Active crossovers

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

Matching two amps is trivial.

There is no matching to be done, other than level setting. Just about every electronic crossover has level adjustments for every band.

Regardless of the "gain" of an amp, when you increase the input by 3dB, the output goes up 3dB. So, all you have to do is to put a level into amp 2 that when compared at the speaker output using pink noise gives the *same* level on your SPL meter as does amp 1. Of course, your ear will be the final arbiter of the precisely perfect relative levels.

If your electronic xover does not have level controls, and your amp does not either, you can either build a fixed pad into a small box - after measuring the dB difference with no pad. Or you can buy an after market in-line adjustable attenuator box to put in line with the amp that is "too loud" to reduce its level. Alternately, you can drill some holes into your amp and put a small rotary switch with MF resistors and make your own attenuator built in,or just put a decent pot there... I do that all the time on Phase Linear 400s that are used as subwoofer amps from time to time (on the front panel of the PL400, to match the PL700).

All done.

_-_-bear