cryptic speaker selector instructions / impedance - AVS Forum
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post #1 of 8 Old 04-18-2012, 05:59 PM - Thread Starter
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Hello,
I am trying to drive 5 pairs of in-wall speakers from an Onkyo receiver using a 6-pair speaker selector (this one, if it matters: http://www.nextag.com/Pyle-PSPVC6-6-...60/prices-html)

The speaker selector manual says: "If you connect more than one pair of speakers, see 'impedance chart' on p. 6 to select the best terminals to connect. For best performance, make the connections based on how frequently you use each set of speakers." The chart on p. 6 shows impedance decreasing the more speakers are connected, which makes sense to me. What doesn't make sense is, the chart actually lists all the possible combinations of "on" speakers, A+B, A+C, A+D, B+C, etc. ... but still, for any given number of connected speakers, all possible combinations map to the same impedance.

So what is the manual trying to tell me? Does it matter what order I connect the speakers in, or doesn't it? I was going to connect them in descending order of frequency of use (from A always on, downward), just for intuition in using the buttons, but does it matter at all?

thanks in advance!
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post #2 of 8 Old 04-18-2012, 06:39 PM
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The chart is simple! Based on using 8-ohm speakers, the load on the amplifiers increases due to reduced impedance ...

# Speaker Pairs Used Load on Amp (ohms)
1 8
2 4
3 3.1
4 2.4
6 1.7

When the net impedance falls below 4-ohms, your amplifier will be very stressed! It matters little what combination you use, only the total number of speakers switched on.

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post #3 of 8 Old 04-18-2012, 06:57 PM - Thread Starter
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great, thanks, fair enough, 2 follow ups:
1. What's the benefit of the "protective circuitry" that my speaker selector claimed to offer, if I still have to worry about stressing the receiver? The speaker selector says it can play up to 6 pairs at once, is that just false advertising? [again, normal in-wall speakers, nothing fancy]

2. if I got a stand-alone amplifier, and put it between the receiver and the selector, would that help?

I kind of want to be able to play at least 4 pairs at once.
Thanks!
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post #4 of 8 Old 04-18-2012, 09:12 PM
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You are far better off to use a "70-volt distribution system" which can limit the amount of power being delivered to each speaker and .not. overload your amplifier. This is the method used to drive public address speakers. It involves placing a larger transformer at the amplifier and wiring smaller transformers at each speaker. Try Googling that. Post again here if you need help.

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post #5 of 8 Old 04-18-2012, 09:40 PM
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70 volt systems don't sound nearly a good as a 8ohm system.

The op needs to get an impedence matching speaker selector, one that gives a constant ohm reading to the receiver. Usually around 5-6 ohms.
Then they could have all 5 pairs running at the same time.


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post #6 of 8 Old 04-18-2012, 09:45 PM
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Do you need the volume controls on the unit? Or do you have volume controls in each room?

If you have volume controls in each room, which make and model?


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post #7 of 8 Old 04-19-2012, 07:13 PM - Thread Starter
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I don't have volume controls in each room, so I do need them on the unit. I saw "protective circuitry" in the description and I think I assumed that meant "impedance matching." Oops.
This one claims to have "selectable impedance magnification," would that have been what I needed? http://www.nilesaudio.com/product.ph...rdcdID=FG01044
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post #8 of 8 Old 04-21-2012, 08:20 AM
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See HERE.

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