Any audio distribution guys here?

I've been given the task of upgrading an audio system in a small office (and doing it on a smallish budget).

Currently they are using a 1960s single channel FM receiver connected to 9 ceiling mount speakers of unknown age. 3 rooms have volume controls.

the existing stereo has 1/2 the speakers on the "left" output, and the other on the "right".

Any suggestions?

Is this system for music or more of a paging system or both?

Just music.

Are the existing speakers running on 600 ohms or 70V line outs? Or is it the standard 4/8/16 Ohm for a residential style speaker output?

there are 9 of these: http://i.imgur.com/fsehunI.jpg

connected directly to this: http://i.imgur.com/nMHKNH4.jpg

Any way to figure out the impedance of the ceiling speakers? You can disconnect one and just use an ohm meter if you have one.

The real way of doing speaker distribution is running the system at a higher voltage so that the voltage drop is of a lesser percentage.

W=V^2/R

10 Watt speaker at 8 ohms is 8.9 Volts. Just dropping to 8 Volts, the wattage dropped by two watts (8 Watts).

So they run the system at 600 ohms or 70 Volts or something similar. Then you either have speakers that can take 600 ohms or whatever, or you have an 8 ohm speaker and a small transformer at every speaker.

I'd look for a Bogen PA amp, but they are a bit expensive and you'd still need a radio output. www.parts-express.com is a good place to start. I think they even have a forum and a help phone line. I've ordered from them before and couldn't complain.

Take a look at the top of one of those speakers. Do they have transformers on them?

Like this:

According to this: www.johnweeks.com/tour/pioneer/ That receiver is actually from about 1981!

Other than that I got nothing.

My first question is... if the system is working, why upgrade it?

My next question is... if there are 9 speakers, how can half of them be connected to the left output and half to the right?

But seriously, folks... to do this correctly, you should go to a 70 volt system. The cheapest 70v ceiling speakers are $25 on Parts Express. Then figure in volume controls (attenuators), an amplifier with a 70v output, and a FM tuner. You're looking at $400+ to do this the right way.

All to listen to FM radio? Again... if it ain't broke, why fix it?

If you want to run a 70v pa amp and find yourself needing those transformers for each speaker let me know; I won a box of them on eBay one time thinking I was getting a box of ten, but instead got ten boxes of ten. Since I only needed three, somewhere I have 97 extras.

The stereo is dying. Looks like they are only allowing enough for a new stereo. $300 doesn't go very far.
Tasks like this make my head hurt.

At worst, you're looking for 9 transformers, fm tuner and an amp. At best, you're looking for just an amp.

The volumes are probably a potentiometer or rheostat, just reuse them and their wiring.

If the speakers are fine, reuse them. Throw a multimeter on them and find a resistance so we can infer a impedance.

Try to find a 70v output PA amp so if you need transformers, then oldopelguy is your man! Hook them all up as 10w and start from there. If you have an area that needs to be louder use a wattage tap one step higher (15w) or just lower all the rest. It's kind of like setting the volume level for each speaker. The design guide below give more information.

100 Watt PA amp with audio imput for $160: http://www.amazon.com/Pyramid-PA305-Amplifier-Microphone-100-Watt/dp/B000NPP9R6/ref=sr_1_1?ie=UTF8&qid=1452086876&sr=8-1&keywords=pa+amp+100+watt

Design Guide: http://www.bogen.com/support/productcatalog/pdfs/sysdsgn.pdf

FM Tuner $57: http://www.amazon.com/PT504-Mount-Digital-Tuner-Feature/dp/B002UKZ9K4/ref=sr_1_3?ie=UTF8&qid=1452086693&sr=8-3&keywords=fm+tuner

If the old stereo is dying, is it the amp portion? the whole thing? the am/fm tuner part? If it's just the amp part, you might be able to skip the fm tuner component and use the pre-amp out to fee the new PA amp. What about fixing it? Does it need to have the pots and other parts cleaned with an electrical contact cleaner?

I'd also watch craigslist for Bogen amps. Churches and small business sell them from time to time.

I'm interested in this stuff but I've never set up a system so if someone is more knowledgeable, please correct/add/help.

If you just want to replace the stereo, just replace the stereo. Goodwill has old stereos that I've used before. A little contact cleaner and most work just fine.

A $300 budget is a little tight to do anything fancy. I recently did a similar project in my dad's office. They have 4 speakers, and the 90's Yamaha receiver was having a bunch of issues. Since its pretty low volume, sound quality wasn't a priority and we left the 90's radioshack speakers. He wanted to ditch the radio and use pandora.

I ended up getting him a $25 Lepai amp and upgrading the power supply for it. We have it set running in mono and it works great. We looked at going the normal Nutone route, but it was a lot of money for what it does.