sound theory????

Q

QuickHand

Guest
Hi all
Where can find article on sound...like what is dezibel...or wave lenth? stuff like that...
any tips
thanks
QuickHand
 
ah, decibel and wavelength... that's physics my friend.
the physics of music. I'll try to tell you shortly about this stuff

decibel- the unit of volume of a sound. the system of decibels works in a system of powers of ten. For example. What is twice as loud in actuallity is hardly even distinguished to us. What DOES sound twice as loud is actually 10 TIMES as loud. There is an equation for this, which is:

B(beta) = 10(log(I/Io)

(the log is to base 10)

I is the intensity of the sound and Io is the intensity of the softest sound audible to the human ear, which is ... well I forget offhand what it is. but, it's something times ten to the -12th.
and I is defined by the equation:

I=P/(4(pi)r^2)

p is power, r is the distance from the source to where the sound is being heard

now wavelength is a long explanation. even longer than this. I'll explain later, because I have to leave for class soon.

later
-Mike

[Edited by dj funkifize on 02-16-2001 at 09:39 AM]
 
it is represented with the greek letter Lambda which looks like an upsidedown lowercase "y"

wavelength... in essence the length of the wave from crest to crest or from "node to node," or half of one period (T).

One period is actually the time it takes for one full oscillation. It would be better if I could draw it here to show you.
If you know what a sine wave looks like... a sideways "s"-- kinda like this ~. You see how there is a maximum, a minimum and 3 "null points" (where it's right in the middle of the max and min)? That's a representation of one period.

and one period is the time it takes for two wavelengths.

and I guess you've heard of "frequency" well frequency is just 1/(period) [f=1/T]. the number of oscillations in 1 second. So if a sound has a frequency of 440 Hz(hertz) that means it's vibrating 440 times per second. and it takes 1/440 seconds for one vibration.

well, that's the VERY basics of that. It's hard to explain without being able to show you. If you're really interrested, it's the part of physics known as accoustics. If you're in college, there's usually a course for the music majors called "accoustics and sound" or something like that, which youcan take. If you're out of college, try takiing it at your comminity college. And if you're younger, take high school physics. Or if you're younger still, ask your science teacher about it.
=)
-Mike


[Edited by dj funkifize on 02-16-2001 at 05:54 PM]
 
Hi all
Many thanks to you guys for the reply...you guys are great!
thanks again
QuickHand

mmmm...another question if don`t mind..I know I have once already posted on this topic but now got no real reply

How to build a sound mixer in flash, where user can record the sound and save...like this one http://www.onlinedj.com/onlinemixing/trancegalaxy/frameset.shtml


any tutorial or anbody wanna share the knowhow with me ..please

Thanks a lot for your help
;-)
 
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