Help to find an inexpencive active Xover


I want to experiment with bi-amplification using my DIY passive preamp. I have Totem Forest loudspeakers. For midrange/bass I want to use my Bryston 3b-st and for tweeters I want to use Moretto tube mono 15W/ch class A power amplifiers.
First of all, I've never had any experiences with active Xovers so I need someone to tell me what to start with and what will be the reasonable amount to spend on that device.
Secondly I want some useful theoretical preliminary discussions to define all advantages and disadvantages of an upcomming in my head experiment.
And finally I'd like to know anyone who's ever used bi-amplfied setup for 2-way speakers.
128x128marakanetz
I've used active bi-amp with Martin Logan Monoliths. I'm not sure the Totems are suited for active bi-amping. They need to have direct inputs to the speakers for active bi-amping to be effective. This differs from merely having 2 sets of binding posts for top and bottom end. In many cases these binding posts still go through an independent filter for each speaker. They are designed for bi-wiring and may be used for passive bi-amping (meaning there is no active cross-over). In passive bi-amping you almost have to use the same amplifier for top and bottom end.

The first thing I would do is check with the manufacturer or dealer and find out if these speakers are recommended for active bi-amping. Then find out the recommended cross-over point and slope. If so, there are several very good active cross-overs on the market: Bryston, Threshold, and Marchand. I'm using a Bryston, but have heard the Marchand is excellent and is a great value. A new cross-over will cost from $500-$1100--but if you can find one used you will save quite a bit. The used ones are likely not to be the right cross-over point or slope, but you can buy a card for most of them (new) that will have the right cross-over and slope. If you are looking to buy a cross-over used, check the model and call the manufacturer and be sure you can get the card or whatever is needed to get the right cross-over point and slope.
See http://www.marchandelec.com/ for inexpensive effective active crossovers.
Well, here's my experiences thus far with with bi-amping 2 way monitors....First, what usually happens when you take the jumper out, and try to do bi-amp with most 2 way speakers I've encounterd, the speakers seem to sound much stonger and more dynamic overall, but at the expense of a usually forward (sometimes bright) sound altogher !!! In the end, I've found the brightness or forward pressentation a little to agressive and unnatural sounding. It appears that most 2 way's have a better balance, probably due to the way it was designed at the crossover (assuming most people are going to use "non-biamped" from the designers standpoint)!!Actually, I think this has a lot do with the fact that tweeters are more effecient(?) than the woofers usually, and need some attenuation overall...which my attemps have not adressed (I guess there's normally an attenuation at the crossover to accommodate this?). My attemps have involved identical amps, usin the existing internal "passive" crossovers, and haven't worked basically! Although the speakers sure sounded a heck of a lot more powerfull and dynamic!!!..which is alluring for dynamic music and soundtracks and such. 3 way designs usually due much much better overall with biamping (passive that is) than 2 way's!! Infact, I recommend everyone try "passive" biamping (using internal crossover) with 3 way's at least once!!!
However, just because my attemps at "passive" bi-amping have been unsuccessful, doen't mean that others would! If you try different power amp combo's (as your suggesting) perhapps you could get different results (however you'd need to volume match the amps probably some how!..?)
In your situation however(active biamping), using an external crossover(with adjustable gains for each output) with a 2 way could prove most interesting!...and fun. I'd bet you get a very very dynamic sound which, if you can get the balance right,
I'm certain would sound really really good!...assuming a quality effort, drivers, and electronic of course!
Actually, I've been toying with the idea of using an active set-up with some 2 way's I have pressently!
I can't tell you what active external crossover (inexpensive) to buy, nor have I experiene with any cheeper ones thus far. However I hear the Bryston 10b(?) crossover is supposed to be very good for not too too much money!...? I don't think that their amps and such are world beatters or anything. But the crossover is supposedly Stereophile class "A" rated design (if you go by any of that...?), and is basically a simple component, which can be fully adjustable for crossover points, slopes,volumes, etc. And, external crossovers are supposed to have a much greater advantage sonically than internal "passive" networks!....what I've heard from designers anyway.
I think you can find used Bryston 10B's on the net at times, going for around $700 (new $1600). It's worth a shot, and I bet you'd get good results. Good luck, I'm going to try this as well!...only using identical amps on top and bottom first.
The Marchand design is quite flexible, reasonably priced and built pretty well. It also offers a "Q" adjustment, which controls overlap between the drivers at the point of crossover. As such, you can "fine tune" the system to a much greater extent than you can with other crossovers that lack this feature. I own and have been using an upgraded version of the XM-9 three way crossover with great results.

As to the benefits, you will have MUCH greater dynamic range, increased detail, etc... The results are NOT subtle when properly done. You have to be able to DIRECTLY drive the speakers though with NO crossover circuitry for best results. The only thing that might be acceptable would be some form of impedance compensation or notch filter.

I too would suggest contacting the manufacturer of your speakers to find out if this is a viable plan BEFORE buying anything. Vince is a nice guy and will work with you as best possible. Sean
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You might need a tube crossover, for your amplifier is really fast sounding, check "www.space-tech-lab.com" for different models, they made real good sounding tube equipments with one fraction of market price.
I have try a lot of bi-amp, tri-amp and quad-amp combination with different active crossover, but tube crossover is my final decision to go. The most important points is after crossover, the phase shift is different for different freq band, in order to compensate the phase shift, you should test all the +/- combination of all channel in order to get the best phase coherance. The best way to play around with a active crossover system is to build you own speaker set, each channel with different box, then you can adjust the different phase relationship by adjusting the relative position of different channels.
Hi
Andre from e-speakers.com is selling a Mc MQ104 for 199.00
he is a very honest gentleman and well known audiophile. Tell him Aditya sent you
I have Bryston 10-Bs in A 3 way mono system. Outstanding performance. I agree with the above that you'll spend between 500 and 1100 new....but used ones are always available. Good Luck......