built-in Xover during active bi-amping.


Does it make a sence to remove built-in crossover from the speaker during active bi-amping(with active crossover)? How these two crossovers interact together if built-in isn't removed?
128x128marakanetz
The answer is definitely system dependent.

I actively bi-amped my B&W800's. I removed the bass low pass filter completely, and rewired my mid/high filter network. The design was done for me by Dan D'Agostino of Krell fame.

YOU SHOULD KNOW WHAT YOU ARE DOING BEFORE MAKING CHANGES TO A GOOD SPEAKER SYSTEM. I didn't, but Dan D'Agostino did.

Richard
Hi Mar:
I agree with Rich that you have to know what's going on but you do NOT have to be a mod superstar ala D'Agostino or
something to bi-amp your system. Like Rich, typically your low pass passive filter remains.

I'm not certain what system Greg is referring to and I am not familiar with the Bryston unit he talks of but, in any event, I do not see how you can "get away not removing the crossover" for the mid to high frequencies. Getting the passive filters out of the way at that point (between amp and speakers) is the main advantage of bi-amping. Whatever system you have you cannot keep the entire passive XO system in (and working) and get the advantages of bi-amping. There is a good general discussion of bi-amping at Rod Eliot's web site. I suggest you read that Mar. It is a great improvement when done properly.

Rod Eliot's article on bi-amping is @ www.sound.westhost.com/bi-amp.htm

Maybe Sean or some biamp guru will pipe in.

Sincerely, I remain
As I mentioned, you will not see the full benefit nor will you lower your speaker's resale value unless you remove the crossover. This approach will always generate debate much like vertical biampping, since it uses ideas from both active and passive biamping. I would say there is a continuum of sound quality/cost which runs along these lines.

1) Standard setup, one channel per speaker
2) Vertical biamping, two channels per speaker Need more amps
3) Active/Vertical biamp approach (This one) Need more amps and a unusual crossover.
4) True active More amps, crossovers and speaker mods.

There are a few who stoutly maintain that passive biamping has no effect and will not improve your sound, since I've heard it improve sound, to the point where I bought another amplifier for that improvement, I disagree with them.

There are two main advantages to an active biamp over other forms of biamping.

1) "Getting passive filters out of the way" and thereby getting rid of all the nastiness like phase shifts and frequency response problems which passive crossovers are noted for.

2) Reducing the frequency range of the signal each amplifier channel is seeing. With a vertical biamp, the amplifier still sees the full frequency spectrum and attempts to reproduce it even though the portion of the spectrum which is outside of it's section of the speaker does not produce power since it is driving infinite resistance.

You will not get the first benefit with the approach I suggested, however you will get the benefits of reducing the frequency range each amplifier is seeing, and keep it from trying to reproduce the singal which will not be heard. Exactly how much of a benefit you will see is somewhat system dependent, since it relies on the original crossover.
Greg
BTW - The Bryston I was referring to is the 10B, it's up on Bryston's web site at www.bryston.ca.