[vox-tech] Linux sound recording

Mark K. Kim vox-tech@lists.lugod.org
Tue, 17 Jun 2003 11:05:05 -0700 (PDT)


On Tue, 17 Jun 2003, Peter Jay Salzman wrote:

> decibels are on a logarithmic scale, meaning they're non-linear.   you
> would think that 3 dB is three times as loud as 1 dB, but it's actually
> ten times as loud.

As others pointed out,

   dB = 20 log(x)

(log is base 10) so actually 3dB is about 26% "louder" than 1dB.

The human hearing is also logorithmic (as you point out), so if I
understand this correctly (it's entirely possible I don't), 3dB should be
3 times as loud as 1dB to the human hearing.

> of course, to a physicist, decibels are inconvenient, because to us,
> everything has a power of "P".    ;-)

Maybe I've mentioned this before, but... My physics teacher is high school
(who was also my electronics teacher) would always write "P" using a
yellow chalk.  Like when he wrote "p = i*v" (power = current * voltage) on
the black board, he's write the entire equation using the white chalk but
"p" would be written using a yellow chalk.  And in every single class,
without an exception, someone would ask him why he writes "p" in yellow.
And all our teacher would say is, "because it's 'P'.  'P' is yellow." :P

-Mark

-- 
Mark K. Kim
http://www.cbreak.org/
PGP key available upon request.