Hi all,
> From: Ken Norton <ken@xxxxxxxxxxx>
> I used to be able to hear a quartz watch operate. There is a very faint
> whine to it.
Most quartz clocks use a 32.768 kHz crystal -- the first division of that
frequency gives 16.384 kHz, which is within the audible range... of some!
> CRT televisions still drive me bonkers, though.
That's 15.625 Hz (or 15.750 in USA, Japan etc), even easier to hear.
> When I was a
> child I had two nasty ear infections which caused about a 30% hearing loss.
Sorry to hear (pun NOT intended) about that.
Fortunately, it was a wide-band loss and didn't affect my frequency range.
> Until five years ago I could still hear 22kHz. Right now, it's down to
> about 18kHz, but I have to crank the levels up a bit more to hear it.
My headphone abuse at youth made me a big damage... I can't hear anything
from 13 kHz or so, but at least my hearing hasn't impaired since I was 26-27
-- and I still have *a lot* to hear in the previous 12 kHz ;-)
Fernando wrote:
> > Why 250 - 300 W/Ch? Amps able to deliver such an amount of power are
> better
> > constructed, therefore they distort less and have an amazing dynamic
> > range.
Not necessarily -- maybe most makers reserve the best components and
manufacturing for their flagship, most powerful levels... but in fact,
unless very exotic references are used, lower powered components do have
somewhat better specs.
Unlike a tube amplifier which will have
> a continously smooth level of compression, solid-state amps tend to be a
> little more harsh about it.
>
Yes, you are right. Depending on circuit design, it may sound even "nicer"
when distorting-clipping a bit -- the 'euphonic distortion. And it's sort of
addictive!
> 300 watts per channel is not really all that much for a home system.
Seems overkill to me, though. In fact, I'm about to finish the design (and
hope to build soon!) of a tube integrated amplifier -- single ended
6BQ6/EL84 driven by soviet-made 6N2P-EV (a much improved 12AX7/ECC83). I
don't expect it to give more than 2 W/channel, but will suffice for the
Wharfedale 8.1 in my bedroom.
This may seem a rather anaemic output, but have into account some facts:
-The ear's response is not linear, but rather logartihmic: to hear something
twice as loud, twice the power won't do; you need TEN times the power!
-Volume potentiometers usually render a 'logarithmic' behaviour, which may
or may not follow accurately the ear's response.
-I have measured the _average_ power while listening to music at a
not-wall-breaking-but-higher-than-usual-loudness: it was 0.1 W (!). Also,
during a test with a continuous 1 W RMS, we had to get out the room!
However, there may be a real need for a much powerful system: although the
_average_ output will be that low, then there are ocassional _peaks_ of
hundreds of times the average power. And that's why "tube watts" seem louder
than "solid state watts" -- because those peaks from an underpowered amp
would be clipped in a soft, sweet way and won't make any unpleasant
distortion, just would sound more compressed.
> I can barely tolerate MP3 recordings of ANY compression level.
It depends on the type of sounds, also. I'm not a fan of MP3, either, but
for non-critical uses, a mildly compressed file (say, 256 kbps or more)
_could_ be acceptable.
BTW, last Xmas we made an Audiophile Show at my school, gathering gear from
me (Dual 704 turntable, Shure V15V-MR cartridge) and my boss (AmpTek tube
amp, ProJect RIAA preamp, home-brewed speakers). It went well, although it
was difficult to resist the competition from the "churros con chocolate"
being served the room next ;-) Some pics of the event:
<http://cjss.sytes.net/post/audio/>
(mandatory Oly content: taken with a mju-2, slides scanned and processed in
a quick-and-dirty way)
Sorry, Moose: just a plain directory of files, no fancy navigation pages
here ;-)
Well, as you can see in some pics, I recorded the whole session in MiniDisc.
While this has a compressed format (near 300 kbps), the ATRAC seems a better
algorithm than MP3, without the cymbal-swirling. However, its Achiles' Heel
showed up with 10cc's "I'm not in love"...
Cheers,
--
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
--
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