1 scanner... how to run multiple speakers in multiple rooms

[portroyalbirdy]

A little background info on this project... I volunteer at my local EMS Station and we are putting a scanner in the day room/lounge. We have a radio/repeater combo in the room now, but we switched to a new dispatch channel, and a new tower was put up in our coverage area. Leaving that only able to monitor Med 9, and with the new channel and tower, the repeater part is no longer used. I'm donating them a BC 340 CRS so that we can monitor the new dispatch channel plus the surrounding county channels. The current coax cable is hooked up to the Motorola radio/repeater. My plan is to get a Motorola to BNC connector at my local Radioshack and use the existing cable. We are also buying an all band outdoor antenna ( SP800BNC, SPIDER BASE SCANNER ANTENNA 25-1300 MHz FULL FREQUENCY COVERAGE, ANALOG OR DIGITAL with cable and BNC connector - Scanner World - The Largest Dealer of Scanning Radios in the World) to put outside on the existing repeater tower outside our station.We want to have many speakers in the building in different rooms run off of this one scanner. Two Questions? What is the best method to do this? and can you use any speaker if you have the right jack?

 

[ofd8001]

At our fire station we ran the audio output from the scanner to an amplifier we got at Radio Shack. The output of the amplifier was then sent to multiple speakers throughout the fire station. Did a fine job.

The biggest issue was people tinkering with settings, such as locking out channels or raising/lowering the volume. So you might consider placing the scanner in a secured location and getting the kind of speakers that have individual volume adjustment. The individual volume adjustment can be helpful in that larger rooms may need more volume, but in smaller rooms not so much.

 

[portroyalbirdy]

At our fire station we ran the audio output from the scanner to an amplifier we got at Radio Shack. The output of the amplifier was then sent to multiple speakers throughout the fire station. Did a fine job.

The biggest issue was people tinkering with settings, such as locking out channels or raising/lowering the volume. So you might consider placing the scanner in a secured location and getting the kind of speakers that have individual volume adjustment. The individual volume adjustment can be helpful in that larger rooms may need more volume, but in smaller rooms not so much.

Thanks ofd8001! Can you tell me what to search on RadioShack for the amplifier?

 

[flythunderbird]

How many speakers are you wanting to run?

 

[ofd8001]

I believe it was along the lines of:
RadioShack 250W Stereo PA Amplifier : PA Amplifiers | RadioShack.com

Just your basic public address system amplifier. It's been a long while since we installed it - I imagine the model we used is no longer available.

 

[quarterwave]

A distribution amp would work well. That way you get equal power and volume controls at each drop. Such places are RS, MCM, Parts Express should have the stuff to do it.

In the Comm Shop, I used to have an amp with about 10 speakers, including outdoors setup with multiple input adjustments so we could page for phone, run background music, and our own shop radio audio over the same speakers.

(also had 5 radios, 1 scanner, fed off our tower with 3 antennae, there were 6 TSN6000 Moto speakers on my desk...what can I say...I liked to listen!)

 

[portroyalbirdy]

Probably about 8 speakers

 

[flythunderbird]

Probably about 8 speakers

I agree with quarterwave's assessment ... an 8-channel distribution amp, like this:

Nady SD-2418 Audio Signal Distributor SD-2418 B&H Photo Video

and eight speakers, each with a volume control, something like these:

Bosch LB1-UW06V-x 6W Cabinet Loudspeaker F.01U.076.906 B&H Photo

PROVANTAGE: Bogen Communications WBS8T725V Speaker Baffle Assembly

would give you what you want. You'll also need an adapter to convert the signal from the scanner to an XLR-level input for the amp:

1/4" Jack-to-A3M XLR Plug Adapter/Transformer : XLR Adapters | RadioShack.com

and the appropriate patch cable.

With respect to the Radio Shack amp, it could be used, but you'd need to insure that the total impedance of the eight speakers does not exceed the bounds of the amp(in this case, 4 ohms to 16 ohms); otherwise, amp damage may result.

 

[RC286]

8 speakers, single channel. Grab a mono PA amp. an 8/16 ohm will do, however if you can luck out and get a 70v amp for a good price, grab it.

If your using an 8/16 ohm amp, get a matching transformer rated to your total system wattage. (ex 8 speakers x 10w = 80w) to turn that low impedance amp into a high impedance 70v system. Now all you need is one feed line, and matching transformers at each speaker to convert the 70v back to the 8 ohm impedance for the driver. I have found ceiling mount w/baffle and wall mount w/enclosure speaker + transformer combo ready to go surplus for $10 each. With this setup, you can use smaller gauge wiring, and hook up many speakers to a single channel.

Take a peak at this PDF.
http://www.crownaudio.com/media/pdf/amps/138905-1_10-05_constant_voltage.pdf
There is some math in there for the impedance matching, but as long as your wattage are all within limits your pretty well good to go.

I can elaborate on this a bit more if you need.

 

[ramal121]

I'll second the above. A mono amp (don't get a stereo, that's a waste) in the 50 to 100 watt range. Many are available with 25V/70V outputs built in. Use those outputs, not the 4 or 8 ohm speaker outs.

You'll also need unbalanced line level "aux" inputs. Some models have more than one for different sources. Don't use mic inputs, it is way too easy to over drive them resulting in distorted audio.

With a 70V system you can use smaller wire and still avoid losses in long runs. Wiring is non-critical and you can daisy chain speakers or home run them.

The speakers themselves come in all types. Mostly a box wall mount or a flush mount. You'll have to make sure they are for a 70V system and have the matching transformer with them. These transformers have multiple input taps and you pick the one best suited for the location. Quiet spots like sleeping quarters and offices you can get by on the 1 watt tap. Larger day areas that need more volume can use a higher tap. 2.5, 5, and 10 watt taps are common. The rule of thumb is to add up all the taps of the speakers and be sure the total does not exceed the rating of the amp.

Speakers with individual volume controls are nice as they let you set levels throughout the building as needed and helps to keep grubby hands off the radio and PA amp.

I've seen too many in house PA systems that have been cobbled together. They sound like crap and more often than not will prematurely put a high power amp in it's grave.

http://www.parts-express.com/cat/commercial-70v-installation-amplifiers/1709
http://www.parts-express.com/cat/commercial-70v-installed-speaker-systems/3431

 

[n5ims]

My vote would also be for a 70V system since that's the job it was designed to do, feed multiple speakers throughout a building and allow for individual volume control for each speaker. If starting from scratch (and it isn't that much extra work), I'd make each speaker run go all the way back to the amp instead of daisy-chaining them. This will allow you to make changes later if you need to do so. Also, if a stereo amp isn't much more than a mono one is (I'm talking a PA amp with native 70V outputs, not a home stereo), having one would allow you to split things up as appropriate (e.g. sleeping quarters on one channel and other areas on the other) so you can feed them with different audio streams (perhaps audio continuous on the main feed and muted until an alert is sounded for the sleeping quarters).

 

[portroyalbirdy]

Wirelessly posted (Mozilla/5.0 (Linux; U; Android 4.1.2; en-us; SAMSUNG-SGH-I547 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30)

Thanks to everyone with their thoughts on this project! I will keep you all updated on how this goes!

 

[737mech]

network feed the scanner

How many computers in the house? Why not setup a feed to a small network then you have individual volume control no wires and speakers all over the place. Feed could go more places as needed. You could even have it at home with controlled access etc.

 

[portroyalbirdy]

How many computers in the house? Why not setup a feed to a small network then you have individual volume control no wires and speakers all over the place. Feed could go more places as needed. You could even have it at home with controlled access etc.

This will be going in my local EMS Station. And please explain your plan in greater detail.

 

[portroyalbirdy]

Hello all just a little update with this project! We have all the equipment we need and are in the process getting it all together! My question is on the amp, what do you set everything to?

 

[majoco]

SSTrans3000 AM transmitter at the scanner and AM receivers in any location you want within 200feet or so. No wiring to run. A VHF car type MP3 transmitter may interfere with the scanner reception.

 

[ScannaMan9]

I have a set of these in my home, they work pretty well. The unit you see with the phone has a retractable cord with 3.5 mm jack. I sit I to top of my desktop and run pandora throughout my home. PM me with any questions... If you would like I could shoot some video/ pics for you

Audio Unlimited SPK-VELO-003 Speaker System - Walmart.com

 

[portroyalbirdy]

I have the amplifier, I just need to know what to set it to, like bass, tremble etc.

 

[ofd8001]

I'd set everything mid-range, then "fine tune" to taste. Unfortunately I'm guessing you'll find tastes varying all across the board. (It's probably along the lines of choosing which color to paint the equipment bay - you'll get a wide variety of opinions).

 

[portroyalbirdy]

An update. The project is complete! We have a Speco Technologies amp hooked to a BC340CRS which is hooked to an Antennacraft ST2 Scanner antenna. The amp is connected to 8 in ceiling speakers The only issue I have is, some frequencies don't come in clear. In Juniata County, PA our low band frequencies come off all three towers and are fine. They come in clear. It's the UHF channels, med 9 that comes in weak and we can't get anything from our dispatch channel. There is 3 towers in our county. The Tuscaora (Main tower that 99% of all communication goes off of) Blacklog (The tower that was just built not far from our station. Our tones and the 1 fire company) and the Shade (Western part of the county) The sites are NOT simulcast YET(to be done soon) I just don't understand why we can't pick up the main tower!