This has a definite impact on the cabinet style of small monitors, since achieving an optimal radius would require a much larger cabinet. I'm glad this is true, because aesthetically I prefer hard edges to rounded. To me a cabinet with very sharp edges requires greater cabinetry skill, and represents a a more furniture-like quality of appearance.
Hey Jerry,
Since I am starting the path of learning about speaker design, with the goal of producing speakers for sale, I have spent a fair bit of time learning about edge diffraction and baffle step response. Here's what I've learned so far...
Edge diffraction and baffle step are very similar. Essentially they are both consequences of the following physical phenomemon:
1. Bass waves are non-directional in closed rooms, because the wavelength is very large compared to the size of the room, and compared to the size of the speaker. A 20hz wave has a wavelength of 56 feet, and a 100Hz wave is 11 feet.
2. High frequencies are very directional, and very short compared to the size of the speaker. 5kHz is about 2 inches long.
3. The above differences mean that high frequencies are radiated in only 180 degrees, while bass waves radiate in 360 degrees. This means that highs are "reinforced" by the presence of a wall behind the driver. This "wall" is the cabinet baffle.
The reinforcement is called "baffle step response", and is a real headache for speaker designers. It essentially causes a 6dB rise of the highs over the lows at some point in the audio spectrum, which needs to be compensated.
But where does the edge shape come into this discussion???
Well, the highs are reinforced by the baffle as if it were an infinite plane, except that eventually those frequencies will encounter the edge, where they diffract. Here is where the edge shape is critical. A sharp edge will cause all kinds of weird diffractions, which will mess with the sound in odd ways by creating many jagged harmonics. A smooth shape will cause many less diffractions, and in fact a perfect sphere will have a very smooth transition into the "stepped" frequencies. Our ears will tend to ignore smooth transitions, while sharp ones will be quite apparent.
Regarding cabinetry skill, it is the simplest thing in the world to make sharp edges. All you need to do is cut sheets of wood with a table saw, join the edges, and sand the joins smooth. Making curves is much harder, especially large, complex radius curves. That is where skill comes into play. The curves also have a much better effect on the sound quality, because there are not a lot of "sharp" edge diffraction and baffle steps mixed into the music.
So from a designer's perspective, curved cabinets equate to more skill, because they are better for sound quality.
