Bi-Amping with the RX-Z7

[cdub]

According to the manual in order to bi-amp my mains (M80's) with the RX-Z7 I have to use the rear surround speaker terminals on the Z7. Since I already have a 7.1 setup, I obviously don't want to loose the rear surrounds to do this. I can go with monoblocks for the M80's unless there is another solution I am not aware of. In that regard I have a few questions:

1 - Can the Zone 2/3 terminals be used somehow instead of the rear surrounds? I kind of doubt this but you never know.

2 - The Z7 manual states the min RMS output @ 8 ohms is 140 WPC, is there a way to calculate what the WPC output would be @ 4 ohms based on this? The manual only states the dynamic power breakdown @ 8/6/4/2 ohms.

3 - Based on Gene's advice, I will be leaving the Z7 set to 8 ohms minimum even with the 4 ohm mains and 6 ohm center. Does this effectively keep the WPC at the 8 ohm rating or is the WPC controlled by the actual impedance of the speaker?

4 - The M80's are rated for 400 Watts max input, would I be risking overpowering them when bi-amped since the Dynamic Power (IHF) of the Z7 is rated at 8/6/4/2 ohms = 170/205/265/345 WPC for the mains?

 

[MatthewB.]

Most people will tell you that Bi-amping does no good at all, it basically is just doubling the speaker wire and you will get maybe a 1% improvemnet in sound. Same can be done by just buying thicker gauge speaker wire. I feel your time (and money) will be better spent on room acoustics. I would go with not bi-amping.

I would set the selector switch to 6ohms (so you don't overpower the amp in 8ohm position - you are basically restricting the voltage when going with a lower ohm to help control, the power). In theory a quality should double the watts going from 8ohm to 4ohm (so 100watts in 8ohms would do 200 watts in 4ohms, but in recievers those numbers vary greatly, so I can't give you a set number, but the watts should be higher. And no you would not be overdriving the speakers, most of the time, your receiver is chugging along at 2-5 watts total, it's only during brief explosions or intense scenes that your reciever would push more power to drive the mid range and woofers. If you have a sub, than I wouldn't worry at all.

 

[jayhawk069]

I would set the selector switch to 6ohms (so you don't overpower the amp in 8ohm position . . .

See Gene D.'s emphatic comment in the RX-Z7 thread nearby.

 

[bandphan]

Impedence switches on most modern gear reduces power output and lowers the level at which clipping will occur. And unless the op moves up into the 250 wpc range of outboard power, id drive them as is.

 

[gene]

Most people will tell you that Bi-amping does no good at all, it basically is just doubling the speaker wire and you will get maybe a 1% improvemnet in sound. Same can be done by just buying thicker gauge speaker wire. I feel your time (and money) will be better spent on room acoustics. I would go with not bi-amping.

You're confusing biwiring with bi-amping.

I would set the selector switch to 6ohms (so you don't overpower the amp in 8ohm position - you are basically restricting the voltage when going with a lower ohm to help control, the power). In theory a quality should double the watts going from 8ohm to 4ohm (so 100watts in 8ohms would do 200 watts in 4ohms, but in recievers those numbers vary greatly, so I can't give you a set number, but the watts should be higher. And no you would not be overdriving the speakers, most of the time, your receiver is chugging along at 2-5 watts total, it's only during brief explosions or intense scenes that your reciever would push more power to drive the mid range and woofers. If you have a sub, than I wouldn't worry at all.

This is really bad advice. The impedance switch set to the "low" setting will drastically increase the chances of amplifier clipping. Clipped amps damage tweeters. You're better off with more than less power virtually ALL of the time. The switch is there for one purpose only - pass UL heat dissipation tests into 4 ohm loads by derating the available output power at 1% distortion under a 1kHz continuous test condition. The only time it should be set for "low" mode is when Yamaha submits the product to UL for certification purposes.

 

[gene]

4 - The M80's are rated for 400 Watts max input, would I be risking overpowering them when bi-amped since the Dynamic Power (IHF) of the Z7 is rated at 8/6/4/2 ohms = 170/205/265/345 WPC for the mains?

dynamic power doesn't destroy speakers. Continuous power does.

Please read:
http://www.audioholics.com/education/loudspeaker-basics/loudspeakers-power-ratings-part-iii-the-test-results

(note the woofer under test was an Axiom midrange)

 

[cdub]

dynamic power doesn't destroy speakers. Continuous power does.

Please read:
http://www.audioholics.com/education/loudspeaker-basics/loudspeakers-power-ratings-part-iii-the-test-results

(note the woofer under test was an Axiom midrange)

thanks for the info - interesting reading.

I don't see anything in the Z7 manual about the max WPC @ 4 ohms, just @ 8 ohms - is there a mathematical formula to determine this?

 

[MatthewB.]

Oh crap Gene, your correct, I was confusing Bi-wiring with Bi-amping. man now I feel stupid. Please ignore my previous post. Sorry guys. It's a long day at work, and I am tired.