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phate
Apprentice
Joined: 22 Mar 2004
Posts: 298
Location: Aachen, Germany
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 Posted: Mon Nov 19, 2007 4:24 pm Post subject: asound.conf: Filter for Subwoofer Channel? [nearly solved] |
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Hello,
can somebody tell me, why my asound.conf isn't working?
| Code: | #-----------------
# Volume
# ----------------
# volume of all channels
pcm.softvol {
type softvol # controler type
slave.pcm "multi" # redirect to
control {
name "SoftMaster" # controler name
card 0
}
}
# splitting the channels
pcm.multi {
type multi # controler type
slaves { # redirect to
a.pcm "front"
a.channels 2
b.pcm "rear"
b.channels 2
c.pcm "center_lfe"
c.channels 2
}
bindings {
0.slave a
0.channel 0
1.slave a
1.channel 1
2.slave b
2.channel 0
3.slave b
3.channel 1
4.slave c
4.channel 0
5.slave c
5.channel 1
}
}
# ---------------
# Upmix
# ----------------
pcm.upmix_50to51 {
type plug
slave.pcm surround51
slave.channels 6
ttable {
0.0 1
1.1 1
0.2 1
1.3 1
4.4 1
0.5 0.25
1.5 0.25
2.5 0.25
3.5 0.25
}
}
# ----------------
# overwrite existing devices
# ----------------
pcm.!surround50 {
type plug
slave.pcm "upmix_50to51"
}
pcm.!surround51 {
type plug
slave.pcm "softvol"
} |
With this configuration | Code: | | speaker-test -Dsurround51 -c6 -twav |
is working well, but | Code: | | speaker-test -Dsurround50 -c5 -twav |
fails with the message | Code: | | speaker-test: pcm_params.c:187: snd_pcm_hw_param_get_min: Assert »!snd_interval_empty(i)« failed. |
I had to translate this message from German, so it's possible, that it sounds a bit different.
Please help!
Last edited by phate on Sat Nov 24, 2007 1:12 am; edited 2 times in total |
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BradN
Advocate
Joined: 19 Apr 2002
Posts: 2391
Location: Wisconsin (USA)
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| Posted: Mon Nov 19, 2007 4:37 pm Post subject: |
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| Quote: | | can somebody tell me, why my asound.conf isn't working? |
Sorry for posting a useless response, but probably, because ALSA sucks and is buggy as hell with things like this. I tried to do a similar thing to upmix 2 channels to 4.1 and gave up because the plugins just won't work right. I tried 2 or 3 different sample configs and the best I could make work was copying channels. I would have liked to get a lowpassed output for the subwoofer, but I don't know if it's possible with the current state of things.
And, even when it did work, it did bad things to the buffer length, and almost any kind of activity would interrupt the sound. I gave up and just stuck with 2 channels. |
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phate
Apprentice
Joined: 22 Mar 2004
Posts: 298
Location: Aachen, Germany
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| Posted: Mon Nov 19, 2007 7:04 pm Post subject: |
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Well perhaps I should try to make my question more general: Is there a working method to filter the subwoofer channel with alsa by now? I've read quiete a lot in the alsa wiki about this toppic, but nothing really worked yet. Would be really happy to read some advise! Thanks!
I've managed so far to get 2.0 sound being played by all my 5 satellites, but the subwoofer is sounding awful. |
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PaulBredbury
Watchman
Joined: 14 Jul 2005
Posts: 7310
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| Posted: Mon Nov 19, 2007 9:46 pm Post subject: |
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Try with/without plug:
| Code: | | speaker-test -D plug:surround51 -c 6 -t wav |
See wiki.
I'm currently experimenting with, in ~/.asoundrc
| Code: | pcm.lowpass_21to21 {
type ladspa
slave.pcm upmix_21to51
path "/usr/lib/ladspa"
channels 3
plugins {
0 {
id 1098 # Identity (Audio) (1098/identity_audio)
policy duplicate
input.bindings.0 "Input";
output.bindings.0 "Output";
}
1 {
id 1672 # 4 Pole Low-Pass Filter with Resonance (FCRCIA) (1672/lp4pole_fcrcia_oa)
policy none
input.bindings.2 "Input";
output.bindings.2 "Output";
input {
controls [ 300 2 ]
}
}
}
}
pcm.upmix_20to51 {
type plug
slave.pcm "lowpass_21to21"
slave.channels 3
ttable {
0.0 1 # left channel
1.1 1 # right channel
0.2 0.5 # mix left and right ...
1.2 0.5 # ... channel for subwoofer
}
}
pcm.upmix_21to51 {
type plug
slave.pcm surround51
slave.channels 6
ttable {
0.0 1 # front left
1.1 1 # front right
0.2 1 # rear left
1.3 1 # rear right
0.4 0.5 # center
1.4 0.5 # center
2.5 1 # subwoofer
}
} |
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PaulBredbury
Watchman
Joined: 14 Jul 2005
Posts: 7310
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| Posted: Wed Nov 21, 2007 3:29 pm Post subject: |
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I've got it working. It's great fun to play with, and makes the sound clearer, by only having the subwoofer handle bass, so the other speakers can operate without the distortion from pumping out bass themselves. The PCM to use in e.g. audacious is of course upmix_20to51.
Edit: Here's my ~/.asoundrc
The 100 value in the "controls" lines may want changing between something like 80 and 300, depending on the speakers and personal preference.
| Code: | # http://alsa.opensrc.org/SurroundSound
# http://alsa.opensrc.org/Low-pass_filter_for_subwoofer_channel_%28HOWTO%29
# Arch Linux: pacman -S ladspa blop swh-plugins libsamplerate tap-plugins cmt
# speaker-test -D upmix_20to51 -c 2 -t wav
# listplugins
# analyseplugin cmt
# http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html
pcm.lowpass_21to21 {
type ladspa
slave.pcm upmix_21to51
path "/usr/lib/ladspa"
channels 3
plugins {
0 {
id 1098 # Identity (Audio) (1098/identity_audio)
policy duplicate
input.bindings.0 "Input";
output.bindings.0 "Output";
}
1 {
id 1052 # High-pass filter
policy none
input.bindings.0 "Input";
output.bindings.0 "Output";
input {
controls [ 100 ]
}
}
2 {
id 1052 # High-pass filter
policy none
input.bindings.1 "Input";
output.bindings.1 "Output";
input {
controls [ 100 ]
}
}
3 {
id 1051 # Low-pass filter
policy none
input.bindings.2 "Input";
output.bindings.2 "Output";
input {
controls [ 100 ]
}
}
}
}
pcm.upmix_20to51 {
type plug
slave.pcm "lowpass_21to21"
slave.channels 3
ttable {
0.0 1 # left channel
1.1 1 # right channel
0.2 0.5 # mix left and right ...
1.2 0.5 # ... channel for subwoofer
}
}
pcm.upmix_21to51 {
type plug
slave.pcm surround51
slave.channels 6
ttable {
0.0 1 # front left
1.1 1 # front right
0.2 1 # rear left
1.3 1 # rear right
# Front left/right to center.
0.4 0.5
1.4 0.5
# Subwoofer, more powerful to compensate for bass-removal from other speakers.
# Would normally be 1.
2.5 2
}
} |
Edit: Formatting. Updated URLs.
Last edited by PaulBredbury on Sat Apr 30, 2011 12:56 am; edited 4 times in total |
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Spudgun
n00b
Joined: 26 Oct 2007
Posts: 30
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| Posted: Wed Nov 21, 2007 4:35 pm Post subject: |
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| Can this be done with a 2.1 sound system too? |
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PaulBredbury
Watchman
Joined: 14 Jul 2005
Posts: 7310
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| Posted: Wed Nov 21, 2007 6:02 pm Post subject: |
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I don't see why not, it's flexible. Main problem is the time it takes to figure out how the configuration file works  |
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phate
Apprentice
Joined: 22 Mar 2004
Posts: 298
Location: Aachen, Germany
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| Posted: Fri Nov 23, 2007 5:29 pm Post subject: |
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Hi there,
I didn't have any time until now to test this configuration. I wondered, whether there's a way to combine this with a software volume control, because there isn't another way to make my sound volume more silent and on it's default volume level it would simply wake up the whole neighborhood. I've tried the following, but everytime I do a
| Code: | | speaker-test -D upmix_20to51 -c 2 -t wav |
I get a
| Code: | | speaker-test: pcm_params.c:187: snd_pcm_hw_param_get_min: Assert »!snd_interval_empty(i)« failed. |
I had to translate this message from German, so it's possible, that it sounds a bit different.
The configuration I tried looks like this:
| Code: | #-----------------
# Volume
# ----------------
# volume of all channels
pcm.softvol {
type softvol # controler type
slave.pcm "multi" # redirect to
control {
name "SoftMaster" # controler name
card 0
}
}
# splitting the channels in front and rear
pcm.multi {
type multi # controler type
slaves { # redirect to
a.pcm "front"
a.channels 2
b.pcm "rear"
b.channels 2
c.pcm "center_lfe"
c.channels 2
}
bindings {
0.slave a
0.channel 0
1.slave a
1.channel 1
2.slave b
2.channel 0
3.slave b
3.channel 1
4.slave c
4.channel 0
5.slave c
5.channel 1
}
}
# ---------------
# Upmix (copied from your configuration)
# ----------------
pcm.lowpass_21to21 {
type ladspa
slave.pcm upmix_21to51
path "/usr/lib/ladspa"
channels 3
plugins {
0 {
id 1098 # Identity (Audio) (1098/identity_audio)
policy duplicate
input.bindings.0 "Input";
output.bindings.0 "Output";
}
1 {
id 1052 # High-pass filter
policy none
input.bindings.0 "Input";
output.bindings.0 "Output";
input {
controls [ 100 ]
}
}
2 {
id 1052 # High-pass filter
policy none
input.bindings.1 "Input";
output.bindings.1 "Output";
input {
controls [ 100 ]
}
}
3 {
id 1051 # Low-pass filter
policy none
input.bindings.2 "Input";
output.bindings.2 "Output";
input {
controls [ 100 ]
}
}
}
}
pcm.upmix_20to51 {
type plug
slave.pcm "lowpass_21to21"
slave.channels 3
ttable {
0.0 1 # left channel
1.1 1 # right channel
0.2 0.5 # mix left and right ...
1.2 0.5 # ... channel for subwoofer
}
}
pcm.upmix_21to51 {
type plug
slave.pcm surround51
slave.channels 6
ttable {
0.0 1 # front left
1.1 1 # front right
0.2 1 # rear left
1.3 1 # rear right
# Front left/right to center.
0.4 0.5
1.4 0.5
# Subwoofer, more powerful to compensate for bass-removal from other speakers.
# Would normally be 1.
2.5 2
}
}
# ----------------
# overwrite existing devices
# ----------------
pcm.!default {
type plug
slave.pcm "upmix_20to51"
}
pcm.!surround51 {
type plug
slave.pcm "softvol"
} |
Can me be helped?  |
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PaulBredbury
Watchman
Joined: 14 Jul 2005
Posts: 7310
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| Posted: Fri Nov 23, 2007 5:43 pm Post subject: |
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| Quote: | | slave.pcm surround51 |
That won't work if "surround51" isn't defined. See thread for defining it  |
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phate
Apprentice
Joined: 22 Mar 2004
Posts: 298
Location: Aachen, Germany
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| Posted: Fri Nov 23, 2007 6:07 pm Post subject: |
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Thank you so much,
| Code: | | speaker-test -D upmix_20to51 -c 2 -t wav |
is working now. One bad thing remains:
| Code: | | speaker-test -D default -c 2 -t wav |
complains the same way "upmix_20to51" did previously. Any idea how to fix this?
You are using dmix, but as I have read here, I don't need dmix if my sound card supports hardware mixing (I'm pretty sure it does).
My configuration changed only in one line, where "slave.pcm surround51" was replaced by "slave.pcm softvol". The naming isn't best, I will change this when everything is working. |
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phate
Apprentice
Joined: 22 Mar 2004
Posts: 298
Location: Aachen, Germany
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| Posted: Fri Nov 23, 2007 7:05 pm Post subject: |
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I've fixed this with the following:
| Code: | pcm.!default {
type asym
playback.pcm "upmix_20to51"
} |
When playing stereo mp3 files I notice something strange: My subwoofer makes sounds like "klong", it sounds a bit like it's being oversteered. I will try to describe the scenario:
- Let's use mplayer with software mixing turned on in it's properties.
- Case 1)
--- Let's set mplayer's own volume bar to 100%.
--- Let's set SoftMaster to 7%
- Results in a quiete silent output with a subwoofer klonking on every beat.
- Case 2)
--- Let's set mplayer's own volume bar to 50%.
--- Let's set SoftMaster to 40%.
- Results in very good, loud and clear sound.
Can somebody explain this?? 
Last edited by phate on Fri Nov 23, 2007 7:50 pm; edited 2 times in total |
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PaulBredbury
Watchman
Joined: 14 Jul 2005
Posts: 7310
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| Posted: Fri Nov 23, 2007 7:30 pm Post subject: |
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I use:
| Code: | # Subwoofer, more powerful to compensate for bass-removal from other speakers.
2.5 2 |
Try changing the 2 to 1, which will halve the volume. |
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phate
Apprentice
Joined: 22 Mar 2004
Posts: 298
Location: Aachen, Germany
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| Posted: Fri Nov 23, 2007 7:43 pm Post subject: |
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Thanks, that solved the subwoofer klonking 
But regarding the above described scenario: In case 2 (low volume in mplayer) the sound is perfect.
With high volume in mplayer the "normal" speakers are "scratching" a bit. This didn't happen in case 2 as described above. I'm not sure, but I have the slight feeling, that the more bass there's in a song, the more the speakers are scratching. I've already tried setting the frequency for the "controls" lines to 300, but it didn't help.
my current config |
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