Wiring additional speakers to whole house controllers - AVS Forum
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post #1 of 13 Old 01-06-2011, 02:16 PM - Thread Starter
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Looked at some of the other post and didn't find anything that matched my query, was hoping some kind soul more versed in electricity and speakers might help me.

Have a new house that was wired with Cat6 wiring going to 4 zones (gang boxes) from a central location. Then from each of those gang boxes where one end of the Cat6 terminates, I have speaker wire also terminating that goes to various in-ceiling speakers.

My original vision was to buy a Whole House Audio system that has controllers that use the CAT6 for power and control and also send the signal to the speakers that are in the ceiling (as opposed to one of those systems where the speaker runs terminate all the way down where the CAT6 or other control wires terminate)

Anyway the problem lies in that now that I'm actually at the point of buying equipment like in-wall controllers, I haven't found a controller that can handle 4 speakers (2 pairs), every manual I've read from a plethara of manufactures either says stuff like "Use TB2 to connect one pair (only) of 8 ohm audio speakers to the volume control." or says nothing at all.

So the question is, if I splice essentially 8 speaker wires (+ and - for 4 speakers) (see my crude drawing below) in to 4 speaker wires and then plug those wires in to the controller, am I'm risking frying the controller or burning my house down, or am I just going to lose 50% of the power to speakers?

This is for background music, they're 60watt speakers so really 30 watts of juice to them is fine for my purposes. I just want to be sure I'm not doing something totally verboden in the electrical or audio world.

Thanks

Charles

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post #2 of 13 Old 01-06-2011, 06:46 PM
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Keep in mind the speakers handle up to 60w of power, but the system power depends on the amplification. The Lyriq system pictured is a variation of ABUS. ABUS is usually around 6 watts per channel. A system like the Onq is 20wpc. So you have 20wpc halved with 2 pairs of speaker: 10wpc. Now you run into the issue of impedance matching. 2 pair of 8 ohm speakers = 4 ohm load on the amplifier. The onq should not have a 4 ohm load. So you could take the output of the onq into a local passive volume control with x2 impedance matching and out to 2 pair of speakers. There will be some insertion loss, and you only had 20wpc divided by two, but it would be suitable for background music.
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post #3 of 13 Old 01-06-2011, 07:02 PM
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Quote:
Originally Posted by vtcrusade View Post

Anyway the problem lies in that now that I'm actually at the point of buying equipment like in-wall controllers, I haven't found a controller that can handle 4 speakers (2 pairs), every manual I've read from a plethara of manufactures either says stuff like "Use TB2 to connect one pair (only) of 8 ohm audio speakers to the volume control." or says nothing at all.

I'm confused - are you trying to do this with one zone controller instead of 4? The lyriQ and other A-Bus systems like it have the amp built into the control pad which then powers the speakers in that zone. So for 4 rooms, you have four keypads, each controlling one pair of speakers, allowing for independent volume control and source selection.

And as iimig said, you should not hook up a 4-ohm load (two pairs in parallel) to these amps...

Jeff

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post #4 of 13 Old 01-07-2011, 06:46 AM - Thread Starter
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Jautor - I'm sorry to be clearer, I have 4 zones and 4 controllers, the problem is that in each of the 4 zones there's 4 speakers not 2, so it's not 8 total speakers in the house it's 16.

Could I in theory put in another controller for each zone, sure, but that will look dumb as hell on the wall, 2 controllers sitting next to each other, not to mention confusing to anyone but me using the system. Plus, I'd then have to put in an additional Cat6 run from the new controller to the termination point.

IImig - Okay, so we've got a possible solution brewing. So where would this "local passive volume control" fall in the system, between the amp and wall controller?
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post #5 of 13 Old 01-07-2011, 08:32 AM
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the local passive volume control has amp IN and speakers OUT. The amp IN is actually the ABUS keypad (it is the wall controller and amplifier.) The speakers OUT is all 4 speakers.
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post #6 of 13 Old 01-07-2011, 11:51 AM - Thread Starter
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So this would be another controller that would be installed next to the Zone controller in the wall? If not I'll have to think of something else, because the speaker wire terminates at the gang box where the controller goes, not all the way down where the Cat6 wire terminates in my wiring closet.
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post #7 of 13 Old 01-07-2011, 12:35 PM
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That is correct. They can even be ganged with each other.
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post #8 of 13 Old 01-07-2011, 02:52 PM
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Having two volume controls would annoy me. Another way to accomplish what you want is to use two pairs of 4-ohm speakers wired in series. You could also use 8-ohm speakers in series, but you would have to turn the volume control up.
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post #9 of 13 Old 01-10-2011, 09:50 AM - Thread Starter
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So basically I need to get one of these:

http://www.cambridgeaudio.com/summary.php?PID=81

I'd wire my 4 speakers in to it, as well as whatever zone controller I'm using?

I like the fact that this KP-10 apparently can use my current Cat6 run, as I won't have to do any additional cabling.
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post #10 of 13 Old 01-10-2011, 11:41 AM
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That IS a zone controller. What iimig was suggesting is to add an impedance matching volume control next to your zone controller like this:

http://www.parts-express.com/pe/psho...60&ctab=5#Tabs

The instructions has a chart which tells you what to set it to depending on how many pairs of speakers you are connecting.
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post #11 of 13 Old 01-11-2011, 06:49 AM - Thread Starter
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Excellent! Thank you for the advice on this guys!
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post #12 of 13 Old 01-12-2011, 11:20 AM - Thread Starter
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I'm still going to buy the impedance matching controller. But I did find this interesting tid-bit on Wikipedia. Perhaps modern whole house audio systems don't need such devices. Just wire as many speakers as you want directly to the amp.

Loudspeaker amplifiers

Many modern solid state audio amplifiers do not use matched impedances, because semiconductor based amplifiers do not have output transformers. The driver amplifier has a low output impedance, such as < 0.1 ohm, and the loudspeaker usually has an input impedance of 4, 8, or 16 ohms, which is many times larger than the former. This type of connection is impedance bridging, and it provides better damping of the loudspeaker cone to minimize distortion. The misconception arises from tube audio amplifiers, which required impedance matching for proper, reliable operation. Most of these had output transformer taps to approximately match the amplifier output to typical loudspeaker impedances.
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post #13 of 13 Old 01-14-2011, 09:05 PM
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All I know is that the few times I have put a load beyond the specified minimum impedance on an amplifier, it has resulted in the amplifier going into a protection mode.

What the article states may be true, but at the same time most protection circuitry probably doesn't allow a low impedance situation.
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