Help with business speaker system

[SLK]

Hey guys,
I'm a very newbie to audio. I have a quick question that you all can probably point me into the right direction. I purchased a business that has roughly 8 speakers set into the ceiling. There are speakers placed throughout different rooms. I would like to power them and do not know what I really need. I would like some kind of bluetooth option or play off my phone. The speaker wires are like lamp cords and old but should still work. I'm on a budget. The guy at Best Buy mentioned getting a Sonos system? What are you thoughts? Thanks in advance.

 

[Think]

What type of speakers? Any brand / type?
Are they connected to an amp? which?

Based on your info so far, just a bluetooth receiver with line out might be enough.

 

[SLK]

I do not know the brand name. I'm guessing they were put in at least 15yrs ago. They do work and I have listened to them but the prior amp failed and the prior owners took it with them. No amp at this time. I have contacted the prior owner and he has been no help (not that he is not willing he just does not know). I can not see a brand as they are in the ceiling and just have the cover over them. I can try to get the brand but I will not be able to until Wednesday. Thanks for the reply.

 

[turk 182]

look for and see if there's a small transformer with the speaker that would mean it's a 70v line implementation.

 

[MAAC0]

If You keep the wires short You can make a series / parallel arrangement and power them from a conventional amp. Usually 70V line speakers also have 8 or 4 Ohm taps. I would use a small mini HI-FI system instead of the phone.

 

[turk 182]

70v lines driven by phones?? that seems to be a misnomer but i may be misunderstanding?

 

[pcan]

If you already listened to the speakers and you are confident that they work and are OK for your needs, then buy a mono (1 channel) PA amplifier. Add to the shopping list a bluetooth receiver with RCA line outputs, if the amplifier does not have this function already, and a cable to connect the receiver to one of the amplifier inputs. There is currently a flood of dirt cheap preowned amplifiers of this kind on the market, because they are being replaced with digital systems such as the Sonos that the Best Buy sales guy mentioned to you. The PA amplifier does have several speaker terminals; they are usually labelled C (common) - 2 - 4 - 8 - 16 - 70V - 100V. Get a multimeter and measure the resistence between the two speakers wires that had been connected to the missing amplifier. Connect the first wire to the Common terminal of the amplifier, and the second wire to the 2, 4, 8 or 16 ohm terminal according to the meter reading. If the meter does measure more than 16 ohms, the system is probably a 70V or maybe 100V one. Try the 70V terminal. Keep the volume at minimum and turn on. Carefully turn the volume control on the amplifier. If you hear distortion or noises, turn off the amplifer immediately and check the connections.

 

[OrbitalLex]

There is an app for Android called Shout, another for iPhone called Microphone. Both are Bluetooth capable. If you have a receiver that will power the speakers, you can pickup a Bluetooth receiver that will plug into your receiver amp to achieve what you are after for about $10. If you need to buy an amp, then you may as well get on with integrated Bluetooth. The Yamaha R-S202 can be picked up for about $60 or so used and has all the functionality you need. If you have have 8 speakers and assuming they are all 8 ohms, that receiver has 4x 8ohm minimum outputs. Wire 2 8ohm speakers in series for 16 ohms and send each speaker pair to one if the outputs on the receiver. Plenty of speaker wiring diagrams online. Sounds daunting, but it's super easy. Just check the speakers for impedance. If your speakers do have line transformers, they are quite easy to bypass. There are many ways to skin a cat.

Amazon.com: Golvery Bluetooth Receiver (Advanced Bluetooth 4.2, A2DP) - Portable Wireless Audio Adapter with 3.5 mm Jack - Enjoy HiFi Music for Home Audio Streaming or Car Kits Stereo System: Electronics

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Koch Blog - Koch Amps

 

[JMFahey]

**HOW** did you listen to them?

WHAT amplifier was driving them?

WHAT was the sound source used?

Basic questions which must be answered before even talking Phones, Bluetooth, etc.

By your description it is clearly a wired installation, most probably using line transformers , second possibility being some clever series parallel arrangement, but WE DON´T KNOW.

As extra data, partially remove one speaker (no need to disconnect it) and take a couple pictures, showing any codes printed on them and whether they have a small transformer attached or wired in or not.

Also find where did the old amplifier live: any wires reaching that point?
Any labels, notes, whatever?

@ pcan: agree with most of your post, which is very accurate, except on this little detail:

If the meter does measure more than 16 ohms, the system is probably a 70V or maybe 100V one.

A regular meter does not measure impedance but DC resistance.
The DCR of half a dozen Line Transformers in parallel will be quite low, in any case way lower than nominal impedance ... just like in any Audio transformer.

Meaning a DCR check can´t be trusted on its own when using Line transformers in an installation.

 

[pcan]

You are right. I had a chance to measure a string of 10 speakers on a 100V system today, and the reading from the ohmeter was less than 8 ohms.