I'm doing some experiments to use Jack and NetJack to connect several machines. Here I'm using two Linux machines : a debian as client and mint 20 as server (sorry I'm not confortable with the "master" "slave" keywords in this context).
I'm sending 32 channels from client to server. By the way, this works great and is very intuitive.
Though, for some reason, when I connect these inputs to something (here to Reaper), audio is great until I connect the 26th input to Reaper. Then it starts glitching (sounds like interruption) and gets worst if I keep increasing the number of connections. If I remove connections to keep it less than 26, it sounds ok. Never had this problem before.
Is it likely related to NetJack ? Or does it sounds like a pure Jack issue ?
Thanks for any help or advice
Electroacoustic composer & computer music designer
+33 6 77 20 98 41
I've been gigging for years with a carefully fine-tuned manjaro box where I run jack with 4ms "internal" latency (-r 48000 -p 64 -n 3).
With my Presonus Audiobox 1818VSL, that leads to a roundtrip latency of ~5.7ms (as measured by jack_iodelay), which I'm very happy with.
Now tried replacing my 1818VSL with a Soundcraft ui24r, same jack settings. The roundtrip latency jumps to a rather unimpressive 9.9ms!
So the "added latency" is almost 3.5 bigger with the Soundcraft. That's a pity, because this really is a nice machine otherwise...
Is it expected to find such enormous differences between interfaces - or did I just forget the -Xmagical parameter that will fix it all?
Any idea welcome, I'd love so much to love this gear! ;-)
Hi Jonathan, thank you very much. What I need to do is relatively simple, I
think. I need to do a program that allows you to monitor your voice on your
headphones without latency, and which is compatible with different devices,
i.e., mac, windows, and android. Currently I do this using qjackCtl on my
mac and it works fine, but on a windows machine I have I get latency. So I
would like to learn how to handle jack from the command line to see if I'm
able to create a program which is user friendly, to implement this on
Thank you for your help, I will search for information with the resources
you gave me.
On Mon, Dec 12, 2022 at 8:00 AM <jackaudio-request(a)lists.linuxaudio.org>
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> Date: Mon, 12 Dec 2022 18:32:54 +1030
> From: Jonathan Woithe <jwoithe(a)just42.net>
> To: Rodrigo Yanez <rypptc(a)gmail.com>
> Cc: jackaudio(a)lists.linuxaudio.org
> Subject: Re: [Jackaudio] Hi, I'm new to JackAudio
> Message-ID: <Y5bgLlE3PaVznXDN(a)marvin.atrad.com.au>
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> Hi Rodrigo
> On Thu, Dec 08, 2022 at 07:51:53PM -0300, Rodrigo Yanez wrote:
> > I'm new to this mailing list and I don't know how to view previous mails
> > to check if what I'm going to ask is already on the mailing list.
> You can access an archive of previous posts at
> Admittedly this is not directly searchable.
> > I would like to learn how to use JackAudio from the command line. I
> > appreciate if you could let me know if there is a tutorial to familiarize
> > myself with JackAudio commands.
> You may like to start with the FAQs at
> along with the rest of the information available from
> The wiki linked from the above page may also be useful.
> It is difficult to be specific without knowing what you wish to do and the
> hardware platform and operating system you will be using.
>  https://github.com/jackaudio/jackaudio.github.com/wiki
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Hello, fellow Jack developers.
I am currently writing a jack client which is loaded from within the
unity3d game engine. It's supposed to work like this: Every time, jack
requests audio, unity3d generates it. This is done in order to bypass
the unity3d audio renderer and use the audio in different applications
Technically, everything works fine so far. When the software is started,
either from within the unity3d editor or directly as a compiled unity3d
application, the client appears in QJackCtl and I can route the channels
to wherever I want and even hear the audio.
BUT: the client randomly disables. At some point during runtime (both in
the built version and directly from the editor) it happens, that the
routing disconnects itself, and I am unable to reconnect it. When I try,
I get the message "Cannot connect ports owned by inactive clients:
"Unity" is not active".
This behavior seems to be very unpredictable, sometimes it happens after
just a second, sometimes it runs fine for over a minute or two.
Sometimes it does not even happen (or I did not wait long enough).
I have experienced this behavior both writing my own framework or by
using the JackSharp framework. The behavior also does not change when
uninstalling pulseaudio (which was sort of a last guess on our end).
The same behavior occurs when I use jack with a dummy driver. The
connection is established and randomly breaks down again. (although
obviously I can't hear the sound).
Interestingly: when I use the framework as a standalone version,
everything seems to work fine. Therefore, it kind of seems obvious, that
it has to have to do something with Unity or the fact, that the
framework is called from a different thread or something like that.
However, Unity does not report any problems.
What I can see in the QJackCtl Log: The exact moment the problem occurs,
the kPortRegistrationOff Method is called on all ports. It looks like
the server disables all ports, then tries to deactivate the client and
therefore destroying all the ports. It eventually proceeds to tell, that
the client was destroyed successfully and that's it.
I have implemented all the callbacks that are available from the API (at
least all that i think where usefull) but all I get is, that the
framework receives the jack_on_info_shutdown method is called. This
method is passed a const char argument which is supposed to hold the
reason, but all it says is : "JACK server has been closed". Which it is
not. It is still running.
At this point, I am out of ideas of what to do to narrow down the problem.
I have tested other applications (like Reaper) and they work fine.
I am using Ubuntu 20.04, both on low-latency or generic kernel > 5.14
I use the latest version of jack2 (as of Dec 22)
I know all this sounds very vague and overly complex, but I have no idea
what else to look for or which information may be necessary to further
investigate the problem.
Any help at all is highly appreciated.
Thank you all very much
Have a nice day
Hi, I hope I'm not spamming. I'm new to this mailing list and I don't know
how to view previous mails to check if what I'm going to ask is already on
the mailing list. I would like to learn how to use JackAudio from the
command line. I would appreciate if you could let me know if there is a
tutorial to familiarize myself with JackAudio commands.
Thank you very much.