Idiotic Vertical Biamping Question


I've read a couple of detailed articles on the various kinds of biamping.

I understand vertical biamping to be: amp1 uses left and right outputs to speaker1 (we'll say that's the right speaker); one channel to woofer and one to tweeter; and amp2 does the same, but to the left speaker.

We're assuming a two-way speaker.

Now, I assume that each amp still "thinks" it is sending full-range signals out of both channels. So for amp1, let's say the right output channel feeds the woofer while the left output channel feeds the tweeter. The amp is sending information meant for the left speaker to the tweeter of the right speaker. Same problem occurs in amp2 (but possibly with reversed content going to woofer instead of tweeter, depending on whether the channels are wired identically or in reverse of amp1).

It seems to me this would cause tremendous problems in imaging. So there *must* be something I'm missing; can anyone help me out?

Also, every article I've read discourages bridging stereo amps to make them monoblocks, though the reasons vary. What are your experiences with such a setup? I was specifically thinking of getting another McCormack DNA-.0.5 and having Steve convert both amps to monoblocks, thinking this would be the best performance I could get, but maybe that is not the case?

Thanks for the insight, all.

HC
aggielaw
I currently have both vertical and horizontal. Bass amp, (semi) active xover, and dual amps bridged to mono (Plinius does this easily). Previous setup also had 3 chasis but the uppers were born monoblocks and it used the passive xover of the speakers and a DIY attenuator. The advantage of an active xover is that it allows you to get rid of the passive, parasitic cancers. Nothing to do with limiting the bandwidth going into the amps and whatever they "think". Before considering an active xover, consider the surgery on the speakers and whether the passive network can be approximated externally.

The limited success of either method of biamping only suggests how the complexities are misunderstood, general ignorance, or a lack of patience. Some might say, "if you gotta ask, don't ..." , but that takes all the pain from learning.

Whether a stereo amp can or should be bridged to monoblock is dependant on the construction and the speaker load. Apparently, few should and much of the point is moot if the amps are already balanced (differential).

I agree with Steve that bridging is preferable, if available. If he says it would be good with your speakers, go for it. Often, the output wattage is quadrupled. Many speakers have the crossover point way too high to have any advantage for passive biamping.

Good luck
How's this one for the experts...i'm putting together a system consisting of B&W 801,s series 2, Bryston BP-25 pre amp and 4 Xindac mono blocks, One for the left woofer,one for the right woofer,one for the left mid and tweeter and one for the right mid and tweeter. Should I use xlr connects to the amps or rca from the pre amp? I will have to remove the two wires from the crossover on each speaker. Will every thing work perfectly and give me that power reserve to keep these amps in Class A with a bit of volume. I found that with running just the two monos on these speakers I had to crank the volume control 90% maxed to get the room to shake...lol. No complaint of the sound comming out of the Xindaks...just want more of it. Thanks D.
If you have spent the money to bi-amp your system, my suggestion is to go the extra step and get an electric crossover. In my humble opinion, this produces the best bang for buck upgrade in sound.
The 801`s have a crossover that requiers the high/low wire to be removed which sepatates the frequencies and allows the bi-amping to be done. I'm running the top/high end with the Xindaks and the bass with A pair of Bryston 7B SST`s. XLR for the Xindacs and RCA for the Bryston..only one pair of output XLR on the pre-amp. Wonder why they didn t add two...lol.. D.
Thanks for the input Rf.
I just came across this thread while browsing. Coincidentally, I started vertical biamping my Sony SS M3's with two Rotel RB-980BX's (2x120) just about a month and half ago. Previously, I had been using just one of these. Removing the binding posts and adding the second amp made a huge difference. Night and day. After reading this thread, I ran over and switched them from stereo to bridged mode. The volume jumped dramatically, inversely proportional to the quality change. Ick. The sound was very thin, almost fuzzy. Maybe I need to wire them differently? I'm looking forward to an active crossover. I'm sure this will yield significant improvements.

By the way, the preamp is a Lexicon DC-1 with "Bypass" engaged, no bass/treble adjustment, no Loundness Contour, etc. My source is a basic Sony Bluray player connected to the DC-1 by toslink. I lucked into the Lexicon and Rotels (both needed repair). The speaker purchase was a craigslist shot in the dark that I feel turned out very well. :)