To answer your questions, the general benefits of a 6db per octave crossover design are claimed to be first that, at the proper listening distance, the drivers blend better, seeming more like one, seamless driver. This is because the transition from one to the other happens more gently, with the drivers sharing the spectrum over a greater span. Also, as mentioned by Drubin, these 6db per octave slopes confer good phase integrity as measured by good step and impulse responses. The price to pay is that the drivers must be linear over a much larger passband than with higher order crossovers. Many drivers behave badly when hit with suffient energy at the top, or bottom of their intended ranges. Tweeters have trouble with the large excursions required for them to play loudly at lower frequencies. The large cones of mid-bass drivers often have audibly annoying resonances at the top of their range. As it is, with most two way speakers, the woofer is operating in controlled breakup at the top of its range. This actually is a trade-off that generates much greater dispersion in this area. The result is that most of these drivers are, in and of themselves, not really phase coherent when employed in this manner. The logical thing seems to be to add more drivers, each having less bandwidth to cover. New problems arise. Is it hard to make two drivers blend? Well then, try three, four or.... For a given price point as you add drivers you split your budget, and the quality of the driver. Some designers, and listeners like the sound of this trade-off and some do not as it is realized in specific speakers. I would ask you what models of speakers you have heard, and like with this topology? It does up the complexity of the task. That said, there are really excellent examples of speakers using all different types of crossovers. They coexist in the market because different listening biases, rooms and musical tastes can cause one to be favored over the other. Much of the magic also lies in the drivers (can't make a silk purse out of sows ear) and the cabinet. Good luck in your journey.
First Order Crossovers: Pros and Cons
I wonder if some folks might share their expertise on the question of crossover design. I'm coming around to the view that this is perhaps the most significant element of speaker design yet I really know very little about it and don't really understand the basic principles. Several of the speakers I have heard in my quest for full range floorstanders are "first order" designs. I have really enjoyed their sound but do not know if this is attributable primarily to the crossover design or to a combination of other factors as well. In addition, I have heard that, for example, because of the use of this crossover configuration on the Vandersteen 5 one has to sit at least 10 feet away from the speakers in order for the drivers to properly mesh. Is this really true and if so why? Another brand also in contention is the Fried Studio 7 which also uses a first order design. Same issue? Could someone share in laymans terms the basic principles of crossover design and indicate the advantages and disadvantages of each. Also, what designers are making intelligent choices in trying to work around the problems associated with crossover design? Thanks for your input.
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- 109 posts total
- 109 posts total