[TenTec] Re: 2 minor comments: Speakers and Centurion

[Rob Atkinson, K5UJ]

Hi Todd;

The foam is speaker enclosure baffling material.  It's used to lengthen the 
space the sound has to travel through without increasing the size of the 
cabinet.   This is a method used in cabinet design and is often found in 
stereo speakers.  Baffling flattens the frequency response of the unit and 
boosts the bass response slightly.  If you have an old speaker in a cabinet 
you can try buying some foam rubber at a hobby/crafts shop, cutting it to 
fit across the inside of the cabinet and put it in behind the speaker and 
hear the difference.  Large bass speakers with cones that move a lot will 
need an air tube exiting from behind the speaker either through the baffling 
or through the front to equalize the cabinet air pressure when the cone 
moves suddenly.  I doubt if this kind of speaker is used in ham radio 
however.

73,

Rob
K5UJ

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