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If bi-amping is so great, why do some high end speakers not support it?

I’m sure a number of you have much more technical knowledge than I. so I’m wondering: a lot of people stress the value of bi-amping. My speakers (B&W CM9, and Monitor Audio PL100II) both offer the option. I use it on the Monitors, and I think it helps.

But I’ve noticed many speakers upward of $5k, and some more than $50k (e.g., some of Magico) aren’t set up for it.

Am I missing something? Or is this just one of the issues on which there are very different opinions with no way to settle the disagreement?

Thanks folks…


128x128rsgottlieb
bdp24's avatar
bdp24
10,085 posts
 

Adding (a) powered sub(s) with built-in x/o filters IS a form of bi-amping, but doing so does NOT replace the speaker-level x/o, which is left in place to divide the signal for the speakers’ (not the subs’) woofers vs. tweeters.

There has been mention here of digital active x/o’s, but there are still analog x/o’s available, for anyone not wishing to turn his LP’s, 78’s, 45’s, tapes, and FM signal into digits. Two reasonably-priced good ones are made by Marchand and First Watt (Nelson Pass), both around a grand. Bi-amping works only with speakers designed to be so used---Maggie 20.1’s, for example, are, 20.7’s are not (just as 3.6’s are and 3.7’s are not, same with 1.6’s vs. 1.7’s).

The pre-.7 Maggies can be bi-amped using an active electronic x/o because their stock speaker-level x/o's are textbook parallel designs, easily duplicated by an outboard x/o. The .7 speakers have series x/o, not so easily duplicated. Any speaker having corrective filters (Zobel networks, to correct for any driver misbehavior) also make bi-amping complicated.

One reason bi-amping can improve the sound of a speaker that has not been mentioned here (I don't believe), is that powering each driver with a separate, dedicated amp prevents the back-emf (electro-magnetic force) that a woofer sends back to the amp powering it can not reach the tweeter (in a 2-way loudspeaker). The advantage of that arrangement should be obvious!

kdude66
1,200 posts
 
O boy still going.
wolf_garcia
6,744 posts
 
My current speakers, Sonist Recital 3s, sound MUCH better biwired, my previous speakers, Silverline Preludes, did not. I discovered this (with the Preludes anyway) after talking to the designer, Alan Yun, who said the Preludes would be "more coherant" single wired…he was right. Biamped (or even tramped) "active" speakers can sound astonishingly good if well designed, and I've used various forms of those in pro audio and studio work, but prefer (for live sound anyway) passive speakers when I have the choice due to field problem solving ease if something goes out. Note that not only are RCAs used in pro stuff, but 1/4" phone plugs are everywhere…strange but true…although I prefer XLRs and Neutrik Speakon plugs whenever appropriate.
avanti1960
1,541 posts
 
bi-amping can be great but it depends on the application.   there really are not many disadvantages for speaker makers except the slight expense to add the additional wiring, binding posts and jumpers.  
the advantages are the ability to have a more dynamic presentation through increased amplifier power, the ability to isolate the tweeters and midrange drivers from the woofer amplifier which may clip at higher volumes.  the clipping of the woofer amp basically becomes inaudible because it is subject to the woofer's crossover.  The midrange / tweeter amp will never clip because of the reduced demand on the amplifier to play those frequencies.  
the ampfliers need to have the same gain or the ability to be level matched.  doing so will not affect the voicing of the crossovers.  
i had an incredibly dynamic powerful sounding system with PSB tower speakers seeing 150 watts on the woofers and 100 watts at the tweeter / midrange, amplifier gain was identical.  the system was able to play much louder and had no audible sense of strain, compression or distortion.  
dkzzzz's avatar
dkzzzz
124 posts
 
I had my first bi-amping epiphany today. I never believed it is useful to do with just two dumb power amps. I was bored today and connected two integrated amps with tone controls to my speakers. I let Ayre run my treble and then vintage Marantz to run my mids and bass. I adjusted tone controls for more bass, adjusted balance since LP was playing uneven in volume. I was shocked how much more decent bass I have extracted from my speakers that were always light in that department. The difference is HUGE. So if you want to play around with bi-amping try two integrated amps with at least VOLUME control, so that you can adjust the sound for the type of music you are playing. My speakers came alive after 8 years for the first time. I listened to some classic jazz and  Leonard Cohen, it sounded so, so good.... I am going to do the same to Wilsons when my Luxman returns from recap service.
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