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In Reply to: Biamping requires additional Crossover? posted by Apayne82 on March 26, 2007 at 09:15:39:
is to have one stereo amp per speaker. One channel of the amp drives the woofer and the other drives the midrange and tweeeter (assuming that's the way the speaker is wired from the terminals).The advantages of this setup is that the amp's power supply (usually shared between the channels) is worked less driving only one channel with high power demands (the "woofer channel") so there should be a little more "headroom," and there is no opportunity for cross talk between left and right channels (through the shared power supply of the stereo amp).
The term for this is "vertical biamping."
You might give this a shot and see how you like it.
Biamping with crossovers is a whole 'nother game in that it involves you in fiddling with what the speaker designer considered the ideal crossover point and slope for the speaker. It doesn't seem like there's much point to that, unless you rip out the passive crossovers already in the speaker, at which point, you have put yourself in the speaker design business.
The difficulties that people have integrating subwoofers with their main speakers (an analogous process, since you have to adjust the crossover point and level of the sub) illustrates the perils of this procedure . . . and there's a whole lot less room for error when you're doing it at 500 Hz rather than 50 Hz.
(No, you don't need an outboard crossover to biamp a conventional speaker.)
Follow Ups:
Mmmm, sorry, Bruce,IMO, any worthwhile stereo amp has independent PSes for each channel ... for precisely the reason you listed. (Yes, I know they're generally referred to as dual-mono but that's just marketing bullshit.)
Sharing a PS between channels is just a cheap way of getting the product into a particular price point! :-))
Regards,
You sure about that price point thing Andy? There have been many fine amplifiers of the last 20 years or so that had only 1 transformer. Levinson, Krell, Jadis... Of late, the highly touted Dartzeel. None of these are what I would call cheap. Using separate secondary winding is still using the same transformer, not that I for one really believe that crosstalk of any kind really matters any more.
And Naim too, Oz.I merely pointed out it was a "cheap" way of making a power supply ... this might not be reflected in the price on the amp. And even though they might've been fine amps, they could've been made to be better amps for a bit more manufacturing cost.
And, no I didn't mean shared secondary windings ... I meant two separate power transformers; one for each channel.
Regards,
If you check, there are lots of "value priced" power amps that do not have this characteristic. I'm thinking of power amps from Rotel, Parasound and even amps like the Krell KAV series.I believe that most people who have tried it have concluded that your $$ are better spent geting one decent stereo power amp to run your speakers rather than two crappy ones and "biamping."
If, in fact, you have a pair of power amps that are truly "dual mono" (i.e. from the power cord back), biamping should confer no sonic advantage since the limiting factor will be the amount of power the amp can deliver to the woofer. I supppose you could say that, if the woofer amp clips, you won't hear it because the woofer will not reproduce the high order distortion products the way a midrange and tweeter will.
Hi Bruce,Mmmm, you seem to have moved on from stereo power amps which share one PS between 2 channels to talking about biamping ... which I didn't mention. :-)
Perhaps your post should've followed a different post?
In terms of "most people who have tried it have concluded that your $$ are better spent getting one decent stereo power amp to run your speakers rather than two crappy ones and "biamping" ... yes I've read such posts.
Myself, I've gone from one stereo amp running my 3-way Maggies (Naim 250 - with a shared PS! :-(( ) ... to two Naim 250s passively biamping them ... to driving them 3-way actively with 3 Naim amps ... to active 3-way with 6 monoblocks (which don't share even the PCs!).
I agree passive biamping is of limited benefit but in my system it was better than just one amp. But active is streets ahead! :-))
Regards,
is to have one stereo amp per speaker. One channel of the amp drives the woofer and the other drives the midrange and tweeeter (assuming that's the way the speaker is wired from the terminals).Amplifier crosstalk thing should not be considered a limiting factor any more. With amps regularly having > 80 Dbs of separation and listening rooms of maybe 6 Dbs of separation, if we are lucky... any crosstalk due to a shared power supply is no longer a cause of poor imaging. Provided the gain and input voltage requirements to reach that gain are the same (OK, same amp), the outputs should be the same. If either the gain is different or the input voltage is different to reach full power output, an attenuator of some sort may be needed.
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