Anybody have an actively multi-amplified system?


Hello,

I am one of the very rare breeds that has a fully active system, 6 Jeff Rowland monoblocks running Klipschorns with an Accuphase F-25V electronic crossover in front of the amplifiers, and the passive crossovers taken out of the speakers. It sounds absolutely phenomenal, like nothing else out there. I've been in the business 35 years and have yet to meet anyone (in home audio at least) who has done something similar. It's done all the time in pro audio, yet nobody talks about it for home use. It's widely known that an actively amplified setup simply IS better than any passively crossed over speaker, since the dividing is done before the amplifier, each amplifier only amplifies a certain frequency range, and then the output of the amplifier is connected directly to an individual driver with nothing in between. If anyone has such a setup, is interested in learning more about one, or wants to throw in their 2 cents, please do! It's about time we did talk about this, and I can't believe in all these years more companies haven't actively (pun intended) embraced this type of setup. Also, if anyone has crossover cards for an F-25V crossover, please let me know!!!
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Yes, this is how I've been running my Magneplanar 1.6qr speakers for the past 5 years or so. I built a line-level buffer/crossover using the Linkwitz Labs MT-1 board which lets me duplicate the original crossover frequencies for the bass panel vs. the tweeter panel. I have two Harmon-Kardon Citation-II stereo amplifiers, thus 4 "channels" where each amp output is wired directly to the drivers (soldered directly with no connectors at either end). The amps are bi-amping 'vertically' where one channel receives its signal from the treble part of the Linkwitz X/O and the other channel receives its signal from the bass part of the X/O.

Getting rid of the speaker crossovers was a huge improvement, both in terms of clarity and pace as well as delivered power. The stock crossovers soak up a lot of power! In a typical third-order crossover like Magnepans, as much as 75% of the power is wasted in the crossover (or so I'm told). My speakers are MUCH more dynamic run this way than with speaker-level crossovers.

So, I agree with you that this is a superior way to drive speakers. The Linkwitz Orions fit this philosophy as do the Sandersound 10B speakers or the Emerald Physics speakers with Behringer crossovers. Then there's the whole single-driver camp using Lowther's etc. with no crossovers.

That said, there are many fine designs with creatively tuned crossovers that will NOT sound good driven directly. In particular, phase relationships between drivers and the perceptual effects of phase coherence adjustments are critically important to many designs. Not something to just be applied to any old speaker!
This category includes all modern Meridian systems which also incorporate room correction.
I like to run active xovers for woofers and subwoofers but find them impractical against passive xovers for higher frequencies such as the tweeter/mid. A lot has to do with the size and cost of the xover components and assosciated phase shifts. A 0.68 mH air core coil (roughly 2.5 kHz @ 4 ohms, 2nd order) is lot less intrusive than a 6.8 mH iron core (approx. 400 Hz @8 ohms). And that's not getting into guage and cost.

Most ribbon tweeters require some sort of xover, or at minimum, a capacitor for protection.
Ya sorry it's my first one so it got duplicated from going backward and forwards with the browser. Sorry all.