Tom MacIntyre wrote in
news
On Mon, 01 May 2006 22:46:14 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
m:

On Mon, 01 May 2006 21:51:05 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
m:

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency
noise !!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because
our ears are more sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom


Probably. I wasn't thinking hard about that, I was just caught by
the claim that HF dominates white noise in the audio band, when
white noise is defined as being made up of all frequencies present
with equal energy in each.

Hmmm...equal energy means that it would be more energy per octave at
higher frequencies, right?

Tom


Yes, but that comes down to how you define the scale. The only reason,
following from that, to say that HF dominates in the audio band, is
because of expressing a log scale as lin, as pitch as opposed to
frequency. If you say that the pitch notation is purely based on
musical needs, and prefer the frequency scale for electronics
analysis, surely you also have to discard with it the notion of HF
dominance.

The reason the claim that HF dominates seems wrong to me, is I think a
peice of string is its own length, regardless of whether we measue in
inches or centimetres, let alone a nonlinear scale. White noise has a
very specific definition, in which energy is equal across the
spectrum, does not dominate part of it. It's out perception of pitch
that does that.


Interesting about the string, because we can simulate musical octaves
by folding a piece of string in half again and again.

Wouldn't a scale from, say, 100 Hz to 1600 Hz sound "interesting" if
we used 100 Hz as the semitone, rather than 2^(1/12) x f? :-)

Tom


That would form the first 15 overtones of a natural harmonic series based
on a fundamental of 100 Hz, and yes, it does sound cool. If you've got a
synthesizer with either microtuning scales, or a resonant filter, you could
set that up.