Hello,

I'm doing an pretty basic install in my friend's movie theatre. I need to run two ceiling speakers into the lobby.

The amplifier is upstairs, which will be left at a reasonably high level, then I'd like the staff at the concession stand to be able to reduce that volume with a volume knob downstairs.

Trying to think of simplicity (mounting in a standard electrical box) and price, could I use a standard lighting rotary dimmer switch/knob to adjust the volume of the speakers? (I know it won't amplify, it will only attenuate).

It's the same principle, right? But I'm not sure since they are designed for higher voltage/amperage if it will cause any problems.

Thanks for your help.

What you need is available at Radio Shack. It allows you to lower the volume without changing the impedance. A dimmer will most likely overload the amplifier and create a possible failure of the equipment

Hi Missouri Bound,

Thanks for your answer. I figured that there might be some sort of issue with impedance, just wasn't sure how. I actually just stopped by a RadioShack and saw what I think you are talking about - that's probably the route I'll go. Not to mention it mounts nicely with the wall plate and everything.

Thanks for your help!

What you need is called an L-Pad. You can find them online. You will need it to be the appropriate wattage and voltage for your amplifier.

A dimmer switch will not work. I worry about you doing an install in a commercial environment if you do not know the difference between a dimmer and an L-Pad.

I forgot to mention, it also needs to be matched to the impedance of the amplifier.

So, we need to know the wattage and impedance of your amplifier, and if it is a standard (25v) or 70v system.

In case you're not aware, the combined imedance of ALL the speakers on the same amplifier channel must match the impedance of your amp.

l-pad - Google Product Search

ceilingfanrepair,

That's why I asked first. So I don't do something stupid :) Just trying to help a friend out. I do television engineering for a living, not sound stuff - though I'm trying to increase my knowledge in that field, since it's just as important.

I do appreciate your link and information - that may be useful in future projects! But for now, I'll probably stick with the RadioShack deal, since it's pretty much an L-pad built into a nice wall plate.

Thanks for your information.

I know the one you speak of. You may be able to find it cheaper online.

Just make sure all the wattages, voltages, and impedances match up (or err in the correct direction) or you will fry something.

Ah yes, quite true. Thank you for your concern and for helping me to avoid blowing something up! Have a good night/day!