On Thu, Apr 29, 2010 at 1:25 PM, Ralf Mardorf <ralf.mardorf@alice-dsl.net> wrote:

Louigi Verona wrote:

Hey guys!

I was the one who tested this for Mike. I used Qtractor and Rakarrack.
In Qtractor I had Audio track 1 and Audio track 2.
Signal from track 1 was routed into Rakarrack and then into track 2.

The latency is there and quite audible.

Louigi.

Maybe it has nothing to do with this:

-------- Original Message --------
Subject: Re: [LAD] JACK Graph Internal Latency? (was Re: A small
article ...)
Date: Thu, 29 Apr 2010 11:17:31 +0200
From: Ralf Mardorf <ralf.mardorf@alice-dsl.net>
To: michael noble <looplog@gmail.com>
CC: linux-audio-dev@lists.linuxaudio.org
References: <s2q339c30111004281945ke03e953dp404e0b63e42b563d@mail.gmail.com>
<m2yeb4b5e1d1004282041j67fd5bcek60636d345c38ba0f@mail.gmail.com>
<l2y339c30111004282258rfd24b69bo3f86bbd54235ff12@mail.gmail.com>
<p2p339c30111004290202u6fec7788ka4b038632ac42c87@mail.gmail.com>

[snip]

I also wonder why JACK's zero-copy implementation could cause issues
for
audio apps. There was an issue for Qtractor, anyway, until today I
believed that there is no latency when using JACK in any way, excluded
connections regarding to the sound card.
I never noticed a latency, but maybe it's because I used this insert
connections for time related FX only, e.g. flanger and delay.

Interesting to read about latency I never was able to hear.

Ralf

But anyway, what version of Qtractor do you use? There was an issue related to a supposed zero-copy implementation for outdated versions of Qtractor, that a long time ago was fixed in SVN or even in the previously used CVS.

Ralf