Posted By Mike Ash on December 29th, 2005

The common audio splitter is a useful tool to have, whether you’re wiring your home stereo or watching a movie with your wife on a train. The one pictured on the right is available for $1.79 from Wholesale Electronics, Inc. But this bulky and expensive item is not always available when you need it. Today, I will show you how you can use a mere $4,000 in computer equipment and some of our very own software to duplicate its functionality.

Oh, and this could possibly be used for things like sending audio to another room. But we make no guarantees.

What You Need

To follow along with today’s tour, you will need the following items:

• Two Macs running Mac OS X 10.4 (Tiger) or, if you happen to be reading this from the future, higher.


• A reasonably fast network between them. AirPort will work. LocalTalk will not.


• A copy of Audio Hijack Pro on each Mac.


• A desire to get the most from your equipment!

Setting Up The Sender

Open Audio Hijack Pro and hijack the application or device that you want to transmit. For my example, I will use iTunes. Once iTunes is hijacked, select the Effects tab and add a new effect by clicking in the grid. Select AudioUnit Effect->Apple->AUNetSend. A new window will appear with various settings, but the defaults should do fine. At this point, your window should look something like this:

Setting Up The Receiver

On the receiving computer, we’re going to use Audio Hijack Pro solely for the Effects tab. However, in order to activate it, we still have to hijack something, so I’m going to hijack the Silence Input. Now, switch to the Effects tab and add a new effect. Select AudioUnit Effect->Apple->AUNetReceive. Its configuration window will appear, and from here, you should see the AUNetSend unit that you set up on the other computer. Click it, click “Connect”, and you should be in business.

For some reason, my AUNetSend unit showed up multiple times. I just tried each one in turn until I found one that actually connected and played audio. At this point, the receiver’s window looks like this:

Listen Carefully

And there you have it. The next time you find yourself on a train with two laptops and two pairs of headphones but no audio splitter, like I did a month ago, you can happily watch saved TV shows with your Significant Other.

Be sure to tune in next week, where we will show you how to use your PowerBook™ or Power Mac™ as a handy substitute for various common kitchen appliances.