Hello, I believe that my problem is a format problem but I really don't find the way to solve it ! Here is my latest implementation : *INPUT -> OUTPUT:* /pcm.!default { # *INPUT* # type plug type route slave.pcm conversion_plug; # slave.pcm BassMax; # slave.pcm mix; # slave.pcm "plughw:0,0" slave.channels 2 #To get MONO out from Left Channel) ttable.0.0 0.5 ttable.1.0 0.5 ttable.0.1 0.5 ttable.1.1 0.5 } pcm.conversion_plug { # *CONVERSION PLUG* type plug # slave.pcm mix slave.pcm BassMax } pcm.BassMax { # *BASSMAX* type ladspa slave.pcm mix; path "/usr/lib/ladspa" channels 2 plugins { 0 { id 1098 # Identity (Audio) (1098/identity_audio) policy duplicate # Keep Left Channel unchanged input.bindings.0 "Input"; output.bindings.0 "Output"; } 1 { id 1672 # 4 Pole Low-Pass Filter with Resonance (FCRCIA) (1672/lp4p$ policy none # Apply Low Pass Filter to subwoofer mon$ input.bindings.0 "Input"; output.bindings.0 "Output"; input { controls [ 200 2 ] } } 2 { id 1220 # Overtone (Harmonics Generator) policy none # Apply Overtone to subwoofer mono Mix input.bindings.0 "Input"; output.bindings.0 "Output"; input { controls [ 1 -1 0 1 0.2 -1 -1 1 -1 -1 ] } } } } pcm.mix { # *OUPUT* # type plug type route slave.pcm "plughw:0,0" slave.channels 2 ttable { 0.0 0.5 # left channel = mono mix left and right$ 1.0 0.5 } }/ And here are the trials I made to get SOUND : *1/ INPUT -> OUTPUT:* #1 INPUT (type plug) -> OUPUT (type plug), I get an error: squeezelite: pcm_params.c:170: snd1_pcm_hw_param_get_min: Assertion `!snd_interval_empty(i)' failed. #2 INPUT (type plug) -> OUPUT (type route), I get sound #3 INPUT (type route) -> OUPUT (type plug), I get sound #4 INPUT (type route) -> OUTPUT (type route), I get sound *WHY ?* Anyway, I thought that different format type between INPUT and OUTPUT was THE solution, so I tried : *2/ INPUT -> BASSMAX -> OUTPUT :* #1 INPUT (type plug) -> BASSMAX -> OUPUT (type plug): squeezelite: pcm_params.c:170: snd1_pcm_hw_param_get_min: Assertion `!snd_interval_empty(i)' failed. #2 INPUT (type plug) -> BASSMAX -> OUPUT (route plug):, #3 INPUT (type route) -> BASSMAX -> OUPUT (route plug), #4 INPUT (type route) -> BASSMAX -> OUPUT (type plug), Produced the same error : [10:18:13.284316] test_open:130 hwparam init error: Invalid argument [10:18:13.286370] output_init_common:373 unable to open output device So,I tried to convert the type from route to plug: *3/ INPUT -> CONVERSION PLUG -> BASSMAX -> OUTPUT :* #1: INPUT (type route) -> CONVERSION PLUG (type plug) -> BASSMAX -> OUPUT (type plug): squeezelite: pcm_params.c:170: snd1_pcm_hw_param_get_min: Assertion `!snd_interval_empty(i)' failed. Aborted #2: INPUT (type route) -> CONVERSION PLUG (type plug) -> BASSMAX -> OUPUT (type route): [12:00:38.138447] test_open:130 hwparam init error: Invalid argument [12:00:38.140665] output_init_common:373 unable to open output device *This one should have worked !* Then I thought I should try again *without* the BASSMAX just to confirm it was working *4/ INPUT -> CONVERSION PLUG -> OUTPUT :* #1 INPUT (type route) -> CONVERSION PLUG (type plug) -> OUPUT (type route), YES, I got sound #2 INPUT (type plug) -> CONVERSION PLUG (type route) -> OUPUT (type plug), failed: [12:51:11.783791] test_open:124 playback open error: Invalid argument [12:51:11.785627] output_init_common:373 unable to open output device #3 atltough without any interest INPUT (type plug) -> CONVERSION PLUG (type plug) -> OUPUT (type route), also failed: squeezelite: pcm_params.c:170: snd1_pcm_hw_param_get_min: Assertion `!snd_interval_empty(i)' failed. Aborted #4 atltough without any interest INPUT (type route) -> CONVERSION PLUG (type route) -> OUPUT (type plug), also failed: [13:16:07.156408] test_open:124 playback open error: Invalid argument [13:16:07.158014] output_init_common:373 unable to open output device *It looks like I have to have the INPUT in type route* However, although I thought that the LADSPA might not like the INPUT in route type, I also tried to add the conversion plug in between BASSMAX and OUTPUT 5/ INPUT -> BASSMAX -> CONVERSION PLUG -> OUPUT # 1 INPUT (plug type) -> BASSMAX -> CONVERSION PLUG (type plug) -> OUPUT (type route), I got : squeezelite: pcm_params.c:170: snd1_pcm_hw_param_get_min: Assertion `!snd_interval_empty(i)' failed. Aborted # 2 INPUT (plug type) -> BASSMAX -> CONVERSION PLUG (type route) -> OUPUT (type plug), I got : [12:21:59.863034] test_open:124 playback open error: Invalid argument [12:21:59.864826] output_init_common:373 unable to open output device #3 INPUT (plug type) -> BASSMAX -> CONVERSION PLUG (type route) -> OUPUT (type route), I got : [12:25:25.686880] test_open:124 playback open error: Invalid argument [12:25:25.688497] output_init_common:373 unable to open output device #4 INPUT (plug type) -> BASSMAX -> CONVERSION PLUG (type plug) -> OUPUT (type plug), I got: squeezelite: pcm_params.c:170: snd1_pcm_hw_param_get_min: Assertion `!snd_interval_empty(i)' failed. Aborted #5 INPUT (type route) -> BASSMAX -> CONVERSION PLUG (type route) -> OUTPUT (type plug) I got: [12:32:08.213364] test_open:124 playback open error: Invalid argument [12:32:08.215192] output_init_common:373 unable to open output device #6 INPUT (type route) -> BASSMAX -> CONVERSION PLUG (type plug) -> OUTPUT (type route) I got: [12:34:21.398664] test_open:130 hwparam init error: Invalid argument [12:34:21.400769] output_init_common:373 unable to open output device *This one might have worked, unless LADSPA doesn’t accept route type as input* NOTE that: INPUT (type route) -> CONVERSION PLUG (type plug) -> BASSMAX -> PLUGHW works I get, from a 63Hz sine wave at the input, 126 Hz on the left Channel and 63Hz not attenuated on the right Channel. *So what are my left options ?* Best regards, Jean -- View this message in context: http://linux-audio.4202.n7.nabble.com/LADSPA-Plugins-from-ALSA-would-like-some-help-please-tp101061p101077.html Sent from the linux-audio-user mailing list archive at Nabble.com. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user