Ttyjfyk

So Pulseaudio has a built-in equilizer loaded with

module-equalizer-sink

According to http://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Equalizer, you can control it with the qpaeq GUI.

Is there a way to congfigure PA equilizer on a Xless system (running in session mode) ?

The pulseaudio equalizer is reading his settings in the user file ~/.config/pulse/equalizerrc

To display it:

cat ~/.config/pulse/equalizerrc

So, as example, to give a value of 10DB on the 5th band of the eq, and directly ear the change:

sed -i '19s/.*/10.0/' ~/.config/pulse/equalizerrc | pulseaudio-equalizer toggle

To explain furthermore, sed will replace all line numbered 19, and will replace it by 10.0 on the config file, then the equalizer is restarted/toggled to get the result.

Here's a script called connect-one-eq, adapteded from qpaeq that comes with Pulseaudio:

#!/usr/bin/env python
import os,math,sys
import dbus

def connect(): # copied from qpaeq
 try:
 if 'PULSE_DBUS_SERVER' in os.environ:
 address = os.environ['PULSE_DBUS_SERVER']
 else:
 bus = dbus.SessionBus() # Should be UserBus, but D-Bus doesn't implement that yet.
 server_lookup = bus.get_object('org.PulseAudio1', '/org/pulseaudio/server_lookup1')
 address = server_lookup.Get('org.PulseAudio.ServerLookup1', 'Address', dbus_interface='org.freedesktop.DBus.Properties')
 return dbus.connection.Connection(address)
 except Exception as e:
 sys.stderr.write('There was an error connecting to pulseaudio, '
 'please make sure you have the pulseaudio dbus '
 'module loaded, exiting...n')
 sys.exit(-1)

def get_sink(str):
 connection=connect()
 path='/org/pulseaudio/core1/sink%s'%str
 sink=connection.get_object(object_path=path)
 return sink

args = sys.argv[1:]

sinkname = args.pop(0);
sink = get_sink(sinkname);

sys.stderr.write(str(sink)+'n')

prop_iface='org.freedesktop.DBus.Properties'
eq_iface='org.PulseAudio.Ext.Equalizing1.Equalizer'
sink_props=dbus.Interface(sink,dbus_interface=prop_iface)

def get_eq_attr(attr):
 return sink_props.Get(eq_iface,attr)

sample_rate=get_eq_attr('SampleRate')
filter_rate=get_eq_attr('FilterSampleRate')
nchannels=get_eq_attr('NChannels')

sys.stderr.write('channels %d, sample rate: %f, filter sample rate: %fn'%
 (nchannels, sample_rate, filter_rate))

def translate_rates(dst,src,rates):
 return list([x*dst/src for x in rates])

def translate_freqs(freqs):
 translate_rates(filter_rate,sample_rate,
 freqs)

channel = int(args.pop(0));
preamp = float(args.pop(0));
freqs = [];
coeffs = [];
while len(args) > 0:
 sys.stderr.write('(%s, %s)n'%(args[0],args[1]))
 freqs.append(float(args.pop(0)))
 coeffs.append(float(args.pop(0)))

# for some reason this fixes the types of the arguments to SeedFilter
sink=dbus.Interface(sink,dbus_interface=eq_iface)

# set the filter coefficients
sink.SeedFilter(channel,freqs,coeffs,preamp)

First you want to load the equalizer module as well as the DBus protocol module:

pactl load-module module-dbus-protocol
pactl load-module module-equalizer-sink sink_name=... sink_master=...
pactl set-default-sink ...

Use pacmd list-sinks to get the sink number.

Then make some noise, or music or whatever:

play -n synth pinknoise gain -10

Then call the script with the sink number, the channel index you want the equalizer to apply to, a preamp (scaling) factor, and a list of (frequency, coefficient) pairs. The frequency list doesn't have to be dense, since it is interpolated (see seed_filter in pulseaudio/src/modules/module-equalizer-sink.c). If you specify the total number of channels as the channel index then the update applies to all channels.

For example, if the sink number is 12 and it has 2 channels, then this resets the equalizer to all 1's, as you can verify by opening qpaeq:

./connect-one-eq 12 2 1.0 0 1.0 32768 1.0

The frequencies are 0 and 32768 (the maximum), and the coefficients are 1.0 and 1.0, which are interpolated to give a gain 1.0 at all intermediate frequencies.

The following example (in Bash) makes a filter that goes up and down in frequency, a bit like a siren:

SINKNUM=12; NCHAN=2;
while true; do
 for i in $(seq 500 10 1500) $(seq 1500 -10 500); do
 ./connect-one-eq $SINKNUM $NCHAN 1 
 0 1 $(( $i - 300 )) 1 
 $i 5 $(( $i + 300 )) 1 
 32768 1;
 done;
done

I believe the command is pacmd.

EDIT:

If you go to:

/usr/share/pulseaudio/alsa-mixer/profile-sets

You will find a number of configuration files. You may want to try editing default.conf.

consider pulseaudio-mixer-cli from here. it's a python based script providing text based individual stream volume controller:

[++] Jack sink (PulseAudio JACK Sink) M [ ########################## ]
[++] HDMI 0 (hdmi-stereo@snd_hda_intel) M [ ########################## ]
[81] ID 440 Analog (snd_hda_intel) - [ #####################----- ]
[35] mpv - Bax - Perceptions 206 on ETN.fm - [ #########----------------- ]
[38] VLC media player (fraggod@malediction) - [ ##########---------------- ]
[54] Skype (fraggod@malediction:24202) - [ ##############------------ ]
[27] ALSA plug-in [PillarsOfEternity] - [ #######------------------- ]