AQ的教材--关于双线分音
http://www.soundcity.com/info/faqsbiwiring.html
What is Biwiring?
Bi-wire by Audioquest!!!
This article is to help consumers to increase their understanding of BiWiring and clarify some misunderstandings. Many of today's speakers can be BiWired meaning the speaker has inputs for the woofer and separate inputs for the upper frequency ranges. Should you BiWire? If so, should you biwire with a single cable (Single BiWire / SBW) or with two separate cables (Double-BiWire / DBW)? Read on.
The whole idea of BiWiring often leads to the question "is BiWiring so important that I should spend twice as much on cable?" Maybe it is worth spending twice as much on cable in general, but that's a separate question. BiWiring is a way to save money or to get higher performance for the same price. The BiWiring question is not about how much money to spend, but about how to get the most performance for one's money. BiWiring is a way of providing your customers more value for the amount of money they spend.
When using a single speaker cable (not BiWiring) the large amounts of bass energy have an adverse effect on the upper frequencies. BiWiring is done in order to substantially reduce the distortion caused by speaker cable. In a BiWire set-up the cable feeding the higher ranges no longer handles the large magnetic fields caused by the high current needed to produce bass. BiWiring does not affect the bass fundamentals, but the treble signal now travels a less distorted path. A little like the difference between swimming through waves versus through smooth water. The bass will sound better because bass definition (harmonics) is in the midrange and higher frequencies. It is worthwhile to take advantage of the benefits of BiWiring when the speaker manufacturer has gone to the extra expense of providing this capability. The performance benefits of reducing distortion this way are substantial.
When BiWiring, the two cables must either be identical, or have essentially identical geometries. If the cables have different geometries they will have different inductance and capacitance. Capacitance and inductance are the values used to create a loudspeaker’s low-pass and high-pass networks (together making a crossover). Different values in the two cables effectively redesigns the crossover … not a good thing! The integrity and coherence of the speaker will be compromised.
For best performance, use two of the same cables. If the speaker has a low crossover point (a 3-way speaker or a panel-hybrid such as Martin Logan) much of the benefit of using two identical cables can be realized by using two cables which have the same geometry, but which use different qualities of metal. CV-4 paired with Type-4 to drive the bass, for example. Why do this? Price: It’s less expensive.
This “trick” does not work for 2-way speakers. They have their BiWire access frequency above the midrange … music and voice and practically everything else is in the midrange and must be given full respect. Use two identical cables.
Another option is using a single cable that can be divided to BiWire with. We call this Single-BiWire (SBW). This works better with some cables than with others – but BiWiring using two separate cables is always better. We do not recommend you Single-BiWiwire with a Quad-Helix model (Type-2, Type-4, CV-4, KE-4). If you are curious, make up two sets of cables and listen for yourself. Even more importantly, please understand that, except for the Flat-Rock Series, it is better to use two less expensive cables than to Single-BiWire with one better cable. Using two pairs of CV-6 is better than a Single-BiWired Mont Blanc, for example.
The Flat-Rock Series (Slate, Bedrock, Rockefeller, Gibraltar) are excellent for Single-BiWiring. While optimized for use as full-range cables, these models, when used as Single-BiWire cables, actually become a specialized true Double-BiWire thanks to their two Quad-Helix component. The two groups of conductors have a degree of magnetic autonomy found in no other single cable. Pretty cool, don’t you think?
Just as the Flat-Rock Series is excellent for Single-BiWiring, the Earth-Feature Series (Pikes Peak to Everest), is the poorest for SBW. One of the significant advantages of these cables is the unusually effective way they manage the relationships between magnetic fields. The conductors spiral in opposite directions, but the positive and negative groups form two tubes whose relationship is constant and non-changing. Dividing the conductors in these models does very little to separate the magnetic fields of the bass and treble groups.
That leaves the 6-Series in which Single-BiWiring is effective, though only half as effective as running a Double-BiWire of CV-4.
One can Double-BiWire by stacking connectors at the amp, or by simply ordering Double-BiWire cables. We simply join the two cables together at the amp end before attaching the terminations. The price is simply the same as adding together the price of the two cables, whether the same model or different models.
You, as the expert, are in the best position to evaluate your customer’s needs. 1) You may choose to sell the customer (for example) a Single-BiWire Pikes Peak because Single-BiWire is what the customer demands. 2) Or you may recommend two pairs of CV-6 because that is what will sound best. 3) Or you may recommend a single Full-Range pair of Pikes Peak and a set of AudioQuest PSC Jumpers to replace the disgusting sounding gold over nickel plated brass (or worse) pieces supplied with the speakers … this is the best way to leave open the possibility of adding another pair of Pikes Peak later, or better yet, a set of Mont Blanc or Kilimanjaro on the treble if the speaker is a 3-way.
When using a single set of cables to a BiWirable speaker, you might as well do it properly … it costs nothing and makes a difference you can hear. When using jumpers (factory supplied or replacements), be sure to put both red and black connectors to the treble input of a 3-way or panel-hybrid. Bass is less sensitive to having the jumpers in the signal path.
For 2-way speakers, be sure to put red to treble and black to bass … this is the only way to preserve the tonal voice the speaker designer intended.
If you do not BiWire, at the very least, please connect a single set of speaker cables as recommended above, and then if you’re not comfortable enough in the role of the expert to sell a $20 set of AQ PSC Jumpers, then use a small piece of solid conductor, or a cable like AQ Type 1, to do the jumping. Just as better electronics do not come with poor interconnect cables, it is best to pretend your fine speakers simply did not come with cheap stamped metal jumpers. It’s entirely accurate to describe the free shiny metal jumpers as “worth every penny you paid for them.”
