use bridged mono and bi-wire or use stereo mode and biamp? pros & cons?

[dpolmann]

I have N804's and HTM-2 up front. I acquired three amps second hand, to use one for each speaker. On advice of my B&W dealer, I set up the amps each with their own custom-made Y-cable. The left pre-out goes to one amp in both L & R channel. That amp is wired to the left N804 in a passive bi-amp mode. The right pre-out and the center pre-out each go through Y's to their own amp L&R channel, and are similarly wired to their respective speakers. The amps I am using are all Rotel RB980-BX at 120 wpc. NEWBIE QUESTION: I see lots of threads suggesting more power is better, but I am perplexed about the classic question of passive bi-amp vs. bi-wire (I've read about it, and you'll probably agree it's just not obvious). Given that I COULD switch each amp to bridged-mono, getting 380 watts each that I can dedicate to each speaker, SHOULD I? Bi-wire it? Will the performance characteristics of the amps degrade (lower damping factor, higher distortion, other)? Does anyone have experience with this type of comparison? I'm sure to hear "try it and see how your ears like it". OK, I could do that. ops: But, I am hoping for feedback from someone other than my local salesman (who by the way doesn't work there anymore) and I'm sure you guys have good thoughts on this! Thanks in advance for your patience and kind words.

[basementjack]

I'm not the best one for advice, since I haven't yet tried what you have. However I will add one more piece to the biamp puzzle.

the 804's have two crossover points: 350 and 4000hz

I think the two input terminals are split on the 350 crossover.

You could install a few inexpensive inline RCA Crossovers to reduce the amount of work each amp has to do. The freqency of each does not need to be exact (I would choose two that overlap - one that cuts off everything above 500hz for the amp that feeds the low frequency, and one that cuts off everything below 200 for the high frequency)

Such as :

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=266-260

(connected to the amp that feeds low freq)
and
http://www.partsexpress.com/pe/showd...number=266-278(connected to the amp that feeds high freq)
They cost about $25 a set.

If you wait long enough, I'm sure I'll try this on my system and I can let you know the results...

[dpolmann]

not-so-passive bi-amping?

basementjack - thanks for the thoughts, and the Parts Express suggestion. Seems like you are suggesting one step toward active crossovers in front of the amps, in that this approach of high-pass and low-pass filtering cuts off the frequencies that are "wasted" in each instance. I was unaware that such filters were available in-line RCA, and they look very convenient. Question of course is whether or not they are of high quality compared to the electronics otherwise in the setup, or would this be adding a "weak link" to the chain? :evil: I gather you don't expect any degradation from these links in the chain, as you expect to try this tweak yourself. I am simply not familiar enough with this product, and don't want to inadvertently add a new problem while creating a solution. :E Thanks for any additional thoughts from anyone out there!

[Jurgen]

I’ve tried both (bi amping and bridging). In my setup (4 ohm speakers), there was absolutely no doubt. Bi amping was way better: night and day difference. I haven’t tried active cross-overs, and although I can imagine that it is better I’m not really tempted to do so. (passive) bi amping really works for me and it is a definite improvement over single amps.

Jurgen

P.S. do a search on the subject in this forum. There has even been a poll by bing fung regarding bi amping.

[Andrew Pratt]

More often then not you'll find bridging amps increases noise and distortion so you're likely better off passively bi amping. I've used those inline RCA filters on an old subwoofer but I'm not sure I'd want to put one inline with my mains...but they're cheap enough it would be an interesting test.

[dpolmann]

Thanks!

I appreciate all of your responses. Very helpful and thought-provoking.