Trouble with planet ccrma?

Trying to upgrade my system with yum, and including the planetupdates
repo, I get the message:
	Cannot retrieve repository metadata (repomd.xml) for repository: planetupdates. 
	Please verify its path and try again
And, in fact, the directory:
	http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/10/x86_64/
does not contain the subdirectory:
	repodata/
as (I suppose) it ought to.

Has anyone else seen this problem?  Does anyone know a solution?

Thanks - jon

netjack over the internet and minimizing bandwidth

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Re: Trouble with planet ccrma?

On Mon, 2009-02-02 at 13:39 -0800, Jonathan Ryshpan wrote:
> Trying to upgrade my system with yum, and including the planetupdates
> repo, I get the message:
> 	Cannot retrieve repository metadata (repomd.xml) for repository: planetupdates. 
> 	Please verify its path and try again
> And, in fact, the directory:
> 	http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/10/x86_64/
> does not contain the subdirectory:
> 	repodata/
> as (I suppose) it ought to.
> 
> Has anyone else seen this problem?  Does anyone know a solution?

(would be better to post this to the Planet CCRMA list)

Just use the normal Fedora update mirror system. Due to lack of disk
space I can't carry all mirrors at this time. You can disable the
planetupdates mirror by editing /etc/yum.repos.d/planetccrma.repo (I
thought I had disabled it by default...). 

-- Fernando

recording a sine wave with jack

Hallo,

I have a question to you. I want to record a sine wave (grid voltage) with a 
soundcard using JACK and RtAudio. I start jackd as root with realtime option 
and my record program as root too. But I get some kind of cutt-offs, which I 
attached to this mail. Can I get rid of them with some options of jackd? I 
started using JACK because I got this cutt-offs using RtAudio with ALSA, but 
now I have them again. Do you have any ideas? Is JACK the right program to 
record  measure values, or is the idea to use a soundcard for recording 
measure data a wrong one?

Thank you, steffi
  

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Re: recording a sine wave with jack

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Re: recording a sine wave with jack

Thank you for the quick answer,
I work with a sine wave generator, so it should make a perfect sine wave.
Jack prints:
delay of 221446.000 usecs exceeds estimated spare time of 11292.000: 
restart ...

I called it with:
jackd -R -d alsa --device hw:1 -r 44100 -p 512 -n 100
so I think the buffer is quiet big...
Regards, steffi

On Wednesday 04 February 2009 18:24, you wrote:
> Hi,
>
> Doing such measurements with an audio card sounds perfectly reasonable and
> should work just fine. Done it lots of times..
>
> The cutoffs you are experience do look like some kind of overrun, does jack
> print any errors? xrun ?
> overruns basically happen when the software is unable to keep up. but since
> you were running with realtime settings that is probably not the issue.
> Since you got the error both with jack and alsa I would dig deeper.
> - Some soundcards dislike some samplerates (most intel cards are only happy
> with 48khz), which can cause xruns.
> - The hardware might be faulty, causing all sorts of problems...
>
> Using bigger buffers might be a solution since you probably don't care
> about latency.
>
> Regards,
> Robert
>
>
> 2009/2/4 UfE - Stefanie Schmidt <stefanie.schmidt <at> ufegmbh.de>
>
> > Hallo,
> >
> > I have a question to you. I want to record a sine wave (grid voltage)
> > with a
> > soundcard using JACK and RtAudio. I start jackd as root with realtime
> > option
> > and my record program as root too. But I get some kind of cutt-offs,
> > which I
> > attached to this mail. Can I get rid of them with some options of jackd?
> > I started using JACK because I got this cutt-offs using RtAudio with
> > ALSA, but
> > now I have them again. Do you have any ideas? Is JACK the right program
> > to record  measure values, or is the idea to use a soundcard for
> > recording measure data a wrong one?
> >
> > Thank you, steffi
> >
> >
> > _______________________________________________
> > Jack-Devel mailing list
> > Jack-Devel <at> lists.jackaudio.org
> > http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org

-- 
---------------------------------------------------
Stefanie Schmidt
stefanie.schmidt <at> ufegmbh.de
Entwicklungszentrum Lübeck: 
Telefon: +49(0)451-3002705  
Fax:     +49(0)451-3080094 
UfE GmbH, Kanalstraße 70, 23552 Lübeck
---------------------------------------------------
Hauptgeschäftsstelle: 
post <at> UfEGmbH.de, www.UfEGmbH.de 
Telefon: +49(0)381 40597-05  
Fax:     +49(0)381 40597-03 
UfE GmbH, Joachim-Jungius-Str. 9, D-18059 Rostock
---------------------------------------------------  
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Re: recording a sine wave with jack

UfE - Stefanie Schmidt wrote:
> Thank you for the quick answer,
> I work with a sine wave generator, so it should make a perfect sine wave.
> Jack prints:
> delay of 221446.000 usecs exceeds estimated spare time of 11292.000: 
> restart ...

yes, that is a sure sign that something is wrong. such an excession
should correspond to the first fault in the image you posted (at around
t=197ms).
but i'm really confused about the fault at t=209ms... obviously, at the
first fault, data was irretrievably lost, and the entire chunk between
the two faults is late. but how would the measurement "resync" to
reality at fault 2?

i'd really be curious to hear a hypothesis...

> I called it with:
> jackd -R -d alsa --device hw:1 -r 44100 -p 512 -n 100
> so I think the buffer is quiet big...

wooops. values in the range of [2,4] are common for -n. with 100, you
might be triggering obscure bugs. i don't really know if there are
dragons there, but i'm pretty sure such values don't get a lot of
testing. i'm not a jack developer, maybe someone else is more qualified
to comment.

if you want to max out buffers, use -p 4096 -n 3 or 4.

btw: what kind of device do you use as a voltage divider? is it a lab
setup or something safe enough to be used in the field (and possibly by
an apprentice)? i'd really like to do the same to teach our apprentice
about harmonics on the grid, but i don't like the idea of him fooling
around with lab equipment under hazardous voltages...

best,

jörn

--

-- 
Jörn Nettingsmeier

Verantwortlicher für Veranstaltungstechnik

Audio and event engineer
Ambisonic surround recordings

nettings <at> stackingdwarves.net
+49 177 7937487

As for our common defense, we reject as false the choice between
our safety and our ideals. - Barack Hussein Obama
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Re: recording a sine wave with jack

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Re: recording a sine wave with jack

On Wed, Feb 04, 2009 at 08:19:07PM +0100, UfE - Stefanie Schmidt wrote:

> I work with a sine wave generator, so it should make a perfect sine wave.
> Jack prints:
> delay of 221446.000 usecs exceeds estimated spare time of 11292.000: 
> restart ...

Mmm, that indicates some trouble with one of
the Jack clients. What are you using as the
recorder ?

> I called it with:
> jackd -R -d alsa --device hw:1 -r 44100 -p 512 -n 100
> so I think the buffer is quiet big...

A bit too big maybe - I wonder which hardware would
support -p 512 -n 100...

Normal values for -n are 2 or 3, there is usually
no reason at all to go above that. For measuring,
the latency doesn't matter so you can increas the
-p value -p 1024 -n 3 would be very typical. 

Finally, on any recent Linux distro it should
not be necessary to run Jack or any client as
root. 

What you need is in /etc/security/limits.conf
something similar to:

 <at> audio		-	rtprio		99
 <at> audio		-	memlock		500000

which (in this example) allows any member of the
'audio' group to run real-time processes, and to
lock memory up to 500M. Make yourself a member
of the audio group, and there's no more need to
do anything as root.

Ciao,

--

-- 
FA

Laboratorio di Acustica ed Elettroacustica
Parma, Italia

O tu, che porte, correndo si ?
E guerra e morte !

Re: recording a sine wave with jack

Hi

> btw: what kind of device do you use as a voltage divider? is it a lab
> setup or something safe enough to be used in the field (and possibly by
> an apprentice)? i'd really like to do the same to teach our apprentice
> about harmonics on the grid, but i don't like the idea of him fooling
> around with lab equipment under hazardous voltages...

The only truly "safe" way of doing this is to connect the output of a mains
transformer to the soundcard's input.  The transformer completely isolates
the mains from the soundcard and as a result prevents any chance of
electrocution.  Of course you have to make sure that the mains terminals of
the transformer have been adequately insulated.

The only trick is to make sure the output voltage is small enough so as to
not cause clipping in the soundcard.  Most commonly available transformers
give peak output voltages of 5V and above, which is far too high.  Therefore
you most likely will also need a resistive divider on the output of the
transformer.  Since you're not after absolute voltage measurements, any old
divider should do so long as it reduces the transformer's voltage to one
which the sound card can cope with.  For example, something of the order of
10:1 divider would be fine for a transformer with a 5V peak-peak output.  A
series chain consisting of a 10K and 1K resistor (with the soundcard
connected across the 1K) gives 11:1 which would be close enough.

Technically it is true that the mains transformer will add some
"colouration" to the waveform.  However, I doubt the magnitude of the
colouration will matter for your stated purpose.  But in any case,
transformer isolation is really the only truly safe way of doing this.

It should also be emphasised that the transformer needs to be a *mains*
transformer - that is, one designed to be connected to the 110V/240V AC
mains to produce a smaller AC voltage.  They are readily available from
hobbiest electronics shops (eg: Jaycar here in Australia).  "Audio"
transformers won't do as they aren't in general rated for the voltages
concerned, nor are their isolation specifications sufficient to ensure one's
safety.

If you constructed something comprising a transformer and resistive divider
and housed it in a suitable case (thus preventing any accidental contact
with mains voltages) I think it's entirely possible (and safe) for you - or
even "untrained" novices (for want of a better term) - to use such a thing
in the field.

Regards
  jonathan