http://www.mcsquared.com/wavelength.htm

 

its not acurat but thanks 30 hz shald be about 3 meters the calculater said 11. somthing corect me if im wrong

 

Speed of sound at sea level is 340.29 m/s, so

340.29 / 20 = 17.01 m
340.29 / 30 = 11.34 m

(calculator says 17.2, 11.47 - so I guess their speed of sound is slightly different)

Maybe you're thinking of quarter wavelength?

 

(calculator says 17.2, 11.47 - so I guess their speed of sound is slightly different)

Yup. Varies with air pressure and temperature.

 

I understand the physics behind measuring the distance of one wavelength, I've just never heard a good explanation of why I should care. The driver moves in and out compressing and rareifying the air in front of it. What difference does it make how far the first pressure peak is from the driver when the next peak occurs? Thanks for the answer that will open my eyes to the wonders of acoustic phenomenon.

 

Sound energy is divided into frequencies. Each frequency has a given size or length. The speed of sound, 1130 ft./sec., stays constant and is used to calculate the length of a particular frequency. To find the length of a given frequency, we take the speed of sound, 1130 ft./sec. and divide it by the specific frequency we want to find the length of. If we use 20 Hz. as our frequency, we take the speed of sound 1130 ft./sec. and divide it by 20. Our answer is 56.5 ft.