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Who Here is Vertical Bi-Amping?

I recently tried vertical bi-amping and I am very impressed with the results. For the record, I am using “vertical” to refer to using two stereo amplifiers (one amp per speaker) where each amp uses one channel for the midrange/bass driver(s) and the other channel for the tweeter. I am using passive crossovers between the amps and speakers.

My first impression is that there is a noticeable increase in detail and a large reduction in treble harshness at higher listening levels. This makes sense to me because now the tweeter is independent of what the midrange/bass driver is doing. (Technically its “independence” is equal to the channel separation spec of the amplifier.) When the mids call for lots of power which can stress the performance of that channel, the tweeter performance isn’t affected. 

After reading what I could online, I was hesitant to even try vertical bi-amping since I saw lots of mixed reviews on bi-amping in general. I decided I had to try it after reading this post on another forum by Mark Donahue of Sound/mirror Inc. (no affiliation):

“...We have been vertically biamping the speakers here in our mastering studios for 25 years and have yet to find a monoblock that delivers better performance than a pair of stereo amps.
Going back almost 20 years we were looking for a big solid state amp to drive the brand new at the time B&W 801 II. What we found at the time was that the larger monoblock amps from B&W (MPA-810) and Threshold (SA-1000) did not sound nearly as good as the similar stereo amps in a vertical biamp configuration. Every couple of years we would try out the new big monoblock de jour (Krell, Spectral, Cello.....) and every time we found that the stereo sibling of the big monoblock yielded better imaging and lower overall distortion.
Recently we went through the entire routine again. I finally had to retire my five trusty old Threshold S-500 series II due to the need for true balanced inputs. I tried the Classe CAM400 and was underwhelmed with the imaging and clarity. I then replaced them with the (Less Expensive!!) CA-2200 stereo amp and the difference was shocking. Better imaging, better impact and smoother frequency response from my Dunlavy SCV’s.”

I’m very glad I tried it as my system is sounding much better! Does anyone here vertically bi-amp their speakers? If so, what has been your experience and do you find it better/the same/worse than monoblocks, stereo amps, horizontal bi-amping, etc.?
128x128mkgus

Showing 4 responses by mkgus

mkgus's avatar
mkgus OP
324 posts
 
Seems like there are pros and cons to each.

Vertical: Each amp is only asked to drive one bass driver (the majority of the load), very high channel separation similar to monoblocks, easier to integrate than horizontal bi-amping, unbalanced rails an issue?, etc.

Horizontal: Can use 2 separate amps that are optimized for low and high frequencies, lower channel separation than vertical biamping or monoblocks, challenging to integrate?, etc.

Bi amping is similar to bi wiring. You are simply running the power of the amps through the exact same internal crossover network of the speaker. This serves little to no benefit.

The benefit I see with vertical is that the mids and tweeters have their own channels of amplification and in a well-built amp, one shouldn’t effect the other. Asking a single channel in an amplifier to deliver massive wattage for the mids while still being delicate enough to reproduce good highs seems like a tall order. With vertical, even if they share the same power supply/transformer, there should be some benefit as the channels are isolated from each other. That’s my thoughts on the subject and my listening impressions line up with that.
mkgus's avatar
mkgus OP
324 posts
 
Knotscott, that’s an interesting concept with the “mismatched” tubes. It makes a lot of sense.

I started with a stereo amplifier and then went to two stereo amplifiers in monoblock configuration (only using one channel on each amp). I really appreciated the step up from one stereo amp to “monoblocks.” It was a big improvement. I wasn’t there long before I tried vertical bi-amping and finding that I really like the results.

I use left and right channel tube preamplifiers. I could definitely try something somewhat similar to what you described with your stereo amp “mismatched” tubes concept. Thanks for the suggestion.
mkgus's avatar
mkgus OP
324 posts
 
Also, I’m beginning to see why my previous internet searches didn’t bring up as much information as I was looking for. Doing vertical bi-amping with active crossovers is not for the faint of heart and requires lots of knowledge and experience. As such, there probably aren’t that many people doing it, relatively speaking.
mkgus's avatar
mkgus OP
324 posts
 
Thank you everyone for sharing your systems and experiences with bi-amping. Some of these systems that use active crossovers seem high tech. Very impressive. Thank you boomer for offering to let me hear your system!

One question I have for those who use electronic crossovers, is it a requirement to convert the signal to digital to do the processing? If yes, does that affect sound quality at all? I’m thinking that doing an extra conversion step to digital and back to analog could be detrimental, but maybe that’s not how you do it or maybe it’s not that detrimental. The DSP I use for my subwoofers, for example, allows for it to be hooked up to a computer for streaming so it could be the source with no extra analog/digital conversion step. 
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