Ambiance speakers

[fs483]

Hello,

I have a customer who whishes to have speakers installed in their place of business. The place is a spa/message shop and the owner would like to be able to broadcast music to each room. I'm thinking of just using regular speakers that attach to the ceiling tiles like the ones in small boutiques. I tried searching the online catalog for ADI but couldn't find them, can anyone point me to the proper page ? Also, the owner plans on broadcasting only from one source to every room. They have about 10 very small rooms and the volume will be very low. In this case, do I hook all the speakers in parallel or do should I home run all the speakers ? If I hook all the speakers in parallel than I can easily hook the wires to a small wallplate with jacks so the customer can just plug in the stereo. Plugging all the speakers in parallel will surely affect the impedance right ? However if I home run all the speakers, I'm going to have a lot of wires back at the source (10 speakers * 2 wires per speaker = 20). I don't want to put wallplates with 20 jacks. Do these speakers need power (through a transformer) or do I just hook them up to the speaker output of a stereo ? What kind of wire should I use (gauge) and if the speakers do need power should I use a 2 pair wire all bundled together or just basically run 2 separate pairs of wire and avoid any electrical interferance (like humming).

Thanks
bootleg

 

[AvayaNovice]

Hi bootleg,

You have the option of using powered speakers, or passive speakers that require an amplifier.

In my experience, powered speakers usually require two pairs of wire, whereas passive speakers require one pair.

You can use standard Category 3 cable for the speakers. And I would simply loop them. I'm not sure if impedence is an issue, I recall running 6 speakers in parallel and not having a problem.

If you use powered speakers, all you need is an interface to convert from stereo line level output to whatever your speakers require. Passive speakers have a special amplifier, and it usually has a line in source so no conversion is needed. Powered speakers may require a conversion.

The reason powered take two pair is one pair for signal, one pair for power. That being said, the only limit on the number of speakers in the chain is the capacity of the power source for the speakers.

Hope that helps.

As far as ADI catalog, sorry... we don't use them. Sprint North Supply carries a variety of products that will do the job though.

 

[fs483]

HI AvayaNovice,

Yeah that's what I though too. I'm going to shop around my local suppliers to see what they have to offer.

Thanks
bootleg

 

[TouchToneTommy]

I would recommend using an amplifier with a "70-volt" output, instead of 8-ohm. Then use ceiling speakers with 70-volt matching transformers. Run single-pair sheilded wire, looped is fine, tap the speakers at 1/2 or 1 watt each. Many models of ceiling speakers include an attenuator built into the center of the speaker grille. Different "grades" of speakers are available, some with better frequency responce and tweeters/midrange cones.

Check paging-solutions.com, perhaps also valcom.com or

http://www.bogen.com/telcopro.htm

 

[AvayaNovice]

Tommy,

The ones that EOC required were active and self powered, which is why Cat-3 was acceptable, yeah?

 

[daronwilson]

Indeed a 70 volt system will likely function much better. You don't need such large speaker wire to handle the loss, and you can tap each speaker for 1/4, 1/2, 1, 2, 3 watts or so depending on the model. This allows you to tailor each speaker for the area and change as needed. If you want the customer to be able to adjust the volume, there are ceiling speakers with screwdriver adjustments in the middle, or some that have a knob that is easy to adjust.

I would suggest at least 20 gage speaker wire, shielded if you prefer and if you are going to be close to sources of interference, though 70 volt systems are very forgiving. Keep the shield in tact wherever you cut in a speaker, and loop the speakers. If there are logical 'zones' in the building, you might make a run for each zone, it just makes troubleshooting easier later if you have a problem.

Select an amplifier that will deliver the needed power and leave you some headroom. Let's say you have 20 speakers, and you are going to tap them at 1/2 watt, you will be drawing 10 watts total, so I would get a 25 watt amplifer or so. That way you have the volume set at 1/2 or so on the amp, much less risk of peaks and distortion causing your a problem.

Good Luck

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[fs483]

Ok, let's see if I understand :

1- connect the audio source to the "70-volt" amplifier
2- connect the power to the "70-volt" amplifier
3- run a single pair shielded wire from the amplifier to a 70-volt matching transformer
4- connect the output of the matching transformer to the 8-ohm input on the speaker
5- connect the rest of the speakers in parallel to the "70-volt" amplifier ?

Sounds easy, i'll have to check the costs.

Thanks TouchToneTommy.

 

[AvayaNovice]

When I said category 3 wiring, that was in reference to powered speakers, not passive speakers -- my apologies for not being clear about that.

Passive speakers indeed use shielded wire, and it is heavier gauge.

 

[AvayaNovice]

bootleg, the transformer and speaker are one unit, if I'm not mistaken. Each speaker has a 70 volt transformer on it.

 

[daronwilson]

Yup, the 70 volt transformer is mounted on the back of the speaker and has multiple inputs or 'taps' that you choose from on the primary side. So you loop your 70 volt line to all the transformers and select the level you want at each one. One of the wires is common (often black) then there is a different color wire for each power you want. Lots of sound, choose the 3 watt wire; little sound, chose the 1/4 watt wire.

TOA is an excellent choice for an amplifier, though it may be on the high end of what you want. There are many other brands out there to choose from. Most commercial amplifiers will do 8 ohms or 70 volt, some have 4 ohm and/or 25 volt as well.

This is a very common installation, I've done entire malls and large stores this way. Good quality speakers and don't over drive them, and you will do very well.

We routinely use 20 gage wire for most installations, if you are hauling it a long way you might size up to 18 or so. Sounds like your installation is small enough that 20 or 22 gage should be fine.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com