In-wall speaker wire installed wrong - any way to salvage? - AVS Forum
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post #1 of 10 Old 08-26-2012, 04:42 PM - Thread Starter
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I'm trying to figure out if there is any way I can salvage this and avoid a re-wire with an existing in-wall speaker wire setup. (The wire is already installed and the space is finished, painted, etc.) Hopefully I can make this understandable:

The installer was instructed to home-run speaker wire to 3 pairs of speakers for basic two channel audio. (e.g. run 2 conductor speaker cable from each speaker back to the head end)
The speakers are wall mounted 8 Ohm speakers. The installation calls for an impedence matching speaker switch to connect te three speaker pairs to a 2 channel amp. Pretty basic stuff.
The amp is rated at 150W into 8 ohms. The speakers are wall mounted on opposing walls. The room is more or less a long rectangle configuration with L/R speakers on opposite sides firing down / in / across the room.

What was installed:
The installer ran a single 2 conductor cable from the head end to the first speaker on the left side and a single 2 conductor cable to the first speaker on the right side and cut it.
The installer then daisy-chained a new cable from that speaker to the next speaker and once again to the last speaker. The same was done on opposite wall.
I have a single L/R connection at my head end, and two cut ends at each speaker location.

I could wire the speakers in parallel which if I am calculating correctly present a 2.67 ohm load to the amp. I could wire each side in series and present a 24 ohm load to the amp.
Neither option is very appealing. I think I understand series-parallel wiring but I don't know if I can even do this with the speaker wire that is in the walls... and with three speaker pairs...

I set up a test with the speakers wired in parallel just to confirm and while it works, my amp cuts off (standard thermal / protection circuitry) as I increase volume. The quality is OK at low to medium volume. I was told that the volume level in the test setup was not be sufficient. I am not comfortable driving the amp even at low volumes levels into a 2.67 Ohm load anyway.

So my question is what options if any do I have? I know that I can have new wires pulled per original design, but this means some damage to the now finished space and then repairs, etc.
I'm curious to know if there are any options I am missing? I have seen some (expensive) amplifiers that are supposed to be stable down to 2 Ohms. Would thatt be the only solution?
Is there a any sort of impedance "step-up" device that can be wired into the head end to present an 8 Ohm load?

The other issue is that the installer used cheap 16 AWG speaker wire. The individual runs are (approximatley) 25' - 30'. I've probably got a problem with that issue all by itself...

Final note is that while audio quality is always a concern, this is hardly a critical listening environment - it will be a typically busy / somewhat noisy environment. I would happily trade off some frequency response for a stable output from the amplifier.

This is a mess I know. I have a headache now. Thanks in advance for any advice.
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post #2 of 10 Old 08-26-2012, 05:15 PM
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What if you disconnect one of the speakers and just live with 2? Then you can parallel them and a reasonable amp should still be able to drive them. It would be worth a try at least smile.gif.

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post #3 of 10 Old 08-26-2012, 05:35 PM
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So instead of doing a little cheap drywall and paint, you're considering an "expensive" 2ohm-stable amp?

The HT bug has bitten you hard!
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post #4 of 10 Old 08-26-2012, 05:42 PM
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Quote:
Originally Posted by Propup View Post

The installer was instructed to home-run speaker wire to 3 pairs of speakers for basic two channel audio.
He did, believe it or not.
Quote:
...(e.g. run 2 conductor speaker cable from each speaker back to the head end)
Did you tell him this, or just assume he would do it this way based on your previous sentence?
Quote:
...what options...do I have?
Well, you can install a constant voltage system, which is what you are wired for. Or you could wire in series or parallel and use a transformer to get the impedance you want.
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post #5 of 10 Old 08-27-2012, 10:05 AM
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Are the existing cables fastened inside the wall? If not you can use the existing cables to pull new, correct cables.

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post #6 of 10 Old 08-27-2012, 03:54 PM - Thread Starter
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Thanks for all the input. I've at least got some options to offer. We might just go with a re-wire at this point.
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post #7 of 10 Old 08-28-2012, 03:01 AM
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What's the application for the system? Home or commercial? Background music or foreground? Sound for picture? PA? There are different optimal solutions for each application, and some would not require a re-wire.
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post #8 of 10 Old 08-29-2012, 10:27 AM
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Is the installer not going to correct his mistake assuming you were clear in the first place?

FWIW, an installer who would wire up a room like that is no one I would ever trust for future work. Even someone with a rudimentary understanding of electronics should have known better.

Not to step on the last poster's feet, but ALL options require a rewire. The work wasn't performed to the customer's specs.
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post #9 of 10 Old 08-29-2012, 12:47 PM
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Quote:
Originally Posted by Easyaspie View Post

...ALL options require a rewire.
No, it is just fine for a constant voltage system.
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post #10 of 10 Old 08-29-2012, 05:06 PM
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Quote:
Originally Posted by Colm View Post

No, it is just fine for a constant voltage system.
+1

Would also work as a low impedance system under certain criteria...that's why I asked how it's used, need more info before deciding on which way to go. Several options exist without rewire.
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