acorec said:
Well.........A speaker has a voicecoil that drives the cone. The center has a short throw (called "speaker excursion). The outside of the speaker (the edge) has a longer excursion. So, the center will have much of the treble sound while the edge will have the low end "punch"
It's true that the high frequencies radiate predominantly from the center of the speaker, but the statement above really isn't the right way to describe it.
A guitar speaker has two things working against it with respect to high frequency reproduction - the diameter and mass of the cone. Large diameter cones force the high frequencies to "beam" into a very narrow angle. I won't go into the details, but it has to do with the sound waves from each part of the cone constructively interfering out front, but destructively interfering off to the sides. A massive cone is simply very difficult to move at high frequencies. The way speaker designers try to get around these limitations is by making the cone flexible along its radius in a controlled a manner. This is done by varying the thickness of the paper, or more commonly, adding circular corrugations.
The idea is to make the cone move as one single unit at low frequencies, but only have the center move at higher frequencies. The corrugations and damping properties of the paper attenuate the high frequencies as they travel radially outward from the voicecoil and through the cone material. This effectively lowers the mass and size of the cone at high frequencies, yielding wider and higher frequency response. Of course, the wider dispersion thing doesn't work terribly well, as any audience member who has the misfortune of sitting directly in front of a guitar cabinet knows!
So the center of the speaker actually has a
longer excursion, because it's reproducing both the low and the high frequencies.
Thomas
--------------------------------------------------
Barefoot Sound
Recording Monitors
