylan Taft <dylanetaft at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|OSX                         |Poor Audio Quality on iMac
                   |                            |2011 27 Inch - Solution
                   |                            |inside

--- Comment #1 from Dylan Taft <dylanetaft at gmail.com> ---
Was told to file a bug in #pulseaudio for this.  It's more of a missing feature
than a bug?  Basically Audio sounds awful on Linux compared to MacOS.  I slept
on it, and thought maybe apple doesn't do hardware bandpass filtering.

The iMac audio is exposed as surround 4.0,  that's not right.  It's actually
two high range speakers, and two speakers capable of bass. I'm not going to use
the terms tweeter and sufwoofer, I don't think that's quite right.  A simple
highpass\lowpass filter didn't seem to be good enough in testing, didn't sound
anything like OSX.

I managed to get something together in Alsa with a LADSPA filter.   I would say
running the speakers without any type of filter would probably damage them, it
sounds that bad. 

This is all abstracted away from the user in OSX, it "just works", but it's
pretty apparent they are doing "black magic" to the audio in software.  This
sounds _very_ close.  OSX you have no control over what frequencies are sent to
the 4 speakers.

Furthermore, does Pulse have the ability to apply LADSPA filters to sinks _per
channel_?  I saw a way to do it per sink, but you'd have to split sinks into 4,
apply LADSPA filters, and then recombine.


LADSPA FILTER: CAPS http://quitte.de/dsp/caps.html#Install
ALSA Audio volume settings:
MASTER 100, Speaker 73, Bass 94

This will combine the PCMs into one and apply filtering.
.asoundrc
pcm.default pulse

pcm.upmix20 {
    type route
    slave.pcm "plug:bandpass"
    slave.channels 4
    ttable.0.0 0.70
    ttable.1.1 0.70
    ttable.0.2 0.90
    ttable.1.3 0.90
}



pcm.bandpass {
        type ladspa
        #slave.pcm "plug:mydmix"
        slave.pcm "plughw:CARD=PCH,DEV=0"
        #slave.pcm "dmix:CARD=PCH,DEV=0"
        path "/usr/lib/ladspa"
    channels 4 
    plugins {
        0 {
            id 1773 #per listplugins
            policy none
            input.bindings.0 "in";
            output.bindings.0 "out";
            input {
                controls [ -48 -48 -48 -48 -30 -36 -30 -20 -4 5 ]
            }
        }
        1 {
            id 1773
            policy none
            input.bindings.1 "in";
            output.bindings.1 "out";
            input {
                controls [ -48 -48 -48 -48 -30 -36 -30 -20 -4 5 ]
            }
        }
        2 { #bass
            id 1773
            policy none
            input.bindings.2 "in";
            output.bindings.2 "out";
            input {
                controls [ 3 5 -4 -30 -35 -40 -40 -40 -48 -48 ]
            }
        }
        3 { #bass
            id 1773
            policy none
            input.bindings.3 "in";
            output.bindings.3 "out";
            input {
                controls [ 3 5 -4 -30 -35 -40 -40 -40 -48 -48 ]
            }
        }
    }
}

-- 
You are receiving this mail because:
You are the assignee for the bug.
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/pulseaudio-bugs/attachments/20161022/0e16130d/attachment.html>