Speaker Wiring (Commercial Space)

[aka Larry]

My boss has entered into a joint venture with two others to start a fitness center. Discarding the fact I think it's a terrible idea, let's move on.

They need to place two floor speakers on opposite ends of the space, and opposite wall from the receiver. The space is a section within a building with fire walls sectioning off the other businesses. My plan was to add low voltage old-work style boxes on the opposing walls and run the speaker wires across the drop ceiling. Normally this would be easy peasy, but since the sheetrock walls are fire walls, the sheetrock goes from floor to roof instead of just stopping just above the drop ceiling.

Right now I have no idea if the walls are insulated and/or have cripple studs to impede my plan of just fishing the wiring through the walls. Obviously I need an entry and exit hole for the wires so I can use a fish tape, but I don't know if I can legally cut an opening above the drop ceiling for the entry hole since it's a fire wall.

As last resort would be to use surface mount wiring, but it just looks tacky IMO.

What do you guys think?

 

[where2]

I think "plemum rated wire" with orange spray foam fire block around the wires "may" work, but we'll see what someone who installs wire for a living thinks.

Personally, for a large space like you are talking about, you really should look at 70V amplifiers and multi-tapped commercial speakers. The voltage drop running extra-long amplified wire runs is going to mess with your speaker impedance.

 

[ishiboo]

Plenum wire is only required if the drop ceiling is used for air supply or return. If there are independent ducts for both these things, it is not required... which is important as it's pricey

You can drill/cut a hole, I would caulk it with rated (red) fire caulking if you can get by with just a hole and have it fall down to the box.

If not, cut a hole and repair with normal drywall practices (joint compound and tape)... it is fine to use a wood backer to hold it in.

 

[Thumper68]

I do this for a living.

The first thing to do is check and see if it needs to be done by a licensed power limited contractor. (here in MN that would be the case.)

If you can do it your self then your plan would be fine. Don't just lay the cables on top of the ceiling it must be supported a minimum of 4 inches above to allow for removing tiles. I would recommend running the cables around the perimeter fasting them every 4 feet with cable ties with eyelets.

To fish the cable down the walls cut a hole just big enough to fit a plumb bob, if there is insulation you can bounce the bob and it will work its way through, once the bob is at the hole pull it out and tape the cable to it, pull it down and then retrieve the bob. To seal the hole I use Hilti FS-1. The caulk needs to completely fill the hole to a depth of 5/8 inch.

You cannot repair the hole with regular drywall compound, in a fire it will shrink and fall out allowing fire into the wall and the next space.

 

[mike_81]

while you may not need plenum rated wire (if the space above the ceiling tiles is for return air you need plenum wire, as mentioned), otherwise, if it hidden behind a wall at any point (sounds like it will be) you need in-wall rated wire, called FT4.

monoprice dot com sells all kinds of speaker wire for really cheap. i installed it in my setup in my basement and it has worked flawlessly.

 

[kbs2244]

ducksface has the idea.
Simple and in the end cheaper.

 

[hifi_hokie]

Except if something fails, you're left with something that can't be easily fixed, short of buying an entirely new setup.

Never been a fan of wireless speakers, even for applications like this where sound quality isn't the primary goal.

IMO, get a few JBL Control 26s and a 70V mixer/amplifier (Crown would be my preference if buying new, but you can find used TOAs or Bogens on Ebay all day long), knock a few holes in the tiles and have at it. Floor speakers in a fitness center sound like an invitation for something to happen with them, especially if someone gets a little enthusiastic with a barbell

 

[jeffmoss26]

What the other guys have said.
70 volt systems are the way to go for a commercial application.
Just make sure someone does not install an 8 ohm speaker later on!

 

[Isissound]

In Cieling is by far the way to go just make sure local code doensent require a fire back box although for most drop cieling applications i reccomend a speaker with a built in back box or adding one. it just gives the speaker a nicer sound

 

[bseant]

is anything going to have to be inspected?