MOTM

In a message dated 1/6/2001 7:26:25 PM, jlarryh@... writes:

>AM
>broadcast radio frequencies are in the hundreds of feet.  

Yeah, but radio waves travel a bit faster than sound waves (now who's the 
Stooge!).

>So, audio would
>be
>MANY times that.

Just off the top of my head I think the speed of sound (at room temp and near 
sea level) would be about 750 mph. And 750 mph = about 1100 fps (given 
750/3600 = 0.208 mps and 0.208 * 5280 = 1100 fps). So a 1 Hz "tone" would 
have a wavelength of 1100 feet and a 2 Hz "tone" would have length of 550 
feet. So a 20 Hz tone would have a wavelength of about 55 feet and a 30 Hz 
tone (only half way up the first octave of good human hearing) would be about 
36.7 feet. 

Now a "fun" experiment:
Put a 1.1 KHz sine wave through your stereo monitoring system (or stereo for 
that matter) which will have a wavelength of about one foot. It needs to be a 
bit loud (I mean not quiet). Now, slowly walk around the room (or slowly move 
your head around) and you'll hear the peaks and troughs of the sound pressure 
waves.

So Wavelength = velocity of sound (in the given medium)/ frequency

JB