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What’s the Right Power Amp Ratio For Bi-Amping?

Is there a “golden rule” or rule of thumb when selecting amplifier power in a bi-amp setup? It seems to me that the power should be apportioned according to the demands. Since most of the energy consumption  in sound reproduction is by lows, it stands to reason I should use a much more powerful amplifier for lows than highs, but what ratio of power? 2:1? 10:1? Is there a wrong answer?
128x128sleepwalker65
pauleladue
15 posts
 
I am using one stereo amp on each speaker. Left for mid highs and right for bass cabs.  The meter is always higher on mid highs.  Same amp.  Crossdover point between upper bass driver and lower mid driver is 230hz.
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almarg
9,670 posts
 
Thanks, Pauleladue.  That's an excellent data point, which most of us wouldn't be able to provide and which is consistent with what I said.

Regards,
-- Al
sleepwalker65's avatar
sleepwalker65 OP
832 posts
 
What units are the meters marked in? Watts or VU or ?
sleepwalker65's avatar
sleepwalker65 OP
832 posts
 
Update:
I’ve located and purchased another NAD 2700 amplifier, so I’ll have a pair of identical amplifiers.

I’ll now have 3 options: vertical bi-amp, horizontal bi-amp, or bridge and power left and right separately without bi-amping. Vertical bi-amping seems to be the preferred way, as mentioned by @racamuti , @almarg and @georgehifi, so I’ll try that first.

Bridging seems too extreme by the way, as I’d end up with the capability to produce 400 watts per channel, probably ten times what I’d ever need during normal listening sessions with my relatively efficient Energy Reference Connoisseur 30 speakers in my 12’x12’ listening room.

I will experiment with shorter speaker cables, from the 8ft 12 gauge cables I’ve used with the 3225PE/3020i setup, I’ll be able to go to 3ft 12 gauge cables with the 2700s sitting beside the speakers. I’m not expecting any audibly noticeable improvement, but maybe I’ll be pleasantly surprised.

Thank you everyone for your input! This is is going to be fun!
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georgehifi
10,312 posts
 
Bridging seems too extreme by the way, as I’d end up with the capability to produce 400 watts per channel, probably ten times what I’d ever
Not only that, but also sound quality is worse. As everything measured parameter that makes an amp a good one takes a hit when you bridge. The only plus you get is the extra wattage when you bridge, and if you don’t need it, then you actually go backwards in sound quality.

EG: Bridging Amps
CON’s:
Higher distortion
Lower current
Lower stability
Inability to drive as low impedances
Lower damping factor
Higher output impedance.

PRO’s:
Higher wattage.

Cheers George
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