Install auto on/off relay inside active speaker

[okcorrell]

Hello,

I wanted to reach out for some help to some seasoned DIY audio people.

I have several 5" Monoprice powered monitors paired up with apple airport express' for a makeshift multi room system. It works perfectly as each book shelf speaker is independently powered for each small room, but they are always on, even while not in use.

I have another pair of AudioEngine book shelves used as the primary audio solution for my living room and those automatically shut off when not in use, which is an amazing feature. Is there anyway to install this signal sensing relay in these Monoprice monitors I have? Does anyone make this part that I can solder in or do I have to make it myself? I would prefer installing something inside the cabinet (DC) as it would be easier and more aesthetically appealing.

I have experience in basic wiring with access to soldering tools and I am more than happy to pop the cabinets open to install this circuitry myself or to give more detailed information about the hardware I am working with.

Any leads or recommendations in where to look would be greatly appreciated.

Thanks for your help in advance.

Aaron

[JonMarsh]

As an engineer, I can tell you that this is not usually a separate function board within a product like this, but an integral part of the overall design- usually there is electronic control of bias circuits or power supply behavior, as well as a sensing system designed to switch on at some signal threshold.

I would check at DIYAUDIO.COM for possible DIY implementations, or whether there are similar kits available to the DIY market from suppliers.

[bigjohn]

I had a similar problem with an old Carver amp I had, I was too lazy to actually want to turn it on and off, I found a power conditioner that had a trigger input that would turn on certain outlets when it received a signal. A system like this could be implemented in this situation, by either buying or building.

[TEK]

When the electrican installed the power at my place he laid down a control wire. That last wire is connected to a separate light switch that cuts the power from several of my sockets (the ones that my amp and sub's are conneced to). When endring the room I turn the switch on. When leaving I turn it off.

My experience with signal sensing is from plate amp's, and not very good as they would ofte wait to long before turning on.
You might be able to use a relay like this one, http://www.ntsupply.com/files/products/AP5051CSR.pdf (in principal - not exact product), but you would also need a timer - as I assume you do not want it to turn off every time there is a slow pause in the music...

[BobEllis]

See http://sound.westhost.com/project38.htm I built one of these into an amp, with works well with the caveat that for stereo use the input buffer should be changed to an inverting configuration to prevent crosstalk. Sounds like in your application that won't be an issue. If you plan to make one for both channels, use only one channel to feed it.