Re: [LAU] (Ardour) How to get rid of delay when recording ?

From: <jonetsu@email-addr-hidden>
Date: Sat Feb 13 2016 - 23:50:18 EET

On Sat, 13 Feb 2016 15:18:53 -0600
Daniel Sheeler <dsheeler@pobox.com> wrote:

Thanks for the replies !

> I'm assuming you're using jack... The delay is I think from your jack
> buffer size and number of periods.  The smaller the jack buffer and
> number of periods, the smaller you make the delay you hear.  I'm
> hoping your buffer size is kinda big like 1024, whereas it could be
> as small as maybe 32 or 64.  I am not sure what you'll need to make
> it before you are fine with the delay.  
>
> All that said, do you know how to adjust the buffer size and number of
> periods?  If so, try making buffer size smaller until you can tolerate
> the echo.  Too small and you might get too many xruns.  

The system is Linux Mint 17. A 'ps aux' shows:

/usr/bin/jackd -T -ndefault -t 200 -p 2048 -R -T -d alsa -n 2 -r 44100
-p 1024 -d hw:M1010LT,0 -X raw

I tried to find the place in /etc/init.d/ where this command is written
and haven't found anything. So far I thought that everything in a
Linux system would be launched from there. I did a serach on various
terms such as 'jackd', '44100'. Strange.

So I copied/pasted the ps aux line above, changed '-p 1024' to '-p 128'
then logged in as root, killed the existing jackd process (no audio app
running) then pasted the new line. But this happened:

This is free software, and you are welcome to redistribute
it under certain conditions; see the file COPYING for details

JACK server starting in realtime mode with priority 10

Failed to connect to session bus for device reservation Did not
receive a reply. Possible causes include: the remote application did
not send a reply, the message bus security policy blocked the reply,
the reply timeout expired, or the network connection

Audio device hw:M1010LT,0 cannot be acquired...

Cannot initialize driver
JackServer::Open failed with -1
Failed to open server

So I then used qjackctl, changed the value which was 1024, to 128, and
*rebooted*. Now it runs with:

/usr/bin/jackd -T -ndefault -dalsa -dhw:M1010LT -r44100 -p128 -n2

This is quite different from the original one. Moreover, it does no
good at all. There's crackling all over. Renoise cannot scroll the
sequences properly, it is no good at all.

So...

1) Where the hell does the first incantation of jackd comes from ? And
where do the parameters comes from ?

2) How come it cannot be started from the command line by pasting the
command line that is currently *running* as shown in 'ps aux'

3) Why are the new parameters so different, lacking many original
options ?

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Received on Sun Feb 14 00:15:02 2016

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