Thu Mar 18, 2004 10:02 am by govcon
From what you're describing, you're talking about biamping and not biwiring. Biamping is the process of using dedicated amp channels to drive specific portions of a speaker. In a two way design, you have an amp channel drive the tweeter and another amp channel drive the woofer. Usually biamping is done with stereo amps. There are two ways of setting up a biamp configuration with stereo amps. For biamping, you would ideally have two stereo amps. In horizontal biamping, you use one stereo amp to drive both woofers in a speaker set. The other amp is left to drive the tweeter/midrange. In vertical biamping, you use one amp to drive one speaker solely. So one stereo amp would be dedicated to drive a specific speaker with one channel dedicated for the tweeter/mid and the other for the woofer. Vertical biamping is the best configuration but REQUIRES two identical amps. The use of vertical biamping spreads the biggest load which is the woofer across two power supplies. With horizontal biamping, the woofers are causing a signicant load on one stereo amp. Horizontal biamping is a bit more forgiving in that you can probably use different amps to set it up. The issue when you use different amps is to ensure proper gain matching. Also, biamping has two other flavors....passive and active. Passive biamping is when you leave the speaker's internal crossovers tied in after the amps. Many argue that passive biamping isn't really biamping and that there are no benefits from doing this. Active biamping is when you disable the speaker's built in crossovers and add an external crossover BEFORE the amps. The crossovers filter out the frequencies before the amp sees them thus increasing the amp's efficiency. Active biamping is more complicated in that you need to modify your speakers to be wired directly to the amp's output and you need to be really knowledgeable to configure the external crossover to match the specific driver's characteristics. The external crossover can also come in two flavors: passive and active electronic. The passive type is just like what is in your speaker. The active electronic crossover provides more flexibility in that you can usually change many of the crossover characteristics for a specific pass band.
Me personally, I've played with vertical passive biamping and like the results. The biggest change I've noticed is that bass is more extended and authoritative. Also, I can crank my system to louder volumes without any audible strain.
Biwiring is just using specific type of speaker wire that is "optimized" for a specific frequency range. There are other explanations for why people think biwiring is beneficial. Personally, I tried it and found that it wasn't that great. I got a cable that was basically two speaker wires in one jacket from Monster Cable. The one end of the cable was single terminated while the other had the dual connections for the tweeter/mid and woofer. Modern amps have the ability to be biwire ready where the amp has 2 sets of binding posts per channel. In this case you would get two individual sets of speaker cables to achieve biwiring. The new Sunfire amps have this configuration. Sunfire recommends that you use the current source as the output to drive the tweeter/mids because the output has a 1 Ohm resister tied across the output terminals to simulate more of a tube sound.