If you Bi-Amp a 4 ohm speaker = Ohms????

Good suggestions, I will check to see if my speakers really require an active crossover or not, but I don't think they do. The reason why I want to use one BEFORE the amp is that I want to reduce the load on the amp by getting rid of the frequencies that the speakers will not produce. I am sure you have seen my other questions relating to bi-amping a pair of Infinity Kappa 9's Putting all the suggestions together I have come up with the following set-up. Almost all of my components are higher-end Yamaha (sort of mid-fi I guess) I have a Yamaha CX-1000 pre-amp with two sets of outputs. One is being run to a Infinity SSW-210 sub (250 watts, 2 10" drivers) The other set I plan on running to a Paradigm X-30 sub crossover. This is due to my Kappa 9's having a 80hz crossover for bi-amping/bi-wire configurations. And the x-30 has 80hz as it's middle high-pass setting. According to reviews and tests the high pass is actually about 75hz. So I figure if I run the high pass out to one of my two Yamaha MX-1000 amps and then to the Kappa 9 crossover I should have a seamless connection with the K9 crossover throwing out just 75-80hz. I will also run the low-pass a bit above 80hz with the same results on the low end. That way the amps are only producing the frequencies that are required. I think it will all work fine. My Ohms??? question is because the Kappa 9's are rated at 4 ohms, but that drops to less than 1 ohm over part of the frequency range. And this is a bit too much for one MX-1000 sometimes. (my second MX is on it's way) I am hoping that by bi-amping I will solve that. Less paths for the power to travel equal more resistance right? I know, I know I really want to get a Sunfire Signature and bi-wire it for a much better result than that Yamahas could ever produce. But that is out of the question for a little while anyway. Someone must have examples of what they have seen once going to a bi-amp set-up. Since my speakers are 12 years old (just bought them used) I don't know if I can trust what Infinity says if I do get ahold of them. I have all the documents and there is nothing that is helpful. I have tried to measure the resistance with a multi-meter, but I never got any results that made any sense. How can I measure what I want to find out?

You don't really need to put the cross-over before the amps if your speakers have an internal cross-over designed for bi-amping. You pointed out that you don't want the amp to see the load (reduce the load), but the load is generated by the speaker, not by the incoming information. So, if the speaker only draws high pass information from one channel, that is the only load the amp sees. The additional low pass information you have sent the amp is just extra information and should really have no effect on the load of the amp (or it's performance). I don't know very much about your specific speakers, so I can't make specific comments, but perhaps someone else with those speakers can be of some help.

The posts above are all correct. Your speakers have a low impedance at a certain frequency and you don't know which frequency, so if you go with the amps per channel approach you are stuck at that freq. on each channel. However, if you isolate the problem to a frequency, and split up the amps over channels you can have a bigger amp take over ath the critical place.

You mid-fi stuff is really excellent!! At one time I thought the Kappa 9's were the best value in HIFI meaning the most drivers and woofer square inches for the buck. Congrats!

To measure with your multimeter you need a signal generator as well. Generate singals from 20 hz to 20Khz (very low power though!! (don't kill the tweeters)) and measure the voltage drop over a 2 ohm series resistor (which gives you current and knowing v=ir you can figure it all out). You will be able to calcualte the impedance per frequency and graph it as well. This will tell you the problem frequencies with low impedance.

From your post, you appear to be getting the program. I recommend to you to give up on your plans. Go high-end. Get a good amplifier and CD player and cables and eventually new speaks (no!). I bet a BAT or Classe or Krell or Ayre with a 24/96 cd player would sound better than the proposed system. You would also not be stuck with more midfi when you decide to upgrade.

good luck and keep trying!