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Extended harmonics - look at Self

Hi,

With all that feedback, I was curious what my weighted
THD measure would produce using D. Self's distortion results.

This weighted THD measure is based on:

sqrt( W2*W2*N2*N2 + W3*W3*N3*N3 + ...)

where the weighting values are given in the link below.
(Additional weights for the harmonics 13-26 are
in the spreadsheet.)

I extended harmonics out to the 26th because I think his
amp will extend harmonics (albeit) at a low level way out
into the audio spectrum.

For his THD value I used a number I got from a graph in
the March 2002 audioXpress article on page 29. I used:

.0015% which is based on a normal THD calculation of:

sqrt(N2*N2 + N3*N3 + ...)

all 26 harmonics were of equal strength at a value of 0.000003 or
-110.5 db below the fundamental.

I then calculated my weighted THD measure. The value I got for this
was .021%. This is 14 times bigger.

Its interesting, because had the harmonics been extended out to
say 32 or even further, the weighted THD number would have gotten
even bigger.

There could be more going on beyond -100db then first appears.


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  • Extended harmonics - look at Self - mfc 05/19/0300:59:11 05/19/03 (0)
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