Paging Systems

[markp1928]

we have a customer with 200,000 sq ft warehouse and wants a new paging system. it is my understanding that with only PLT licensing, i can't install a 70 volt amplified system. would a 25 volt system potentially get the job done. this warehouse is 600 feet long and has a lot of ambient noise.

 

[zbang]

Will a 25v system work? Maybe... depends on how much wattage you want to pump out. One option is use satellite amps to shorten the speaker wiring (but that adds points of failure), another is to up the speaker wire gauge. If nothing else, you can contract someone else to install the wire and you sell the "system".

 

[hbiss]

it is my understanding that with only PLT licensing, i can't install a 70 volt amplified system.

I would check on that. If you understood what a "70 volt" system is it's all CL2 now, the same as a 25 volt system.

Another option would be from Valcom that uses 24VDC and an audio pair to speakers that have small amps built in- you can run telephone CAT3 around to everything. Give them the layout and Valcom will design it for you.

-Hal

 

[bccarlso]

zbang - "One option is use satellite amps" - have a list of mfg's you've used satellite amps before? My paging systems haven't required those (yet), but would be nice to have in my back pocket should the need arise. Thanks.

 

[zbang]

Any amp can be used as a satellite amp, although I'd use one that needs a screwdriver to adjust the level (or put it in a locked box). Not sure about Valcom, but i think Viking and Bogan make self-amplified speakers.

 

[hbiss]

Valcom, but i think Viking and Bogan make self-amplified speakers.

That's what I said though maybe in not those words.

One option is use satellite amps" - have a list of mfg's you've used satellite amps before? My paging systems haven't required those (yet), but would be nice to have in my back pocket should the need arise. Thanks.

No such thing as a "satellite amp". You almost never need to use anything but one amp to feed a system. I can ask the guy whose company did JFK airport in NYC if he daisy chained amps. Don't think so. Knowing him, if there were multiple amps there was line level balanced audio run throughout the facility to feed any additional amps wherever they were.

On the other hand, I know some malls where the individual stores or departments in a large store had their own amp and system. The amp input tapped off the mall system 70.7V wiring for music and announcements but allowed them to make their own pages for their store.

-Hal

 

[zbang]

to feed any additional amps

Those are the satellite amps (amps remote from the main stack, usually fed at line level from the controller/source). It all depends on the load and power settings.

 

[hbiss]

Those are the satellite amps (amps remote from the main stack, usually fed at line level from the controller/source). It all depends on the load and power settings.

Right. That's what I was saying about JFK. That wouldn't really be satellite amps, but actually a bunch of separate systems fed from a common line level source. They would be just regular PA amps of your choosing, nothing special.

-Hal

 

[bccarlso]

That's what I said though maybe in not those words.



No such thing as a "satellite amp". You almost never need to use anything but one amp to feed a system. I can ask the guy whose company did JFK airport in NYC if he daisy chained amps. Don't think so. Knowing him, if there were multiple amps there was line level balanced audio run throughout the facility to feed any additional amps wherever they were.

On the other hand, I know some malls where the individual stores or departments in a large store had their own amp and system. The amp input tapped off the mall system 70.7V wiring for music and announcements but allowed them to make their own pages for their store.

-Hal

Hal, correct, though depending on the number of zones the owner wants, there might be need for an amp with more channels, or multiple amps. Typically via a network zone encoder line or aux input to the amp. Or if you want to spend lots of money, no amplifiers, but built-in PoE powered "VOIP" style speakers. They're very pricey, though I've used them at the request of owners before.

 

[bccarlso]

Those are the satellite amps (amps remote from the main stack, usually fed at line level from the controller/source). It all depends on the load and power settings.

Ah, by satellite you just mean additional remote amps… which I described above. I thought you literally meant satellite-fed amplifiers! Silly me.

 

[hbiss]

Hal, correct, though depending on the number of zones the owner wants, there might be need for an amp with more channels, or multiple amps.

Typically multiple zones would have the amp(s) located together in one place if for no other reason than ease of servicing and troubleshooting. A system can be designed any way the designer wants, but like anything else there are standard practices and topologies that should be followed if you don't want your work to look like somebodies brother-in-law bought a bunch of stuff off the internet.

-Hal

 

[bccarlso]

Typically multiple zones would have the amp(s) located together in one place if for no other reason than ease of servicing and troubleshooting. A system can be designed any way the designer wants, but like anything else there are standard practices and topologies that should be followed if you don't want your work to look like somebodies brother-in-law bought a bunch of stuff off the internet.

-Hal

Yes, typically. Although, to save on wire, sometimes they may be remote and network-connected. Especially if one zone physically separated from another zone means you save on wiring and labor by building it out with that topology. I rarely get into the means and methods as I'm just the design engineer, but it's interesting to think about from a T&M standpoint. Contractor will do whatever is cheapest that they can get away with, inevitably! At least in the low bid world I work with…

 

[tom baker]

Your question about PTL licensing is specific to your jurisdiction. NEC does not cover licensing, permits, etc.