When I see spins like these in modern day speakers relative to the best of the best in the 70's, 80's and even 90's, it does make me want to use the term "mops the floor".
View attachment 533369View attachment 533370View attachment 533371View attachment 533373
The effectiveness of spins varies with rooms--some rooms need the smooth directivity that a spin shows more desperately than others.
And Floyd Toole was measuring directivity in the Canadian National Research Council anechoic chamber started decades before working for Harman, and he certainly taught them how to make measurements of directivity part of the design process for several of their brands (particularly including Revel).
The NFS is a way to get anechoic measurements without the anechoic chamber. I would say that an anechoic chamber is the gold standard for speaker frequency response and directivity measurements, subject to: 1.) staying above the anechoic threshold frequency, and 2.) taking the measurements from the appropriate locations.
What the NFS does is to apply rather advanced calculations to measure and then filter out the effects of the room in which the scanner sits, so as to eliminate the effects of reflections. The MLSSA was an earlier way to attempt this. The NFS system is quite expensive, but it's cheaper than a proper anechoic chamber.
What the designer does with the anechoic measurements is a whole other question.
The need for smooth directivity based on multipoint measurement emerged when? 80's? By the 90's, there were example products incorporating the principle, and it had already been incorporated to various extents prior to that time with less clear ways to measure it. The concepts were clarified greatly by Floyd, but they were understood at least on an intuitive level by others.
McIntosh built its anechoic chamber (a big one) in the middle 70's. Prior to that time, they used different approaches, even including tools like the opposite of an anechoic chamber--the reverberant room. But they didn't use it for measuring directivity, or at least not with the same level of understanding we have gained from Floyd's work on directivity.
Floyd has told us that a good speaker has a first priority, which is flat frequency response on axis. The second priority is eliminating audible resonances. Having great directivity doesn't help if those first two priorities are not achieved (but the flat frequency response is possible using equalization).
I think there has been quite a lot of advancement in the use of, say, subwoofers to address room resonances below the Schroeder frequency where equalization is less effective. I see that as application more than design, though.
I think my 20-year-old Revel F12's stand up to the current Concerta towers quite well, and where there has been a measurable improvement has been solving the distortion problem at the crossover point (the F12 has a distortion peak at about 1.2 KHz that later models do not have). But the new ones don't extend into the bass as well at as high a listening level. Clearly Revel understood the importance of good directivity back then and before then--the all-important wave guide surrounding the tweeter is much more like current models than it is like anything made in the early 90's or earlier. (They also understood dynamics, which I think is remarkable at the original price point of the Concerta models.) (And I should add that PA speaker designers sure understood directivity, but perhaps for difference reasons--horn designs varied from long-throw exponential horns to short-throw bi-radial horns. An effects like diffraction and so on were certainly on the minds of designers of old.)
Rick "the F12's were $1600 a pair when new" Denney
www.stereophile.com
). It's very hard for me to believe that there have been no improvements since then. And indeed the spinorama above 600Hz is, well, just not very good by modern standards, in either smoothness or directivity.
. It also placed the soundstage at the same height as the projection screen. I would do it again. The height of the tweeter is less important than the reference axis, which can be tilted electronically. The transducer count allowed the system to play as loud as I could stand and still sound good.
, although that was not my reason.
