Author Topic: dB decrease over diatance  (Read 3728 times)

a.j

  • Guest
dB decrease over diatance
« on: October 11, 2003, 04:20:37 AM »
How does a dB reading measure in theory as distance increases?



eg:



1m (meter) 90dB

2m = ?

4m = ?  

8m = ?

64m = ?



is it frequency dependant as well?



I am thinking of lower frequencies, and  I thought I read on line  that it reduces spl by 6dB for every doubling of distance.



If so, that scenerio above would be:



start at 90dB at 1m

2m = 84dB

4m = 78dB

8m = 72dB

16m=66dB

32m=60dB

64m=54dB



and is it true that the threshold for lower bass is in this 50dB range?



lets get some replies...

aj

Kira

  • Guest
Re: dB decrease over diatance
« Reply #1 on: April 26, 2005, 12:59:29 AM »
I don't know about the sound diminishing over distance but my nearest neighbors live about 75 yards away and they say that they can hear the bass from my house loud enough to interfere with their tv sound. I do know that lower frequencies take longer to reach a peak. Picture a choppy ocean-that is like higher freqs. Now picture a gently rolling ocean; that would be how bass frequencies travel, it is farther between sound peaks. (that's the way it was taught to me anyway! :)

supersoundproofing

  • Guest
Re: dB decrease over diatance
« Reply #2 on: May 10, 2005, 12:38:52 AM »
Generally, sound loses energy to the square of the distance.  

This is usually enough for practical considerations.

We don't like to get real technical on the site, because one can get bogged down in math and statistics.

If you are into that, check into the newsgroup at
sci.physics,alt.sci.physics.acoustics
a very interesting bulletin board like this, but with professors and technical folks- some who are not too freindly with neophytes!

 

anything