penguin121
100+ Head-Fier
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- Jun 20, 2009
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Quote:
For the 1 mm (±0.5 mm) excursion of a 1 kHz sine wave, the maximum speed is 3.14 m/s. If you know the displacement amplitude (X = 0.5 mm) and the frequency (f = 1000 Hz) of then you can calculate the velocity amplitude (V), which is V = X*2*pi*f. Similarly, acceleration amplitude (A) is A = X*(2*pi*f)^2. I'm not sure what a more reasonable excursion for listening levels at this frequency would be, but whatever it is, the corresponding peak velocity with be reduced by the same factor. So back to the original question, the drivers aren't going anywhere near the speed of sound.
Originally Posted by JaZZ /img/forum/go_quote.gif A membrane vibrating with 1 kHz and an excursion of 1 mm (±0.5 mm) has an average speed of 1000 x 2 mm = 2 m/s (triangle waves). I can't calculate the sinc function, but the estimated maximum speed of a 1 kHz sine wave will be about 4 m/s (= 14.4 km/h) at the zero crossings in this case. But note that an excursion of ±0.5 mm at 1 kHz means a rather extreme volume level for a headphone driver. . |
For the 1 mm (±0.5 mm) excursion of a 1 kHz sine wave, the maximum speed is 3.14 m/s. If you know the displacement amplitude (X = 0.5 mm) and the frequency (f = 1000 Hz) of then you can calculate the velocity amplitude (V), which is V = X*2*pi*f. Similarly, acceleration amplitude (A) is A = X*(2*pi*f)^2. I'm not sure what a more reasonable excursion for listening levels at this frequency would be, but whatever it is, the corresponding peak velocity with be reduced by the same factor. So back to the original question, the drivers aren't going anywhere near the speed of sound.