Eddie Runner

Nousaine wrote:

Actually you don't seem to understand that
a standing wave requires 2 opposing surfaces to form.

Tom, your forgetting your simple physics!

Dont you remember the high school physics books with one end of the string
tied to
the pole
to demonstrate standing waves?? That represents ONE reflector...!!!

Sure but the string was terminated at both ends now wasn't it. This is
acoustics Eddie.


Dont you remember the OPEN ENDED TUBE??

No I don't. It was closed at both ends where I went to school. Otherwise the
medium blowsl out of one end.


Do you know the DEFINITION of STANDING WAVE???

Obviously you don't with regard to acoustics.


Do you DOUBT the definition I gave earlier??

On the contrary, a standing wave CAN exist with only one reflector...
Please study on this matter a bit more Tom...!!

The effect you were trying to "draw" isn't a standing wave phenomenon. It's an
acoustic cancellation that occurs at 100-300 Hz or higher. The most common
example is the famous tower speaker floor-bounce notch. It's an wave
interference issue not a standing wave.

You dont need TWO walls or reflective surfaces!

If you don't, the wave won't 'stand'; it'll propagate into space.

You can do it with a SPEAKER and ONE WALL just like my example

OR you can do it with TWO SPEAKERS and no reflectors if you wish!

And of course you can have MORE than that as well...

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

You can keep on making it up but this won't make it true. The Allison effect is
real and occurs in real spaces BUT it happens at higher frequencies. The
cancellation notch in a single wall example at a distance of 3 feet occurs
around 150 Hz. At 1 foot it occurs at higher frequencies. So? It isn't a
standing wave.