[ardour-users] 48 channels on ardour

Thomas Vecchione seablaede at gmail.com
Tue Jul 17 23:47:03 PDT 2007


Resending as once again I forgot to hit reply to all...

                Seablade

---------- Forwarded message ----------
From: Thomas Vecchione <seablaede at gmail.com>
Date: Jul 18, 2007 1:45 AM
Subject: Re: [ardour-users] 48 channels on ardour
To: John Emmas <johne53 at tiscali.co.uk>


>
> 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?

The reason I proposed two for many people, is that they often won't record
all their tracks at once, but instead track the music, meaning they might
record the drums at one point, piano then might be recorded listening to the
drums, then vocals listening to both the drums and piano, etc.

Having the playback happen on one drive, while the actual recording happens
on the other in such cases, while help keep the head from having to skip all
over the drive in order to write on one area of the drive, while trying to
read from another area of the drive.  If you are recording everything at
once, and not doing any playback while recording, it doesn't make much
difference.  But for many people, tracking is fairly common practice, for
many reasons, limited inputs, limited space, limited isolation(Related to
limited space but not directly the same) limited musicians, etc, and thus
would help them.

               Seablade

On 7/18/07, John Emmas <johne53 at tiscali.co.uk> wrote:

> Thanks guys, I appreciate the advice.
>
> Thomas, you said something that confused me....
>
> >
> > 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?
>
> Thanks,
>
>
> John
>
> ----- Original Message -----
> From: "Thomas Vecchione" < seablaede at gmail.com>
> To: "John Emmas" <johne53 at tiscali.co.uk>
> Cc: < ardour-users at lists.ardour.org>
> Sent: 18 July 2007 05:46
> Subject: Re: [ardour-users] 48 channels on ardour
>
>
> > Well I can tell you what I am running.
> >
> > Currently:(Hopefully to be upgraded soon) a
> >
> > 1.6 GHz Opteron N-Force 4 Chipset(One of the few that didn't have
> problems
> > with PCI-E and audio)
> > 1 Gig of Ram.
> > RME HDSP 9632 Interface
> > GeForce 6600 PCI-E
> > Assorted HDs(All 7200 RPM):
> >   1 200 gig system drive SATA
> >   1 200 gig playback(At the moment) IDE
> >   And whatever else I might dig up as the need arises;)
> >
> > As you can see, my computer is not that much larger spec'd than  yours.
> > What primarily is going to make the difference is having a decent set up
> > system (On Linux a Realtime Kernel etc.) and HD availiability.  Running
> > Playback/Record/ and your System off one HD will kill your performance
> > VERY
> > fast.  Try to get your System on One HD and your audio on another as a
> > minimum, 2 HDs would be better, one for recording to, one for playback,
> if
> > you do tracking a lot.  RAID arrays aren't really a bad idea either if
> you
> > have the drives, though obviously, as you can see from my specs, not
> > absolutely necessary.
> >
> > If you are in Ardour, if the problem is your HD performance, it will
> tell
> > you.  A warning message will pop up saying your HD was unable to keep
> up.
> > If your problem is xruns(dropouts) and playback continues, chances are
> > your
> > problem could be solved by ensuring you have realtime capabilities as
> that
> > user, as otherwise what can happen is an interrupt triggered by other
> > software will override your audio, and then you will drain your buffer
> > before your audio gets a chance to work again.  That is what realtime
> > preemption helps with, your audio card and software will preempt other
> > software as needed.  Or at least that is my understanding;)
> >
> >         Seablade
> >
> > On 7/17/07, John Emmas <johne53 at tiscali.co.uk> wrote:
> >>
> >> I'd be interested to know what hardware you guys are running to get
> >> 24 & 48 channels.  To be honest, my copy of Ardour often struggles to
> >> play just 4 channels simultaneously.
> >>
> >> "Struggles" is probably an exaggeration but I do get occasional
> glitches
> >> such as a short 'hole' in the sound or an occasional 'skip'.  I've
> never
> >> timed how often these happen but I doubt that I could replay 10 whole
> >> minutes of audio without encountering at least 1 glitch.
> >>
> >> My hardware is pretty old but not unrespectable.  I have a 1.2GHzAthlon
> >> with 512MB of RAM, but my disks are just standard EIDE types (though
> >> reasonably fast).  I'm running OpenSuse 10.2 with Jacklab and an RME
> >> HDSP9632 sound card.  Enough to run 4 x simultaneous channels without
> >> encountering problems, I'd have thought.  Maybe I need to tweak
> >> something??
> >>
> >> Just out of interest, what is considered a 'minimum spec' for say, a 24
> >> channel system?
> >>
> >> John
> >>
> >>
> >>
> >> ----- Original Message -----
> >> From: "John Rigg" <au at sound-man.co.uk>
> >> To: "Kevin Cosgrove" < kevinc at doink.com>
> >> Cc: <ardour-users at lists.ardour.org>
> >> Sent: 17 July 2007 23:04
> >> Subject: Re: [ardour-users] 48 channels on ardour
> >>
> >>
> >> > On Tue, Jul 17, 2007 at 02:17:44PM -0700, Kevin Cosgrove wrote:
> >> >>
> >> >> On 17 July 2007 at 20:04, John Rigg < au at sound-man.co.uk> wrote:
> >> >>
> >> >> > Yep. You'd have to decide if you really need to use 96kHz rather
> >> >> > than 48kHz. With something like a Delta 1010, most of the
> potential
> >> >> > increase in quality at 96kHz is wiped out by the increased clock
> >> >> > jitter, so it isn't really worth using more than 48kHz with that
> >> >> > particular hardware.
> >> >>
> >> >> Very interesting.  Is there much additional jitter from trying to
> >> >> sync multiple units, or is the internal jitter of one unit enough to
> >> >> degrade the quality?  How are you determining the quality
> differences
> >> >> between 48kHz and 96kHz?  Are you looking at the noise floor?  Or,
> >> >> maybe you've run a test like "effective bits"?  See
> >> >>
> >>
> http://www2.tek.com/cmswpt/tidetails.lotr?ct=TI&cs=Application+Note&ci=4405&lc=EN&from=rss
> >> >
> >> > I haven't done extensive comparisons between 48kHz and 96kHz,
> >> > but I didn't hear enough of a difference between them to justify
> >> > doubling the disk bandwidth and space.
> >> >
> >> > The Delta 1010 does have a jittery clock implementation. That's what
> >> > happens when the clock is on the PCI card and the converters are at
> >> > the other end of a 3m cable, with HF losses and crosstalk with all
> >> > the other signals in the cable contributing to jitter. I got a
> >> > noticeable improvement in audio quality just by replacing the 3m
> >> > host cables with 1m ones.
> >> >
> >> > Regarding jitter when syncing, the 1010s sound better when using
> >> internal
> >> > clock than when synced via either BNC or S/PDIF. If I don't need more
>
> >> > than eight channels (eg. when overdubbing) I run jackd with only one
> >> > Delta 1010, set to internal clock. This situation can't be completely
> >> > remedied by using a high quality external clock, because jitter
> occurs
> >> > in the cable and the Delta 1010 hasn't got very good jitter
> attenuation
> >> > on its S/PDIF or wordclock inputs. It can be minimised by syncing
> with
> >> > very short, well-shielded cables with low capacitance.
> >> >
> >> >>
> >> >> > Yes. At least one user on these lists is using it for 64 channels.
> >> >> > I'm currently using three Delta 1010s for 24 tracks. It's reliable
>
> >> >> > and I don't get xruns (I use large period size and monitor from
> the
> >> >> > 1010s' hardware outputs for `zero latency' monitoring though).
> >> >> > Having
> >> >> > said that,
> >> >>
> >> >> Are you sync'ing your three via the BNC sync connectors or through
> >> >> the S/PDIFs?
> >> >
> >> > When using all three 1010s I clock them from an Audiophile 2496 card
> >> > (also ice1712) in the same box, via a home-made 3-way S/PDIF
> splitter.
> >> > That way all three 1010s receive their clock signals at the same
> time.
> >> > As a bonus the 2496 also bumps the 1010s off the IRQ that is shared
> by
> >> the
> >> > graphics and network adaptors onto individual IRQs of their own. I'm
> >> > not
> >> > using the 2496 for I/O in this configuration.
> >> >
> >> > This is getting a little OT, but feel free to email me off list if
> you
> >> > have more 1010-specific questions.
> >> >
> >> > John
> >> > _______________________________________________
> >> > ardour-users mailing list
> >> > ardour-users at lists.ardour.org
> >> > http://lists.ardour.org/listinfo.cgi/ardour-users-ardour.org
> >> _______________________________________________
> >> ardour-users mailing list
> >> ardour-users at lists.ardour.org
> >> http://lists.ardour.org/listinfo.cgi/ardour-users-ardour.org
> >>
> >
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