[linux-audio-dev] IUPUI Student Radio Station should be based on Linux

Dan Mills dmills at spamblock.demon.co.uk
Fri Mar 11 21:45:39 EST 2005


On Friday 11 March 2005 03:03, ben racher wrote:
> Hello,
>
> I'm starting a student radio station at IUPUI in Indianapolis, Indiana
> and I want our entire audio infrastructure to be based on Linux. I've
> got a rough sense of all the apps we need and what apps to setup on
> which computers, but I thought I'd run the blueprints by you guys to see
> if you could give me any feedback.
>
> Streaming/Web Server: Runs apache and icecast or the icecast mod for
> Apache.
>
> Automation Computer: Runs some sort of playback program, I've been
> keeping my eyes on LiveSupport http://www.campware.org/ to schedule and
> automate the station when DJs aren't present.

Are you sure you only want one? It seems to me that a network system is really 
needed here as you really need:

On air playout (Two of possibly?).

Record library terminal (used for importing audio, setting segue points, talk 
timers things like that)

Log creation & scheduling.

Traffic & Reconciliation... 

And that all of these need to interact. 

Now the disclaimer: I hack on Rivendell[1] which uses exactly this model so I 
am obviously in favour!


> Audio Archive: File Server for our digital library, probably all FLAC
> files, maybe Ogg, but I think we want FLAC in case we want to burn CDs.


> And this is the part that I need help on...
>
> Production Computer... so I've been tooling around with JACK and Ardour
> and MusE (not to be confused with MuSE) and other JACK apps and its all
> really cool and exciting. I never got the sound input to even really
> work in linux until a couple weeks ago. Yay for the 2.6.8+ kernels. So
> here are my thoughts on setting up a workstation, and I don't even know
> if this is possible, but that's why I'm mailing you guys. One department
> has kindly donated a brand new Dell Poweredge Dual Xeon 2.4 ghz somethin
> or other. The rest of our computers are from the university junkyard of
> midgrade PowerPC G4s and Pentium 3s. So the Poweredge is our gem
> computer out of all the other crappy computers. Is there any way for me
> to set up the speedy new poweredge as some kind of audio production
> renderfarm, and get the PPCs and the Pentium 3s to connect to it as
> production terminals? Cause, although multi-tracking on the G4s and
> Pentium 3s is possible, doing extensive work with FX plugins is probably
> out of the question.

For the vast majority of radio production, you don't need serious 
multitracking! 
I am seeing lots of two track work with spot effects and some gain changes but 
normally not a lot of multitrack work. 

Now, you could run the DELL as a server and just hook the others up as dumb X 
terminals. Put a multichannel card (or two) in the DELL and feed audio lines 
to locations near each terminal..... However, I cannot help but feel that for 
most production for broadcast, audacity running on a a PIII 800ish should be 
just fine.  

> See what I'm getting at? Also, the Poweredge also has about a 500gb raid
> system with it, which would be nice to use for storing our audio on and
> maybe even using as our digital archive as well, but that might be
> pushing it if we are doing audio production work on it as well? 

I would put the audio and database on the poweredge and export it via NFS to 
any clients that need direct connections. Possibly run the playout engine 
here as well, and just have the clients run on the slow boxes. 

> I'd 
> imagine this might be the case, but I don't see why ftping flac files on
> a local network would be too much of a burden on the raid drive or dual
> processors.

Disk bandwidth is not that much of a problem on modern systems, but depending 
on what you are running processor load can be. You do not want anything to 
interfere with whatever is producing the audio for the transmitters! 


> Another reason why it would be nice to be able to connect to 
> a poweredge remotely to do audio work, is that it the poweredge makes
> about as much noise as a 747. So... its not exactly an audio production
> friendly unit.

Well, you will need to have a rack room anyway, so why not stick it in there? 
In fact why not put ALL the computers in there out of the way and run the 
video, mouse & keyboard cables to wherever they are required? Makes for a 
much nicer working enviroment.  

One word of advice! Word clock is your friend when doing this sort of thing! 

While jack.udp and friends can deal with moving the audio over the network, 
they do NOT deal with keeping the sound hardware in sync, either have ALL the 
audio handled by one soundcard (OK for 12 or so stereo streams), OR use 
wordclock to keep everything in sync. Failing to do this can cause much 
weirdness (Painful experience). 

HTH.

Regards, Dan.

[1] http://www.salemradiolabs.com/rivendell


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