[LAU] Console based software EQ for jack

[Patrick Shirkey]

On Fri, January 18, 2013 7:51 am, Stefan Stefanov wrote:
> Hi Julien
>
> In process of accomplish my task with EQ I discover a problem playing
> music with ecasound.
>
> If I execute: ecasound -i test.wav -o
> jack_multi,system:playback_1,system:playback_2
> then I get this error:
> "ERROR:  Connecting chainsetup failed: "All audio objects must have a
> common
> ... sampling rate; sampling rate of audio object "jack_multi" differs from
> ... engine rate (48000 <-> 44100); unable to continue."
> "
> I run jack like this: /usr/bin/jackd -P 85 -d alsa -P hw:2,0 -n 3 -p 256
>
> (test.wav format is 16,2,44100)
>

Jack is probably started with a sample rate of 48000.

You can of course start jack with a sample rate of 44100 or you can tell
ecasound to resample from 44100 to 48000.

Probably easier to tell jack to use 44100 though.




> Regards
> Stefan
>
>
> 2013/1/17 Julien Claassen <julien at mail.upb.de>:
>> Hello Stefan!
>>   Ecasound's basic concept is chains. A chain looks like this:
>> input -> possible processing options -> output
>>   So you can use jack intput and output:
>> ecasound -f:16,2,44100 -i jack_multi,mpd:out1,mpd:out2 -o \
>> jack_multi,system:playback_1,system:playback_2
>>   At the end of this line you can add effects. For example a filter. You
>> can
>> use LADSPA unique IDs or the labels. I prefer IDs, since I always forget
>> upper and lower case letters. So the GLAME Highpass IIR filter (label:
>> highpass_iir and ID 1890). It has two parameter cutoff and poles/stages.
>> You
>> can find that out with analyseplugin from the basic ladspa suite or look
>> it
>> up in your favourite graphic ladspa host. So at the end of the ecasound
>> line
>> we have:
>> -eli:1890,50,2
>> or
>> -el:highpass_iir,50,2
>>   Adds a highpass filter with 50Hz cutoff frequency and two
>> stages/poles.
>>   My favourite EQ is still Fons Adriaenson's 4-band parametric EQ
>> (1970). I
>> think the package is called 4-band parametric filter (or just filter).
>> It
>> has a lot of options, you can try them in your favourite graphical
>> application first and then copy all the values, that you found. probably
>> easiest for you.
>>   If you need more help ask. - one last note: the -f:16,2,44100 is the
>> ecasound audio formation option, see the manpage. It's
>> bitrate,number-of-channels,samplerate. So this is CD-quality. Adapt to
>> your
>> needs.
>>   Warmly yours
>>        Julien
>>
>> ----------------------------------------
>> http://juliencoder.de/nama/music.html
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--
Patrick Shirkey
Boost Hardware Ltd