Question on Linkwitz 521.4 Speaker Crossover Design

[rb132333]

I struggle with crossovers and I believe I am not alone. I constructed only a few passive and I would be completely lost without tools such as PCD (Thanks Jeff B!). I was re-reviewing Linkwitz 521.4 (God rest his soul) and I see that the bass is crossed over to low-mid (7") at 120 hz; the low-mid to mid (4") at 1K hz and the mid to tweeter at 7k hz. Based on my research about crossover design, a few general rules of thumb have been broken - 1) keep a single driver to 3 octaves or less and 2) crossover a driver before it begins beams. The mid in 521.4 breaks both of these rules, yet many listeners have given this speaker high ratings. Can some of the experts weigh in and explain why Linkwitz took this approach and why it seems to work well for him?

 

[chrisb]

I’d venture to posit that the 521 breaks a few other “conventional rules” as well - or perhaps it’s better said define a new territory of marriage of acoustic and band-bass filter design not frequently gifted to the DIY comminuty. Judging from the positive reviews of those who’ve heard - or built them, I’d be inclined not to second guess them.

If you’re not already familiar, there’s a pretty healthy forum dedicated specifically to Siegfried’s designs. Could be helpful/informative to attempt to digest as much of the technical writings on the Linkwitz site, as well as to visit the OPLUG fora.
ORION/PLUTO/LX... Users Group • Index page

 

[Juhazi]

Well, it is a dipole multiway and each driver plays only in it's comfort zone. Nice dipole radiation pattern up to lowpass and not too much eq and distortion near high pass. No easy way there!

 

[Draki]

What they said.

One factual correction: the lowmid driver is in fact an 8-inch unit, not 7.

You could do worse that reading about its' spiritual twin, the NaO Note IIRS by John K.

Link: NaO Note II RS Details