biamping and curent

Good question! This is my understanding of "bi-amping" Bi-amping is using two (2) amps running in stereo to amplify one (1) pair of speakers. Your speakers must be set-up to be bi-wired. Generally on bi-wired speakers, each speaker has two pair of binding posts. One pair for hooking up speaker cables for the bass woofer and another pair for the midrange/tweeters. The idea is to run two amplifiers, both in stereo. One amp will power the bass woofers of each speaker and the other amp will power the mids/tweeters. You will need two pair of speaker cables in this configuration. Impedance is a little tricky. In general terms, nominal impedance is the combined average of drivers in a speaker. If the bass woofer is 4 ohms and the mid/tweeter is 8 ohms your nominal impedance is 6 ohms. In this scenario, the bass amp would be driving a 4ohm load and the amp driving the mid/tweeters would be driving an 8 ohm load. Bi-Wired speaker cables are used when you have one amp driving a pair of speakers that have b-wire connections. The amp end of the speaker cable will have one negative and one positive spade while the speaker end of the cable will have two pair of spades, two positive and two negative. I hope this helps.

Interesting post Bill. I'm not quite sure what the "implied" misunderstanding in my post was as you said the same thing except for the electronic cross over and I was trying to keep things simple to be helpful. Your recommendation for testing the driver impedance load with a volt meter is not such a great idea. The impedance load of all drivers will fluctuate given the Q and free air resonance of the driver. The impedance loads stated by driver manufacturers are averages. A given driver may have a nominal impedance of 4 ohms but at 500 Hz it might have an impedance of 6 ohms. Someone testing a driver as you describe could easily come to a very wrong conclusion. Internal cross over and wiring topology can further impact the circuit impedance load. The nominal impedance for bi-wired speaker circuits are usually listed in the manufacturers spec sheet. I would strongly recommend using those parameters. Your idea of being careful hooking up two amps for bi-wire speakers is interesting. I would think that having these two circuits sharing a common ground could be possible, but I can think of no reason why they would. I have never seen this applied to any speaker, internal crossover or wiring topology I have ever heard about or seen! That doesn't mean it doesn't exist, but if a speaker manufacturer did such a thing, it certainly goes against industry standard practices. Sounds more like the boogie-man than reality to me.