external crossover when bi amping?


Is an external crossover needed when bi amping speakers? What happens when you dont use one? How does the internal crossover work in a 2 way speaker when fed by 2 amps and 2 cables?
nerspellsner
Most all speakers have a x-over within. It controls what goes to what and cut-off points.If you biamp with different amps the internal x-over must be removed from the equasion.-The output of the amps will be different. The volumes won't match.---Biamping with 2 of the same amps allows you to still use the internal x-over.
George: "If you biamp with different amps the internal x-over must be removed from the equasion (sic)."

Absolutely not correct. Biamping with the existing passsive crossovers--and 2 identical amps--is the easiest way to do it. Even if the amps aren't identical in gain/sensitivity, it's STILL the easiest way to biamp, as one merely needs a gain control on the more-sensitive amp. Using the passive crossovers also retains all the impedance-correction and other equalization networks the speaker designer worked perhaps very hard to perfect.

Ner...:
1. An external crossover is NOT needed when biamping.
2. Don't quite know how to answer this. Perhaps all the other info here will answer it for you.
3. The same way it works when you feed it with one amp and one or 2 cables.

Biamping can be very complex and difficult to perfect. SOMETIMES it brings fine results. I suggest you start with biwiring--you'll need it anyway if you decide to biamp.

BTW, it's 'biamplify' or 'biamp' and not 'bi amp' or 'bi-amp'.
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Perhaps some further explanation is needed here. If you have a two way speaker with one pair of binding posts and an internal crossover, of course, then I don't see any other way of biamping than to disconnect the tweeter and the woofer from the crossover and then connect each directly to an amp. How else can you get one channel to go directly to the tweeter and the other channel to the woofer if everything is still going through the original inputs? I have always thought that the purpose of biamping was two fold:
1. to place the crossover before the amps, and
2. to give each driver it's own power source.
Which means, you would need an external crossover.
Are we confusing biwiring with biamping?
Sonny
Sonny: "If you have a two way (sic) speaker with one pair of binding posts and an internal crossover, of course, then I don't see any other way of biamping than to disconnect the tweeter and the woofer from the crossover and then connect each directly to an amp."

In order to biamp or biwire such a speaker, one 'merely' has to separate the inputs of the 2 sections of the crossover. Sometimes that's easy; sometimes it's not.

The goals of biamping are many but do not HAVE to include eliminating the speaker's crossover. As I said earlier, many crossovers have impedance-contouring and/or tonal-response-equalization networks in them that the speaker's designer may have worked very hard to perfect. Driving the drivers directly eliminates the benefits gained by these networks. Of course one can deliberately eliminate such networks, but one should realize that one is changing the sound of the speaker, perhaps dramatically. If there are no such networks in the crossover, then it's much easier to replicate the response of the passive crossover in an active crossover.

There are no easy answers in biamping. Still, the easiest way to effect it is to use the 4 channels of 2 identical amps to drive the biwire terminals of the speaker. The next-easiest way is to use 2 different types of amplifiers...say, a solidstate amp on the bass and a tubed amp on the MR/treble...but one almost always has to have a gain control on the more-sensitive amp to tonally balance the system.
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Thanks for your input on this topic. I asked this question because I have an extra amp and wanted to try biamping. The speakers in question are 2 way monitors with 2 pairs of binding posts. I have replaced the metal jumpers between the binding posts with 14 gauge 65 strand OFC speaker wire. This resulted in a brighter sound, but a little to bright with some sources. Now on a rainy day I want to try biamping. The point of level matching of the woofer and tweeter is one that I overlooked. How do you get this right? Is it trial and error or can you use a sound level meter and test tones? I have read that some people only biwire (not biamp) their speakers to seperate the high and low frequencies in the cables feeding the speakers. If this is done it seems that you would have to use an external crossover and bypass the internal crossover. What would be the point of biwiring with 2 pairs of cables connected to 1 pair of full range (20hz to 20khz) binding posts on an amp? It seems that you would only be duplicating your existing connection. You would still have a full range signal going through both sets of cables. Am I missing something in this equasion?