Wiring Loudspeakers in Parallel

Q: I currently have a set of WDST (Klipsch Synergy Premiere S6) on the surround channel of my RX-V2095. I'd like to add a set of floorstanding speakers (Klipsch Legend 10) to the same channel, and wire it IN PARALLEL. Other channels: mains, KLF-30 (bi-wired); center, KLF-C7; no sub as yet (30's shake the ground plenty hard) A friend is doing this very thing with no ill effect, but with a Sony STR-DE925; I haven't heard back yet, which impedance his receiver is set to. He also reports that wiring in series sounds just dog-awful. Now, I have heard all sorts of various things about the Yammie receivers - for example: Using the 4ohm setting cripples the output of the receiver and just sounds plain bad in general.

A: While it is usually not recommended to wire 2 sets of speakers in parallel to a receiver because of the low impedance it represents, I believe in your case, it will be fine, for the following reasons: Uyuutyn

1. The Yamaha RX-V2095 has a very ample power supply that is capable of driving a 4 ohm load continuously assuming good ventilation is provided. You should have at least 4" of space above the Receiver and an open front or back panel where the Receiver is installed to allow heat to dissipate. In addition, the Power Supply is much more robust and stable on the Yamaha RX-V2095 than on the Sony STR-DE925, so if your friend is successfully doing this with his Receiver, it will be a breeze with yours J.
2. Klipsch Speakers are generally very efficient and loud speakers (8 ohm, SPL > 90dB) that require very little power for loud listening levels. They should present a moderately easy load even with two of them wired in parallel ( 4 ohm load) to each of the rear channels of the Yamaha Receiver.
3. In most cases, surround speakers are closer to the listener than the mains and thus are attenuated 2-3 dB to compensate, thus the amplifier does not have to work as hard to output same volume level as the mains.

Other Options
If you find that you cannot achieve enough output volume on the rear channels with the amps in the RX-V2095, buy a separate 2 or 4 channel channel power amp and connect the inputs of the power amp to the rear preamp outputs of the RX-V2095. If you are using a 4-channel power amp, you will need to connect a y-cable for each channel going from the RX-V2095 into the power amp. This will feed the signal of the RX-V2095 to all 4 channels of the power amp. You may than wire all the rear speakers to the power amp.

Do NOT do the following:

1. Connect the 2 rear speakers for each channel in series. Doing so may cause phasing problems as well as attenuating the output level by at least 3dB since the amplifier output voltage supplied to each speaker will be halved due to the overall series system impedance of 16 ohms presented to the amplifier.
2. Select the 4 ohm setting on the backpanel of the RX-V2095. Doing so will significantly limit the rail voltage feed to the power amps and thus reduce dynamics, bass output and damping factor. This switch was put on the Receiver for marketing purposes, and so that it can meet UL approval for heat dissipation when presented a 4 ohm load continuously. With proper ventilation, this should not be a problem.

Note: Always remember, in most cases, if you are driving the Receiver too hard, it will shut off long before damage can occur the output devices. Using caution and common sense will most likely help you avoid this scenario, and/or at least prevent multiple occurrences.