(03-01-2019 16:45)Коллайдер писал(а): Какая должна быть длина кабеля для эффективного затухания в длинной линии? 
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WSR Reber: Do you think that bi-wiring offers an audible improvement that justifies the cost? Can your speakers be easily bi-wired?
Vandersteen: Bi-wiring is very interesting. We have been doing it now for twenty years. Our smallest model, the 1C is not bi-wired, and we’re often asked why is our littlest speaker not bi-wired. One of the main advantages of the bi-wiring is the separation of the magnetic fields in the wire. I’m talking about the expanding or collapsing magnetic fields that occur when an amplifier is trying to drive a wire connected to a very large, heavy duty woofer.
This results in a tremendous amount of current going to that woofer and because it is not a simple resistive load, it’s a reactive load, the back EMF can be very significant, and you have to remember expanding and collapsing magnetic fields is how transformers work, so it can be very significant if that field is crossing through the very same wire that is driving the subtle signals involved with the midrange and tweeter. The reason we don’t do it on a small two-way is because it’s a very light weight responsive 8-inch woofer. So when you are talking about small, little speakers, I think bi-wiring just makes it sound different.
It can’t really be justified from an engineering standpoint and the money it costs to do it would be better spent on higher quality components for the crossover or better drivers. On the other hand, when you have a full range speaker which has a large low frequency driver in it-you know a very heavy duty, long-throw eight, ten or twelve-inch or anything larger-then being able to separate the magnetic fields by the use of bi-wiring can be nearly as big a sonic improvement as bi-amping.
I sometimes wonder if in the early days, the tremendous improvement that we got when we bi-amped things, 60 to 70 percent of what we heard was caused by bi-wiring and had nothing really to do with using two amps.
Modern amplifiers today can handle 20Hz to 20kHz just fine, and a lot of the improvements that we hear when we bi-amp may be because we also bi-wired at the same time. It’s pretty common nowadays though to have these bi-wire schemes where you have the wires within one jacket. This of course doesn’t take advantage of the main value of bi-wiring, and therefore is not really bi-wiring, it is a sophisticated way to mono wire. I believe a few of the advantages of bi-wiring are still there, so it probably should be described as the ideal way to mono wire a bi-wired speaker. However, it is not true biwiring.
True bi-wiring can only be accomplished when the leads carrying the lows, vs. the leads carrying the mids and highs, are separated from one another about an inch or two so that those magnetic fields can’t couple their energy into the leads. You have to remember that a bi-wired system with the leads separated an inch or two reflects the impedance of the crossover all the way to the amplifier terminals.
So the transition of the cross over of the lows vs. the highs is actually occurring at those junctions at the amplifier terminals, because the wire attached to the midrange and tweeter will represent a very high impedance at let’s say 20Hz. That signal at 20Hz is going to take the path of least resistance, which at that point would be the wires that are hooked up to the woofer, because it represents a 4 ohm or an 8 ohm load. The wire that is hooked up to the midrange and tweeter at 20Hz is going to represent about 100 ohm load. This is how crossovers work by reflected impedance, so that is just like physically removing the crossover from the loudspeaker and putting it at the amplifier terminals. I think one of the reasons why there is so much controversy about bi-wiring is that there aren’t many who truly understand how it works. There are a lot of people doing it just because people are doing it.
