Syncing audio across multiple PCs

July 2, 2007 9:04 AM

Two PCs. Two stereos. How to get them to play the same mp3s at the same time?

There's a stereo in the front of my house, hooked up to a PC running iTunes or some other mp3 playing software. There's a PC in the back of the house, also hooked up to a PC with iTunes or similar. The PCs are on the same Ethernet network. I'd like to use one of the PCs as a "front end" where I can manage the song queue, and have both PCs/stereos play the song a tthe exact same time, without any lag issues. Is there software that can do this?

posted by skwm to Technology (17 answers total)

Response by poster: Note that the audio on the front of the house will be somewhat audible in the back of the house (and vice-versa), so they need to perfectly synced.
posted by skwm at 9:06 AM on July 2, 2007

There's no way you can "perfectly sync" them. The only way to do what you want is two-stereos-one-PC, by running the audio line from one PC to both stereos.

Any approach involving two computers will always result in a small difference in synchronization -- and even if it's only 50 milliseconds, you'll easily be able to hear it. (It would probably drive you nuts.)
posted by Steven C. Den Beste at 9:25 AM on July 2, 2007

Buy an apple Airport Express, use it to drive the back end PC's speakers (has a plug for this purpose), select multiple speakers within itunes. This is how I use my main PC in the office to drive the living room and back yard speakers. A couple of Airport express boxes on the wireless (or wired) network gets the job done.
posted by iamabot at 9:29 AM on July 2, 2007

I agree. A better solution is to pick up a pair of wireless speakers and run your music from just one PC.
posted by pencroft at 9:30 AM on July 2, 2007

Perfectly synced through some sort of software running on 2 PC's? I can't think of any easy solution that way. You might consider Airport Express units with AirTunes, and controlling them both from one PC. iTunes will see the AE units as remote speakers in iTunes, and link them to one running instance. You could probably set them up to be operable from either PC, but I think trying to sync processing power of 2 whole PC's is going to be a major PITA.
posted by pupdog at 9:30 AM on July 2, 2007

It'd probably be easier and cheaper to set up a microbroadcast station from your computer (within FCC guidelines for personal use) and broadcast it over FM so that you could listen from any room in the house.

AFAIK, even streaming over your internal network will have lag issues.
posted by SpecialK at 9:35 AM on July 2, 2007

2nding what iamabot said. I have an Airport Express into which two old bigass (floortop) speakers in the living room are plugged in. I have two small speakers attached to my laptop in my home office. I play music through both with iTunes. There's no lag between them, fwiw.
posted by derMax at 9:35 AM on July 2, 2007

Best answer: Play around with the streaming features of VideoLAN, which was originally a project to do just the sort of thing you're asking after -- except with video, too. They've rolled a bunch of the server features into VLC itself.
posted by majick at 9:41 AM on July 2, 2007

Best answer: Put Slimserver on the PC with the music library. Run Softsqueeze on each PC, checking the option in Slimserver to play in sync mode.

I don't know if the songs will be perfectly synced. It will be very close. Also, it is free to try and requires no new hardware. The times I have done this, the synchronization sounded perfect.

If you like it, you can buy the hardware Squeezebox and eliminate the need for the second PC.
posted by Uncle Jimmy at 9:43 AM on July 2, 2007

I can confirm the Squeezebox hardware synchronization is truly in sync. I regularly play music in my house from two different stereos simultaneously, and I can hear both. No annoying delay.

It may not work as well in the software emulator. But it can't hurt to try!
posted by Nelson at 9:56 AM on July 2, 2007

I believe that the Slimserver system re-syncs at the beginning of each track, so the shorter the track, the better (i.e. 4-6 min pop/rock songs sync a little better than 30 min classical pieces).
posted by Nice Guy Mike at 10:21 AM on July 2, 2007

1) Run Shoutcast on PC 1.

2) Run Winamp Lite or similar no-nonsense player on PC 1 and PC 2 and have it play the stream from PC 1. Disable or minimize buffering.

Let us know how it works out.
posted by zippy at 10:41 AM on July 2, 2007

Another vote for Airport Express. Mine sync flawlessly.
posted by kableh at 11:29 AM on July 2, 2007

This is a toughie because a lot of packet based streaming might toss in some delay. I would buy a fm transmitter, tune the stereos to 87.9 or whatever, and plug it into one PC.
posted by damn dirty ape at 11:37 AM on July 2, 2007

Low tech - Speaker wire plus a Y adapter?

High tech - Media Center will let you define "Zones", where playback of different playlists or smartlists is allocated individally from a single PC. Usually, "Zones" correspond to different rooms, where you want different music streaming from a central server. In this case, you'd make both Zones overlap I guess, and route the same output to both.
posted by meehawl at 12:46 PM on July 2, 2007

My solution has an mp3 player feeding into a cheapo FM transmitter, after which any stereo in the house (or indeed throughout most of the block) can hear the music on a previously 'dead' station. This is legal, provided you use an FM transmitter with a low enough output, i.e. the kind you can buy at Frys or even RadioShack.
posted by foobario at 3:27 PM on July 2, 2007

Just use the VLC like so: stream output using UDP to a multicast IP address (224.0.0.0 to 239.255.255.255 are designated as multicast addresses, port is irrelevant) from one VLC on the host and playback from a second VLC on the host and a VLC on the remote machine. You might want to reencode the audio and video by checking the video and audio codec boxes on the Streaming pane of VLC to ensure that the stream is relatively consistent across inputs. Here are screenshots detailing the process roughly.

The version of VLC must be equal otherwise you're going to have trouble keeping synced. You need to start the host first or it will act strange. You might have to stop and restart the host once you have the clients running in order to sync fully and after a long period of play they might drift a little. I've had this configuration working across Win/Mac platforms in a lab of 30 machines before, pretty neat. I've also played DVDs across the lab this way.
posted by thadk at 5:32 PM on July 2, 2007 [1 favorite]