Active crossovers

As has been touched on above, the "purist" solution for the VR4 is to passively biamp. Putting an active xover in the signal path is going to introduce unnecessary processing. The top and bottom modules of that speaker already have high pass and low pass filters (respectively) that allow a full-range amp to drive each. The only "compromise" that will be needed is some sort of signal splitter at the output of your preamp, unless you are luck enough to have 2 outputs on the preamp. I would strongly advise against trying to bypass or modify the internal filters of the VR4, which have already been optimized for module integration.

Interesting, Ral, Albert sent me an email staing as much.
The trick then, is to find amps with similar sensitivity.
So now, to look for an SS amp to match 99 magnums?

KP

There is an active crossover, that can be ordered in a 2-way or a three-way configuration,from the Australian company
Symfonia.It´s called the Symfonia AC 1, and the company
has a testimony from Duntech on their website,that Duntech
finds the AC 1 superior to the Krell KBX.
I find this crossover interesting, but actually, I have
sent a mail to Symfonia three times,without recieving an answer!
Regarding the general question on active crossovers,I think
that it depends on several factors,e.g. the need for high
sound pressure level requirements, synergy with other components,knowledge by the user etc, if the end result is benificial compared to a passive solution.
But I agree to the statement, that it´s generally a good thing, to have a active crossover for the lowest part.
I can honestly say that by using this approach in my current loudspeaker-project, I have,
with some tweeking, succeded to get possibly the best
bass reproduction that I have heard..

KP: Yes, matching the 2 amps will be challenging. If you can find out the overall gain of the Rogue that would be a good start. Most solid state amps will have gain in the 28-30 dB range. Might be interesting to see what Albert uses for his SS/tube combo. Even with gain and sensitivity matching, a tube amp can still sound "louder" than the SS. However, given the low xover point on the VR4 (150Hz) it shouldn't be terribly noticeable. By the way, I have been thinking about the same approach to driving the VR4, if I decide to buy them (I'm still auditioning some locally). Good luck and please let me know what you find.

Ral, I will.
I'm looking for ss amps with adjustable gain; should make life easier.

KP