fast routing (switching) of a single output to n distinct monitors


I need to route sound from a personal computer to one of a horde of monitors. Only one monitor will be active at any one time, but I need to be able to switch between monitors rapidly (<50ms) controlled by the computer.

For n <= 2 monitors, the solution is simple. The computer can output a mono signal on channel 1 or 2, amplified through a standard stereo amp. For n <= 5 speakers, likewise, with an appropriate sound card and 5.1ch amp.

But what if I need to drive one of 10 monitors, or more? Of course, I could use, say, two M-Audio Delta 1010LT PCI cards and two off-the-shelf 5.1ch amps. But that seems wasteful, and impossible for n > 24.

In particular, I was wondering: does there exist a device which can rapidly route a single amplified output to one of n different monitors -- based on an external control signal?

Matt Mizumi

Posted 2012-06-19T02:25:28.203




If you're going to do your channel switching in software, I would start looking into external hardware interfaces instead of "sound cards". The first step up is hardware interfaces that connect with USB2 or FW400, but beyond that you're actually using a PCI slot just to get the raw throughput to a DIFFERENT piece of hardware that actually handles the I/O.

For example, the MOTU 24I/O has 24 in/out channels, and interfaces with your computer through a PCI card.

The M-Audio ProFire 2626 appears to be able to do 26 channels of I/O over FireWire.

Apogee's Symphony I/O System can do up to 64 channels per card if you have two 32x32-configured I/O boxes. (For a price, of course. 64 channels: $18,365)

Depending on what you're actually doing, it might be more cost-effective to design your own solution. Simultaneous multichannel I/O is expensive, but if you're just routing a single signal to a bunch of different outputs, you might be able to push the switching itself farther down the signal chain. Of course, that option gets less and less safe for your equipment--you wouldn't want to switch between different speakers AFTER the amplifier in your signal chain.

It'd also be unsupported and likely to break. Needless to say, if Disney were designing a huge multi-channel audio experience, they'd be spending the thousands upon thousands of dollars on the monster audio interface and dedicated amplifier for each speaker.


Posted 2012-06-19T02:25:28.203

Reputation: 1 547

thanks for the insightful suggestions! since I don't need simultaneous playback, switching as far down the chain as possible seems the way to go for cost-effectiveness. anyone aware of an off-the-shelf solution for that? – None – 2012-06-21T01:47:19.987

You can google "Speaker selector" and find a few options, but you can't control them with a computer, and they're usually n < 8. They're also only safe at low-medium power levels. If you want to do this that way, you're almost certainly going to have to design and implement your own solution to have it both computer-controlled and n > 24. – None – 2012-06-21T03:17:46.703