Bought a Pioneer Elite SC-87 with 3 zones but I need more zones. So as to not hurt the amp can I just wire Impedance Matching volume controls at the three extra zones I want to add and wire them to one of the original three zones? Thanks
If you can clarify, You have a total of 6 'spaces' that you want to run using the SC-87, which can handle 3 zones. Therefore, you want to run 2 'spaces' off of each receiver zone? IF that is the case, the answer to your question is "yes and no". Take a quick look at this short website that has diagrams showing you how you would do this: How To - Car Stereo - Series vs. Parallel Wiring So, yes, it is possible, but it depends on what the impedance of the speakers you have AND what impedance loads are supported by that receiver. Do realize, that driving multiple speakers off of a single zone will reduce the dB level at each speaker for all power levels (power output by the receiver is dependent on impedance AND is getting split between two speakers).
Here's one way to go about it: Speaker Selector Switches in the Home Audio / Video Department at Parts Express | 126
Thanks Guys I was under the impression that the more speakers you add, you cut down the resistance the amplifier sees(one speaker = 8ohms, two = 4ohms, etc). This means if you add a lot of speakers its like shorting the + and - speaker leads and over loading the amp. The Impedance matching volume control or speaker selector adds a load to the circuit to stay at 8 ohms. So either solution works and is safe for the amp? Thanks Bill
Whether resistance goes up or down with multiple speakers depends entirely upon how you wire them. If you wire them in series, then the resistance the amp sees will increase. If you wire 3 speakers in series, for example, the total resistance will be R1+R2+R3. If you wire them in parallel, however, the resistance will decrease. The formula for resistance in parallel wiring is more complicated. In general, if you are talking about 2 identical speakers, then the resistance of the pair will be double if you wire them in series and will be half if you wire them in parallel. It is possible to combine wiring types, for example to drive 4 speakers from a single amp by creating two pairs of serially wired speakers and then wiring those 2 pairs in parallel. If you do this with 4 ohm speakers, then the load from 4 speakers would still be 4 ohms because you double the resistance of the serial pairs by putting them in series, and you half the resistance by wiring those pairs in parallel. The combo of series and parallel wiring is very frequently used for home theater seat shakers, where you often need to drive large number of shakers with a single subwoofer amp. You can usually find a wiring approach that will make the amp happy with multiple speakers. If you can't get the resistance exactly what you want, it is safest for the amp to err on the side of too much resistance rather than not enough. There is an online calculator here -> Speakers in Parallel Calculator - Geoff the Grey Geek
