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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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gregm
3,409 posts
 
Cdc-- I only dimly remember the Jordan circuit, but it looked like a contour rather than BSC (it was across the driver -- but don't hold me on this!).

Skrivis:
Re: first order+ drivers. Why not use a wide-range drivers -- i.e. a 8" + supertweet, then a hefty subwoof. You'd have to biamp (at least) but, as you note, there's no free lunch!
skrivis
30 posts
 
Gregm> "Why not use a wide-range drivers -- i.e. a 8" + supertweet, then a hefty subwoof"

Well, an 8" driver is generally going to be getting pretty far away from a pure piston at treble frequencies.

Perhaps a smaller mid-woofer crossed at 3-4K to a tweeter, and then a woofer or sub below it, crossed at maybe 100 Hz?
cdc
1,828 posts
 
Thanks Skrivis and Gregm. I have tried twice to respond but both times, 15 minutes into my response my computer crashes from doing Ebay auction at the same time. So I give up.
gregm
3,409 posts
 
Cdc: forget the perfect piston. It'd be nice to have -- but let's just dream for now:)
An 8" driver has the advantage of being able to cope with mid & low-mid frequencies w/out extreme excursion. A smaller driver would be straining. OTOH, it WILL beam, as you hint, higher up. That'll narrow the sweet spot but, on the brighter side, IF the dispersion changes in a reasonably controlled manner, you reduce reflections... (at least that's s/thing). If the full-range can take it elegantly, I would try cutting in the tweet, 1st order, higher around 8kHz.
It's a pain to align the drivers -- but once it's done, it sounds good.
Cheers
cdc
1,828 posts
 
Greg, I like the concept. The equation I use is 1,100/ freq = wavelength (ft). So a 2" driver would start to beam at 8K. How do you align the drivers? If you use a 1" tweeter I would think you get a flare if you drop it in at under 13K.
My concept is to use a 4" Tang-Band or new WR125S from Creative Sounds. Both roll off over 10K so you use the natural rolloff of the driver and add a tweeter with a capacitor to cut frequency below 10K. I'm sure my inexperience is showing here but this is what I'd like to do. Minimal x-over and F-R to 20k. Beaming would be a minor issue.
On your 8K concept there is Hammer Dynamics 12" but I think the main driver has a whizzer which I am against using. Here are Other single drivers
Have fun. Let me know what you think.
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