Question about wavelengths

[Vega 10+ year member]

I was on bcae and I was looking at wavelengths so I have a question. Say a 40hz tone takes 28 feets to make the full wavelength so would the frequency be louder 28 feet away where it makes the full wavelength or closer?

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[SSS 18734 5,000+ posts]

Sound travels in the form of a longitudinal wave, not the conventional transerse wave that is depicted on the computer screen. So just because it completes a full cycle at 28 feet doesn't mean it will be any louder at that exact distance. the intensity of the sound, given that it is in a wide open area, will diminish as distance increases.

Take a look at this site to illustrate the difference between longitudinal and transverse waves.

http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html

 

[Pyro_By_Nature 5,000+ posts]

Not really.The wonderful thing about bass, is the wave does not need to fully develop to have maximum output.Sound actually loses energy the farther it travels.

 

[hoss 5,000+ posts]

anyone wanna bring up the 1/4 wave theory to illustrate how little of the wave needs to develop in order to give full output //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Vega 10+ year member]

anyone wanna bring up the 1/4 wave theory to illustrate how little of the wave needs to develop in order to give full output //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Where can I find out more about this 1/4 wave theory?

 

[hoss 5,000+ posts]

the basics of the 1/4 wave theory is that only one fourth of the wave needs to develop in order to achieve maximun output. and alot of SPL competitors use (or used it, dont know how many still are) it to determine their tuning/and frequency that will be loudest in their install.

the closest you could get to exactly 1/4 of a wavelength developing would give you the best output. and im not completely sure of everything about it, so take this whole explanation with a grain of salt //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif , but iirc you measure the distance from the cones of your subs, to the mic placement, or head rest if you want the loudest to the ears, then you figure whatever frequency yields a wavelength four times that distance, and thats what you tune to for maximum output //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

again, thats my understanding of what it is, im sure someone can come behind me and correct me //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif