[ardour-users] 48 channels on ardour

Thomas Vecchione seablaede at gmail.com
Wed Jul 18 00:44:53 PDT 2007


My first thought would be to make sure you have realtime permissions as the
regular user.

Easy way to tell?  Log on as root, do the problems go away?  If they do,
chances are your user is not enabled with realtime permissions.  I can't
speak for JackLab, but if they have it set up properly, it should just be a
matter of adding to the audio group.  If they don't have it set up properly,
exactly how to do it can vary, in most cases it would be editing one text
file to make sure the audio group has the appropriate permissions, and then
adding your user to the audio group.

Ok there might be an easier way to tell, I lied.  Can you start Jack with
Realtime Permissions?  the -R switch, or in QJackCtl there is a setting for
it.  If you can then it is probably enabled, and you may need to look
elsewhere.  For instance when I said my board was one of the few nForce4
chipsets that didn't have problems with audio when a PCI-E Video card was on
the bus, I wasn't lying.  I am not sure of the status now, but for a long
time after nForce4 was released, many were advised to stay away from it on
ANY OS for audio as it would cause dropouts whenever your video card sucked
up the bandwidth.  I believe I read JackLab was using e17 as the default
WM?  IN which case the 3D card probably isn't working to hard and you should
look elsewhere, but you should be having no problem, even on your OS drive,
playing back 4 tracks of audio continuously, except maybe if you are trying
to play back 24/192K audio or something;)  Even then though....

Out of curiosity, you are not running a lot of plugins etc are you that
might be eating up CPU?  What does Ardour or Jack report for CPU useage when
running them while playing back?

                Seablade

On 7/18/07, John Emmas <johne53 at tiscali.co.uk> wrote:
>
> ----- Original Message -----
> From: "Thomas Vecchione" <seablaede at gmail.com>
> Sent: 18 July 2007 07:06
> >
> > Remember it is NOT a linear degredation in available tracks when adding
> > recording and playback to the same drive.  You lose a LARGE chunk of
> > performance much faster.
> >
> Actually the problems I've encountered (occasional stuttering and other
> glitches) don't depend on recording at all.  They happen, even if I'm just
> playing back and not recording anything.  My drives are all 7200rpm but
> admittedly, I'm playing back from the same drive as my system's running
> from.
>
> After I installed OpenSuse, I was advised to install Jacklab which
> (I thought) was to give me a real-time kernel.  However, there was
> no improvement in performance as far as I could tell.... :-(
>
> John
>
>
>
> ----- Original Message -----
> From: "Thomas Vecchione" <seablaede at gmail.com>
> To: "Kevin Cosgrove" <kevinc at doink.com>
> Cc: <ardour-users at lists.ardour.org>
> Sent: 18 July 2007 07:06
> Subject: Re: [ardour-users] 48 channels on ardour
>
>
> > Or you would have to ahve limited resources, which the average home
> studio
> > has.  Remember it is NOT a linear degredation in available tracks when
> > adding recording and playback to the same drive.  You lose a LARGE chunk
> > of
> > performance much faster.
> >
> > Meaning, lets say, hypothetically a single 200 Gig 7200 RPM drive has
> the
> > capacity to do 32 tracks of playback(I pull this from my previous post,
> > but
> > still consider it a vast estimation) in real life.
> >
> > If you do one track recording, and 4 tracks playback, it does NOT equal
> 5
> > tracks of that 32 track capacity.  In fact more than likely you are
> > probably
> > bordering on using up a third of that disk performance with just that,
> > instead of the sixth you might expect, due to the amount the head might
> > have
> > to move around, to read from one section of the drive, and write to
> > another.
> >
> > Exactly how costly it is depends on many factors, how fragmented your
> > drive
> > is, how much reading and writing, etc.  but the end result is the same.
> > You
> > can record much more reliably if you record to a drive that is only used
> > for
> > recording, and read from a different drive.  And when you are talking
> > about
> > something on a limited time frame, that reliability can be important,
> for
> > instance doing playback of backing tracks in a live instance, while
> > recording your performance, not exactly uncommon.
> >
> >                    Seablade
> >
> > On 7/18/07, Kevin Cosgrove <kevinc at doink.com> wrote:
> >>
> >>
> >> On 18 July 2007 at 7:39, "John Emmas" <johne53 at tiscali.co.uk> wrote:
> >>
> >> > > 2 HDs would be better, one for recording to, one for playback,
> >> > >
> >> > This doesn't make sense to me.  Surely you'd have to play the
> >> > audio back from the same drive that it was recorded on - or
> >> > would you copy the audio from the record drive to the playback
> >> > drive after it's recorded?
> >>
> >> That does sound a bit confusing, doesn't it.  If a person is
> >> recording one part of a performance (e.g. guitar) along with a
> >> recording of other people (e.g. piano), then they'll need to hear
> >> the playback while they're recording.  Moving audio around during
> >> a tracking session doesn't sound fun.  One wouldn't have to be a
> >> purist about this.  It'd probably be fine to have the guitarist
> >> hear they're just recorded track playing back on the same drive
> >> where they'll be recoding overdubs.
> >>
> >> Certainly separating audio files and system (OS) files onto
> >> separated disks would be good.
> >>
> >> Cheers....
> >>
> >> --
> >> Kevin
> >>
> >>
> >> _______________________________________________
> >> ardour-users mailing list
> >> ardour-users at lists.ardour.org
> >> http://lists.ardour.org/listinfo.cgi/ardour-users-ardour.org
> >>
> >
>
>
>
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>
>
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> >
>
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