Speaker Wiring: Need a HTF Electronics Wizard

Discussion in 'Archived Threads 2001-2004' started by Adil M, Jun 19, 2002.

  1. Adil M

    Adil M Supporting Actor

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    Here's the dilemma: I'm simply placing a receiver and cd player into an area designed to power in-ceiling speaker pairs in 7 rooms of the house. It was supposedly prewired 14 years ago, but only the left speaker works. Since none of my pictures from my garbage digital camera came out, I'm going to have to wing the description.

    Key:
    A.(.) = means nothing it is only there so the diagram looks right
    B.() is a place where speaker wire can be attached

    1. There are two gold boxes attached to the wiring in the wall. The boxes are labeled right and left and each box has it's own (+) and (-). These I plugged into the receiver to only get the left speaker in each room to work.

    2.
    ......._____Right.Box_____
    .......|............................|
    .5.0.62
    .......|.....Watts..............|
    101.25
    .......|............................|
    .C.2.5
    .......|............................|
    ........___________________



    It's got a black wire which connects C from the Left to the Right Box. Also, 10 and C are connected in the Left to the bundle of wiring (looks like a biwire w/ 4 wires) which disappears into the wall. The Left is only connected on the 10 and there is a spare wire which looks like it should be connected to the C, but that didn't work.

    ......._____Left.Box______
    .......|...........................|
    .5.0.62
    .......|.....Watts............|
    101.25
    .......|...........................|
    .C.2.5
    .......|..........................|
    .......___________________



    3.
    Here's the other sides of the boxes. Work w/ me here.

    ....._____Right.Box_____
    .....|...............................|>C
    .....|.....Labeled.............|
    .....|......Sec...................|>4
    .....|......Ohms................|
    .....|..............................|>8
    .....|..............................|
    .....|________________|>16

    ....._____Left.Box______
    .....|...............................|>C
    .....|.....Labeled.............|
    .....|......Sec..................|>4
    .....|......Ohms....... .......|
    .....|.............................|>8
    .....|.............................|
    .....|________________|>16

    The C and the 8 are connected to what looks like should be the (+) and the (-) of a speaker wire. Since there's a Right and Left Box there is a Right and Left speaker pair. Unfortuantley only the Left speaker works and if I hook up the Left Speaker I get whole bunch of feedback and the music I'm playing appears to be very lightly coming from the receiver itself. Any help here? Is it hooked up right? How should I hook it up? Etc.? Thanks A lot to anyone who can figure this out.
     
  2. Phil A

    Phil A Producer

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    If you know a cable (or telephone) installer, get a hold of a 'Fox and Hound.' It is a tool used to find buried wiring that basically emits test tones to let you know when you have found the wire. Here is one site I found with such tools: http://store.yahoo.com/tmt/foxandhounwi.html
     
  3. Wayne A. Pflughaupt

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  4. Adil M

    Adil M Supporting Actor

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    These gold boxes are called "Realistic Cat No. 32-1031." They are placed between the speaker outs of the receiver and the wall where the wire disappears and eventually comes out to the rest of the speakers.
    It appears to be some sort of (guess) Impedance adjuster.
    In part 3 above the side labeled Ohms has a speaker wire connected to the C and 8 terminals. This speaker wire is then attached to the receiver.

    The signal appears to travel like this.
    1.Receiver connected to Gold Boxes through the C and 8 terminals on each box. Then from the other side they attach to the C and 10 connections like in part 2. However, there is a speaker wire, in addition, which connects the C from one box to the C from another box. These 4 individual speaker wires travel into a bundle in the wall to 7 speaker pairs throughout house and patio.

    I have an ok picture, that I could email.
    I know the diagram isn't the best, but it's a real pain to make one of those look right.
     
  5. SteveChrist

    SteveChrist Extra

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    This is what I found from the Rat Shack...
    Link
    Hope this helps...
    S.
    Here's a pic.
    [​IMG]
     
  6. Blake R

    Blake R Stunt Coordinator

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    I believe Wayne may have nailed it as a 70v commercial distribution set up. The transformers can be tapped according the wattage of the speaker on the tap. The transformer steps down the voltage and also acts as an impedance transformer.

    Maybe.
     
  7. Wayne A. Pflughaupt

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    Every now and then the experiences of my former life as an pro-audio installer comes in handy!

    Yup, Adil, those are transformers for a 70V system. They are typically used commercially when they want to safely drive a lot of speakers from a single amp. Anytime you go to a restaurant or office and see those round ceiling speakers everywhere – that’s what I’m talking about. Usually those speakers have one of those transformers attached directly to them.

    Since you said this house has speakers in seven rooms, this would be a good application for a 70V system, if mid-to-low-fidelity performance at background levels was the objective.

    The system requires an amplifier with 70V output, or at least an converter to connect to a regular amplifier. Radio Shack has one available – #320-1032.

    But I think it would be better to get a used commercial 70-V amp on e-bay; they’re pretty cheap (they’re usually mono, so you would need two). You could feed it a signal from your main system. So the remote speakers would be totally isolated from your home theater system.

    Here’s how the system works:

    The amplifier has a steady 70V signal present on its speaker terminals. You use regular speaker wire to the various locations; 16-guage is fine for this application. At the remote speaker location, the speaker wire from the amp connects to “watts” side of the transformer. Speaker (-) goes to the “C” (common) terminal; speaker (+) goes to one of the numbered terminals - .62, 1.25, 2.5, 5, or 10, depending on how many watts you want to give that particular speaker. (Ever go into the bathroom at a restaurant and the background music is blaring? The speaker in there needs to be tapped at a lower wattage from what’s being used in the larger, open areas. Idiot installer.)

    The other side of the transformer is connected to the speaker itself, again speaker (-) to “C,” and (+) to 4, 8, or 16 ohms, depending on the know impedance of the speaker.

    Once you determine how many watts you would be using at each location, you can figure out how powerful your amp needs to be. For instance, in a home situation you would probably want to tap at the maximum wattage at each location. So that’s a minimum 70 watts-per-channel amp that is needed. Reserve power never hurts; for this system, “reserve power” doesn’t mean more headroom – it only means the amp will not have to work as hard.

    The first thing I would do, Adil, is disconnect the transformers from all the wires so you can test the remote speakers (keep the volume low). If you now have the transformers connected between your amp and the speakers, that would explain why they aren’t working right.

    If the explanation above doesn’t make sense I can send you a picture diagram.

    Regards,
    Wayne A. Pflughaupt
     
  8. Adil M

    Adil M Supporting Actor

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    That picture is exactly it. It's about 12 yrs old and that picture is far superior to the one I took w/ my digital camera. Alright, Wayne, first I disconnect the transformers and test the speakers at low volumes to make sure they work.
    (Then I unsolder all the 12 yr old wiring and replace it w/ new wiring, b/c all the copper is dark brown) BTW, how do I rewire the transformers. I understand the side where I just pick the ohms of the speakers, but what about the other side. The way it is wired now the two C's are connected on the side w/ the wattage??
    Another ?, right now I'm using a bookshelf receiver to power it, b/c my parents had bought an Optimus receiver (w/o my permission) and it blew, I believe. We have a spare dvd player, so I was thinking of adding a 2 channel amp. I can get the Onkyo m282 100 watt x 2 amp for under 200 dollars new or a HK amp for like 250 new. I've got a feeling though I'd do better if I just got a real nice used 2 channel amp. Since, you deemed this system low-mid fi, is it worth worrying too much about which amp to use? My parents intend to use this system a lot more for house parties. Thanks a lot guys. [​IMG]
    Any other tips on checking this system out considering it's 12 yrs old. BTW, all the wiring is solid. I can't believe you guys were able to make something out of that diagram. :b
     
  9. Wayne A. Pflughaupt

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    Adil,

    Happy I could be of some help with this. Understandably, most people into home audio have no idea what this kind of system is all about, since they aren’t usually used for residential applications. For instance, in three + years on this Forum, this is the first time I’ve seen anyone inquiring about a 70V system.

     

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