Hello, I have a client who has is opening a salon/spa and they want to have 14 speakers throughout their building. They only need one source for music with all 14 speakers playing at the same time. They'd like to have 10 speakers have individual volume control and there will be 2 sets of pairs with each pair having volume control.
We plan on running the speakers in parallel, but my question is, is there an amp out there that can handle all 14 speakers or do I need a couple of amps and just split the source audio to the multiple amps?
Wrong approach. You want a 70v or 25v system. This is how systems like this are done. Very common.
Yup, you need an amp something like this:
http://www.bhphotovideo.com/c/product/462570-REG/Crown_Audio_CDI1000_CDi_1000_Solid_State.html
Click the "Specs" tab, it will drive a 70V system directly. Crown amps have been offering a great price/quality combination lately. There are many others. If budget drives the project, you can check out TOA, but I don't recommend them very often because the quality isn't there. QSC makes excellent 70V amps that will run for many years, you do pay up a bit though.
Each speaker will have a transformer, you select taps on the transformer for the maximum power you want to that speaker. Speakers are sold with transformers included and mounted.
As others stated, you can simply daisy-chain wire each speaker as needed. Because you distribute 70V, wire can be lighter than low Z systems, 18ga is just fine.
It also sounds like you're thinking stereo pairs. Just forget that, it's not worth the trouble. Use your many speakers to cover the area evenly with a mono source. Imagine each speaker covers area like a can light would. Space them no farther apart than the are high above the typical ear, you'll be good.
Your local volume controls would be like these:
http://www.mcmelectronics.com/product/ATLAS-SOUND-AT100-/555-7342
Commercial grade power amps don't offer much in terms of input selection or control. Some have volume controls, but that's it. You might want a small mixer feeding the amp as a control and input selection device.
You could do a series/parallel scheme to keep the load above 4 ohms but it would be a complex wiring job and difficult to maintain. And local speaker control would complicate things further.
I would take one step farther: don't even consider it as a possibility. Commercial 70V systems are the way to win.
