Build a Multi-Output MP3 Server?

z80 asks: "I'm rebuilding my house and I am thinking about fitting speakers in every room of the house and pulling some massive amount of cables in the walls. I also want to control and send the output to each set of speakers from the same source, and was thinking that a PC, with 4-6 soundcards, would do the trick, and there are of course a couple of questions I have. What kind of hardware would be required to be able to stream up to six different MP3's through six soundcards at the same time ? Can it even be done? What kind of software can be used to do it? Which OS? How can it be remotely controlled? With respect to the last question, I'm thinking about mounting a couple of flat displays around the house connected to old PC's that run some sort of connection (VNC maybe) to the mp3 server." This is a topic Ask Slashdot tackled three years ago. Now, with applications like Ardour showing off the power of Open Source frameworks like JACK, it seems like building such a machine might not be as hard as it once was. For those of you who have managed to build something like this, what did you do and what hurdles did you have to navigate before things were working? How would you set up a machine to run independent audio to 4 or more rooms?

Comments

Easy way to get multiple outputs

[Qzukk]

One of the side effects of not having commercial drivers and applications that use the features is that you can usually get at least two channels off of a 5.1 soundcard. The front pair of speakers and the rear pair of speakers are generally treated as seperate DSPs by the audio driver. Look around for audio drivers that treat the cards this way, and when you find one get 3 cards for a total of 6 outputs. (You're looking for a card thats supported in linux, but not too-well supported. Don't forget to check alsa's list of cards)

After that, just figure out how you're going to get the controls to work.

Existing Projects

[euphline]

Last time I got to thinking about this, I spent an evening or two googling and found:

• Ethernut Mp3 Add-On
  
• Slimp3
  

The Ethernut is more for a doityourselfer, the Slimp3 is existing product. They operate over ethernet which is not quite within scope for the abovementioned project, but might meet the same goals.

I haven't gotten around to either of these yet, but the Slimp3 in particular sounds quite cool.

-jbn

Save your money. Give a 486 a job...

[BigBlockMopar]

you could network tablet PC's to it and use wireless speakers, that would work

Sure, if you've got more money than brains, you could do that.

But if you're going to wireless speakers (which invariably suck because there's another stage of conversion or modulation, then transmission, then demodulation), you could simply use centrally-located older machines (ie. cheap) and use wireless keyboards or other means to remote control them.

Lots of the solutions under consideration seem to involve having VNC hosts and other junk like that. Why? I don't get it. Here's how this former professional audio technician would do it:

• Use notebook computers. Old 486 and Pentium-class systems with sound cards are basically worthless, will play MP3 and Ogg just fine, and can be networked easily to a central file server. Command line (ie. "I wrote my own shell which does nothing but play MP3s entirely with Perl") or GUI-driven media players should work depending on the hardware available.
• Use old desktops. We're throwing away PIII-600s at my work, but a 486 or better with an ISA sound card will be fine. Grab a multiline LCD display and hack it into a drive bay with a few pushbuttons. Put it onto your entertainment rack between the VCR and the CD player.

Remember, sound quality is dependent on the electronic quality of the sound card you're using, not on the CPU speed of the processor. Generally, if it can play an MP3 without skipping, it's fast enough. DO look for *old* Creative Labs 16-bit ISA sound cards where the output amplifiers are in 8 pin DIP packages with "LM741" on them; in under 10 minutes you can bring them to almost the sound quality of the finest $2000 CD players.

And don't do stupid things that say "I think car audio is KEWL" and run unbalanced line-level audio all over the house unnecessarily. Run Cat-5 all over the house; run the sound card outputs to the amplifier as neatly and as shortly as possible in each room.

If you do it that way and have a good quality stereo system (ie. the speakers are actually made of wood and the amp claims it's only 50W but seems to weigh over 75lbs anyway), your fidelity will be limited mostly by the quality of the MP3s you're playing.