Nousaine wrote:

Standing waves in the car
are shifted upward to roughly 60-600 Hz. In a living room they occur typically
between about 30-300 Hz.

I use a 50Hz tone in a car and I DO HAVE standing waves.. if there were none
the sound pressure would be EQUAL everyplace in the car!

Using a 50Hz tone there is NO WAY my frequencies are SHIFTED UP!
Unless I tune my oscillator up... Is that what you want me to do???

DUH

Eddie RUnner






but that is NOT needed to make a simple standing wave...

Find a definition of STANDING WAVE I thinkyou will find yourself WRONG!

There's a nice picture of a Kundt tube on page 2 of Everest's "The Master
Handbook of Acoustics" that describes how standing waves are formed with a
sound source at one end and a plug in the other end of the tube. You ought to
read this.


Standing waves are the result of interg\ferance. When two sets of waves
of
eaqual ampitude and wavelength pass through each other in opposite
directions
the waves are steadily in and out of phase with each other....

Ok how do they manage to travel in different directions unless there are two
sources? In your example, they are traveling in the same direction when they
interfere. That's not a standing wave.


this definition was from CONCEPTIAL PHYSICS seventh edition by Paul
Gittewitt.

Its one simple definition...

There is a MORE COMPLEX 2 wall and even a 6 wall defintion in the Sams
Handbook for Sound Engineers, but since Im not neccisarilly talking
about
more than one wall in my example (to keep it simple for the folks),

You have to keepit simple because it's quite clear you don't understand the
acoustics here. Your pictures describe an interference effect that occurs at
higher frequencies.

I
will
not use those definitions here unless I dcide to talk about more than
one wall..

Eddie Runner
http://www.installer.com/tech/

You don't get standing waves in rooms and cars without opposing surfaces.