I wish to use a mac mini as a home theatre system.

I would like the mini to send commands to the power amplifier to turn on/off depending on whether there is any sound generated (like a screen saver but for sound).

Anyone have ideas on how this can be done?


Power Amp is Cambridge Azur 650R, which can be controlled by IR or RS-232.

Amp manual says not to keep on at all times, and I wish to conserve energy.

I am looking for something equivalent to the 'Sleepwatcher' utility (for the display, that I will use with my projector), but which works for sound.

I have found that the HALLab utility, from apple's XCode developer kit, can show that sound is 'Running somewhere', so it's possible in software.

Anyone know of a tool that uses this? Or which library calls I could use to do the same thing as HALLab?

  • Is this for a power amp you already own? If so, what means/interface does the amp have for turning it on/off? Provide make/model if you already own the amp. And why isn't leaving the power amp on all the time an option, does it make noise, or are you just trying to save energy? – Phil M Aug 6 '11 at 8:40
  • Did you ever find a solution to this? Also I notice Running Somewhere is Yes even if the audio playback is paused. (Which would be undesirable for my use case.) – funroll Nov 11 '14 at 19:46

I don't know of any way to react to sound output in software, but:

This could be done as a stand-alone hardware device reasonably straightforward. I didn't find any ready-made products, but it wouldn't be too hard for any electronics hobbyist with some analog experience, I think (here's a design I found, for example; it could probably also be done with a single microcontroller, especially if the amplifier has an IR remote control). Let me know if you'd like me to expand on this possibility...

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