What is "biwiring"?

Audioqest calls it single or double biwiring when using a single or a double cable. Most of AQ's speaker cables use multiple conductors of different gage, which make it fairly easy to single-biwire. Their most-common conductor sizes are 16-, 18-, 19-, and 21AWG.

However, many (including AQ) believe one is better off separating the different magnetic fields created by the low-pass and high-pass sections of the crossover by using physically different cables. IOW, they believe you're better off using 2 separate medium-price cables rather than one very expensive single cable no matter how many pairs of conductors it has.

I double biwire my 2- and 3-way speakers. (Virtually all 2-way speaker systems use a high crossover point; most 3-ways use a low crossover point.) The former combine bass and midrange in one section and hence benefit from the 'quality' and 'quantity' parts of the cable, while the tweeter-only section of a 2-way benefits from the very-highest-quality conductors while not needing much material for the low-current treble. Three-ways run bass on the bottom and combine midrange and treble on the top. The bass requires good (but not great) conductor quality but a lot of it. The MR/treble benefits from the very-highest-quality conductors but doesn't need quite the high-current capacity that the bass does.

On my 2-ways, I use AQ's KE-6, a 4-pairs-of-silver, DBS cable, on the bass/MR and KE-4, a 2-pairs-of-silver, DBS cable, on the treble. On my 3-way center, an Aerial CC3B, I use inexpensive Type 6 with 3 pairs on LGC copper on the bass, and KE-6 on the MR/treble.

All 3 of these front-channel speakers have never sounded better.
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Newbee: "Plamenz, Your amps would have to have the same input sensitivity to function properly."

Well, sort of. The input sensitivity has to be the same for the same power output. Some reviewers (but virtually no manufacturers) test and publish input sensitivity for 1-Watt output, and high-power amps tend to have less voltage gain. If one looks only at published sensitivities at rated outputs, 2 amps could be different but the same. They're different in that one is rated 0.5 volts in for 50 Watts out while the 2nd is rated 2 volts in for 200 Watts out. They're the same in that they both have the SAME voltage gain--which means they'll have the SAME output voltages--for the same input, until, of course, the 50-Watter runs out of power.

If the 25-Watter is a receiver, it has volume controls so it sort of doesn't matter what its input sensitivity is, simply adjust the volume to have the treble balance you want.

Personally, this sounds like an exercise in futility to me, as the 25W. amp probably won't SOUND any better than the 70W. amp, and you'll be introducing the impurities of another pair of interconnects to the treble, but it won't cost you anything.

Good luck.
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"I have a set of B&W CM4 speakers and a center CMC speaker. They all have 2 sets of terminals; my dealer did not explain anything to me about "bi-wiring," [SIC] he just said that "true audiophiles" (?!?) just use the lower terminals..."

Sounds to me as if your dealer wouldn't know a true audiophile if one walked in the door. It's a cinch the dealer isn't one.

"From what I have read here, though, it would appear that my speakers are set up for bi-wiring [SIC] - is this correct?"

Yes. One pair of terminals drives the lower-frequency part of the crossover*; the other drives the high-frequency part of the crossover.

"My receiver is not set up for bi-wiring [SIC]..."

Amplifiers never are; they don't have the crossovers networks in them.

"..., but I reckon I can just use one terminal for 2 cables.:

Yes, one terminal pair.

"And, could anyone clarify whether or not bi-wiring makes a sonic improvement? Newbee said he didn't feel there was a meaningful difference, while Bgrazman said he thought it could make a pretty big difference. I realize it all depends on ones own ears and system, but I am curious, and would like to know if its worth the expense to experiment with this."

OF COURSE it's worth experimenting with it...or so many of us believe. (Do remember, Oak, that opinions about sound, music, and audio are like as......; everybody's got one and most of them stink. :-) ) Read Audioquest's blurb about it, here http://www.audioquest.com/ . ENTER, Cable Theory, page 5/10. Remove the jumpers between the 2 input-terminal pairs when biwiring.

"Also, if you use two cables to each speaker instead of the special - and expensive - biwire cable, I assume that both cables have to be the same brand and type."

Not so and probably not the best way to do it. Using identical cables gets you only the benefits of separating the 2 magnetic fields. (Read the AQ blurb.) Using different conductor sizes and/or different materials can gain you other audible benefits...and cost you a lot of money, too, maybe... READ more of this subject before playing much with biwiring.

* A 2-way speaker combines bass and mid frequencies in one driver and crossover section, while the 3 octaves of treble are handled by the tweeter. A 3-way speaker divides the frequencies, GENERALLY, with the bottom 3-4 octaves going to the woofer (and this is the lower part of the crossover), 2-3 octaves to the midrange, and 3 octaves to the tweeter. Most biwirable 3-ways combine the latter 2 sections and drive them with one pair of terminals and drive the woofer with the other pair of terminals.
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"It is a definite advantage to split the signal at the amp end and it is a must to use the same brand cable. Sounds like AQ are talking out of the wrong hole here. For the same reason that you must use the same length you must use the same cable. There is no point matching lengths if the basic electrical properties are all different. The signal getting to the various bits of the crossover must be in-phase and this simply will not happen if the electrons take different routes."

Oh my; we're talking about the AUDIBLE differences of billionths of billionths of a second now? '...basic electrical properties are all different'? Hardly.

Audioquest has perhaps hundreds of years of combined experience on its staff of people who care very much about sound quality and how to optimize it thru cable. YOU suddenly are smarter than all of them? I doubt it.
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