How can I stream audio to multiple computers at the same time?
Solution 1:
You can combine AirPlay in iTunes 11 and up with something like AirSever to accomplish this with good results and very little effort. (Note: For more options on how to turn your Mac in to an AirPlay receiver please see: Can I use a Mac Mini as an Airplay audio receiver?)
Install the AirPlay receiver software of your choice on the machine you want to stream audio to.
Start iTunes on the machine you want to stream audio from. In the upper left hand corner of iTunes, right next to the volume slider, you'll see the output device selection icon. It looks like this:
Press it and select the "Multiple" tab at the top of the screen. Select both "Computer" (which is the computer you're running iTunes on) and the name AirServer machine from the list.
Play something in iTunes and should play, simultaneously, on both machines.
Solution 2:
I've been using Airfoil to do this for years. Only one Mac needs to have the music: it is streamed across the network to the other. You need a reasonably well performing network for this to work well: sometimes my WiFi plays up and the audio can get a little out of sync as a result. For me, it works best when using their software on both Macs (Airfoil on one, Airfoil Speakers on the other). There is a small delay when you press play before the music starts, to enable a buffer to be built up.
Solution 3:
You can use VLC (free, open source, cross-platform): it has a feature to stream music/video across your local network, thereby allowing to be used to stream audio to multiple computers at the same time.
Guide:
Download VLC media player
Install VLC on each computer you plan on streaming to or from.
Open VLC on the main computer (the computer which has the files you want to stream). This computer will control all the streaming and file playing.
Click File, then Wizard. Select Stream to Network, then click next.
On the input screen you can either use what is currently in the playlist or a saved file. You can select music files, video files, discs, or even playlists. I chose to use a playlist.
- On the streaming screen select RTP Multicast. Next fill in the address you will be using. I used 239.255.100.100. Click next.
On the Encapsulation format use whatever is already selected, and then proceed to the next screen.
On Additional Streaming Options in the Time-to-Live option put the number of how many routers you have. For example I have two routers, one wired, and one wireless so I would put 2 in.
Click Finish to start streaming. Note you will not hear the file playing, because we need to connect to the stream, which is the next step.
Open another instance of VLC. (You can do this on the same computer or different one.)
Click File, Open Network Stream, and then choose UDP/RTP Multicast. Enter the address from step #6 (239.255.100.100) and leave the port numbers alone. Click Ok and then you should hear/see the music/video being played (may take a few seconds). Do this step for each computer that wants to watch/listen.