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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

Showing 2 responses by dan_ed

dan_ed
2,451 posts
 
S7horton got it right on the money about sending only one channel to each amp. You either need the y-adapter or two sets of ICs.

I also agree with Eldartford about the effects on the power supplies when running the amps in bridged mode. But you need to remember that you are effectively cutting the load seen by the amp in half when running amps in bridged mode. The effects of pulling more on the power supply from one side vs. the other as with the vertical connections can be compensated for by periodically switching the side that drives the woofers. In my brief experience with bridging I have found that the amps run hotter and it just doesn't sound as good. This is very much dependant on the amps you're using. If the amps can be converted to true monoblocks, then you will probably get good performance from them. Check with the manufacturer of what ever amps you're thinking of using and asked them what they recommend.
dan_ed
2,451 posts
 
Hi Aggielaw,

Yes, monoblocks would be connected so that each block would drive a singe speaker, or channel. This is also how it would "look" if you were to run two amps in bridged mode with each amp acting as a monoblock and running a single speaker. Both of these configurations only require a single IC connection from the pre to the amp for each channel, so it is simpler to connect. What I have experienced with the amps that I have tried running in bridged mode is that the soundstage would lose depth even though there was plenty of power. Now, monoblocks are different because their power supplies are built and integrated as a single unit. They are build for the express purpose of driving a single channel. Of the 4 or 5 amp builders who I have asked about running their stereo amps in bridged mode, all have said that while their amps had the current supplies to do it they recommended running them in stereo mode to get the best sound. (Send an email to Steve, I bet he says the same thing.) I have found it fairly easy to confirm this after listening to both configurations using the same amps. So it really is a matter of what amps you're using and what you're preferences are, assuming the amps you're using have the current capabilites that may be required from driving that 4 ohm load that is now seen as 2 by the bridged amp.

Bi-wiring is completely different and is dependant only on how your speakers are built. I suppose the cables used could also be a factor. There can be a benefit from bi-wiring, but in my experience the gains made from biamping (or dualamping for Eldartford) are much greater than the gains from bi-wiring. Also, with biamping you can get the amps very close to the speakers using longer ICs and keep the speaker wires very short. Another sonic benefit I have experienced. As always, YMMV.

Dan
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