Arny Krueger wrote:
wrote
I think I've decided on buying a pair of Infinity Beta 50
speakers.
I'm among two receivers--a Yamaha 497 (75w per ch) and an
Onkyo TX 8522 (100w per ch).
One salient difference is that the Yamaha claims a 0.04
THD, and the Onkyo a 0.08.
Not relevant. Besides what Richard said about the speakers having tons more
distortion, THD measurements like this can be fudged for marketing purposes,
while being perfectly honest.
A well made SS power amp usually has about 0.03% or less THD at all levels
up to maybe 3/4 of the power level at which the amp clips.
THD specs are typically made 'just prior to clipping'.
The THD in the 100mW to 1W region will be significantly higher than the 'data
sheet figure' though for all typical Class AB bipolar output stages. This is why
amps that only make say 0.08% on the spec sheet ARE audibly inferior to their
betters.
My own benchmark of suitability for good quality audio is a 'spec sheet' figure
of 0.01% which is likely to translate to ~ 0.1% at lower wattages.
Look at this (page 9 "THD + N vs Output Power") for an example of what I mean.
http://www.national.com/ds.cgi/LM/LM3875.pdf
The LM3875 was popularly adopted as the 'Gainclone' in some circles some years
back.
Graham