To Jeff Fritz,
A most interesting approach [“Comparisons on Paper: Bowers & Wilkins 802 Diamond D3 vs. Magico S5 Mk II”]. I am looking forward to reading “Part 2” of this theoretical comparison, which certainly will deal with parameters being most relevant for the audible performance -- especially when seeing that you selected two most different design concepts for this comparison.
Isn’t it most strange that both companies offer a totally different concept concerning the shape of the baffle? Another crucial point should be the concepts implemented for getting a coherent wave front from the four drivers at the intended (which distance?) listening spot. Are there any data from the manufacturers? What about the inherent drivers’ phase shifts due to the design of the crossover for these three-way topologies?
What about the appropriate amps for best matching? They should not differ from the amps the manufacturers used for voicing their speakers! And what about the best room size depending on the room modes that should differ due to the closed cabinet and bass-reflex design?
When evaluating speakers from such renowned companies I expect getting these data from the spec sheets!
Ah, the spec sheets. Yes, I have several wishes with regards to spec sheets. One would be that they are more complete, as you say. More data is better, and in the age of Internet shopping more and more buyers are relying on manufacturers’ published specifications to aid in their purchasing decisions. For this data to be useful, however, we would need for the specifications to be standardized in some way, so that the buyer is comparing apples to apples. I do not think that will ever happen, however.
Getting some of the other information you seek is not incumbent upon the manufacturer to provide. One would be room size for an intended speaker. It has been my experience that it is almost impossible to correlate available speaker specifications with appropriate room size. I do not think enough data is available, and even if it were, you would have to be able to interpret this data and convert it into a useful metric. You could make the case that low-frequency extension would be an exception, but I can’t tell you how many times I have seen large speakers work in medium-sized rooms and medium-sized speakers overload a largish room.
As for predicting wave launches and the ensuing phase shifts for a given speaker based on baffle size and shape, as well as crossover topologies, there is a far more reliable method to get this information than simple conjecture. Although a trained eye can easily spot areas where diffraction might occur due to hard edges and sharp corners on a baffle, you can view exactly what is going on when you look at the measurements we do at Canada’s National Research Council, in their anechoic chamber. It’s a shame we can’t measure every speaker we write about.
Ultimately, I agree with you -- the more information the better. Just don’t hold your breath for it. . . . Jeff Fritz