Bi-Amping using FMOD crossovers

Eusebio

Novice when it comes to Bi-Amping and just trying to get a better understanding. Reading through countless forums it seems that passive bi-amping is basically useless and the only way to get a positive result is to disconnect the internal crossover in the speaker, using an external XO and then bi-amping.

Could i avoid the disconnecting the internals and using an external XO by using some of these:

http://www.parts-express.com/wizards/searchResults.cfm?srchExt=Mfg&srchMfg=265

Another question (probably dumb so i apologize ahead of time). I have a Emotiva UPA-5 and was thinking of using my Yamaha AVR to run my surround speakers and taking the other 2 channels on the Amp to "bi-amp" my fronts (RTi6s). yes i understand that bi means 2 BUT since those 2 channels aren't in use wouldn't it be just like a separate 2 channel amp (UPA-2)

Jay

[Deleted User]

Hello Jay,
To answer your question most directly, yes they could be used to provide a type of high pass and low pass filtering before amplification. There are a few things to consider:
1). depending upon the speaker system you have you could be undermining the sound quality by eliminating the speaker's internal crossover. One of the things that sets good quality speaker companies apart from lesser ones is the design of their crossovers. Polk speakers, for example, are designed with crossovers that blend the various components, of the speaker, into a cohesive realistic sounding speaker.
2). using the speaker's built-in bi-amp function isn't a waste of time. Depending upon the amplifiers chosen a significant improvement can be obtained. Unfortunately, the concept of bi-amping has been diluted somewhat from the original idea of picking two different amplifiers for their sonic characters. Instead bi-amping for the sake of bi-amping has become popular and isn't really realizing the full potential.
3). those passive in-line filters are approximations of the described filter points. True in-line filters require precise parts selection knowing the input impedance of the amplifiers being used. One size fits all won't give accurate crossover frequencies, unlike the built-in crossover which was developed with specific tweeter,drivers and woofers in mind.
4). if you removed the speaker's internal crossover you would, in all likelihood, void the speaker's warranty and could risk damage to tweeters and drivers. The in-line filters are first or second order devices and could allow too much signal to reach components. Good speakers are designed so that if they are over-driven a crossover component will fail, shutting off power to that section of the speaker. If you remove the speaker's crossover you have eliminated that part from the chain and it is possible the tweeter or driver could continue playing and pose a hazard.
You should certainly check with the speaker manufacturer before removing any part of their crossover.
Regards, Ken

dkg999

In addition to Ken's excellent points, IMHO if bi-amping isn't done with some planning and research involved, it's more fad than sonic gain. I've had RTi6's and unless you were going to use a tube amp for the tweeters and a solid state amp for the woofers there's probably little to be gained. The RTi6's respond well to a good amplifier.

Eusebio

Thank you for the responses. For now I will keep my system as is. In the future if/when i upgrade i might tinker inside the cabinets of the speakers getting replaced.