wjm@whuxk.UUCP (06/10/83)
I agree with the past few articles about the need for high power amplifiers
if one wants to get "realistic" volume levels and accurately reproduce the
90 dB or so of dynamic range that one can get from audiophile analog and digital
recordings. Given that most speakers used for audiophile purposes produce
about 80-90 dB SPL at 1 meter for a 1 watt input, you need 100 watts to
obtain a 110 dB peak (which is reached with a symphony orchestra) if there
are no other losses due to room acoustics, and the speaker is at the high
end of the efficiency range. However, Mother Nature isn't nice since most
high end audiophile speakers that have been discussed on the net tend to
be at the lower end of the range. Thus, one should consider an amp with a
peak handling power of 1 KW or so (which would be a 500 w/ch RMS amp with 3 DB
of dynamic headroom, for example). Given the demands placed upon a stereo
system by the availability of good program material, I don't think an amp
with 200-500 w/ch of peak power is the least bit unreasonable. Given the
usual 2 to 3 dB of dynamic headroom, an amp with 120-250 w/ch of RMS power
seems appropriate.
Note to any of my neighbors who are reading the net ... Don't worry - these
volume levels are only hit on infrequent peaks during classical passages.
Most of the time for those of us who listen to classical music the amp is
loafing along at .5 w/ch or so, but it sounds a lot better to hear a CLEAN
peak than to have the amp clip. (Its also a lot kinder to one's speakers -
especially the tweeters with the high frequency content produced by a clip).
As far as something that drives me up the wall, very few things sound wors
than a TV set or cheap "stereo" with the volume control wide open. Although
a SPL meter would probably read lower than if it were used on my hi-fi system
the 10-25% THD or so from that el-cheapo 2.5 watt amp clipping sounds much
worse. (The only thing that's in its class is the BMT, and sometimes I'm
not sure about that.)
Bill Mitchell
Bell Labs - Whippany NJ
(whuxk!wjm)