ttoine at ttoine at
Fri May 2 14:01:30 BST 2008


It is not so easy. First of all, depending of the sound card chipset,
some will start with a period at 2, some at 3. As there is no database
about that point (I can't find one), anyone will have to test. It is a
good idea imho to create a wiki page with the tested setting of the user
community, but I don't know if it is easy to motivate people to fill that.

Second point, it is not compulsory to have a real time kernell in order
to start Jack. If well set up with a long latency (more than 60ms), it
can starts and works very well too.

Third point, the frames is the latest point to configure. I mean that
first, one has to set up the sample frequency he wants to work with
(44,1, 48, ...), then, try different period values (most of the time 2
or 3). And then, when RT is activated, it is possible to decrease the
frame value, so it will decrease the latency time. Basic sound cards
(like integrated chipsets) will not work well at latency below 20ms. And
some more professional sound chipset (M-Audio envy24, RME hdsp, etc...)
will start without matter at a period of 32 or 64, giving very low
latency around 2 or 3 ms at 48khz.

Depending the use, the latency has to be different. For example, if the
aim of the session is only to record a live performance, one can work
with a latency around 60ms to be sure of the quality of the result. If
the aim is to work on multi audio tracks with re-recording of musicians,
the lowest the latency is, the better it is for the musicians. And if
one wants to use midi, he will have to work around 8 ms or 10 ms to
avoid midi synchro problems.

So it means that people will have to test a bit, and configure depending
their sound card, and their need. And once it is well set up, it is
possible to save profiles for several uses and sound cards. Then, using
Patchage is not very difficult to explain.

A few month ago, I tried to write something on the ubuntu help wiki. The
problem is how to include on a ubuntu wiki page some screen capture ?
IMHO, it will be hard to write a good stuff for beginners on Qjackctl
without any screen capture. If you know how to do that, I would be glad
to help you.


hollunder at a écrit :
> Is the leader of the documentation team Murat Güneş? And if so, is he
> still not available?
> I feel the need to write a quick jack starter guide for new users,
> which covers the absolute basics to work with jack. But I need some
> advice, mainly because there are at least 3 articles that are similar,
> but don't really do the trick. Additionally, I never edited a wiki
> before.
> The guide, as I imagine it, in short words:
> 1. Make sure you have the rt-kernel
> 2. Make the appropriate settings in ubuntu studio controls
> 3. Make the necessary, stable settings in qjackctl, something like:
> frames 1024, periods3, rt
> 4. How to make basic connections using qjackctl, patchage
> Similar Articles:
> Advice appreciated.
> Best Regards,
> 	Philipp

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