wjm@whuxk.UUCP (06/30/83)
While the "nominal" high end of human hearing is 20KHz, this is only one of
those biology or med school textbook "normal" things. There are some individuals
in the population (most of whom are < 40 years of age and who havn't abused their
ears by working in high dB environments or listened to disco music at disco
volume levels) who can perceive sounds at or above 20 KHz. I personally am
blessed and/or cursed with this situation - blessed since I can enjoy the high
end on my stereo system and the top octave of music - e.g. the bells in the
'1812 Overture' and harp music - but cursed since ultrasonic anti-shoplifting
alarms operating at 25KHz drive me to the Excederin or Tylenol bottles!
Therefore, I contend that flat response to 20KHz should be a design objective
of high fidelity audio equipment. Admittedly, when one is designing to a
more moderate price, one may have to compromise here (as in many places) but
one should not design a digital system, for example, with a sampling rate of
less than 40 KHz (the minimum rate needed to reconstruct a 20KHz signal from
sampling theory).
Also to re-open an ongoing controversy, this is the reason that I stand by
my contention that the Shure V15 Type V is not a top of the line cartridge
and why I would pay 2x the $$ to purchase certain other MC cartridges.
According to the lab test reports in last summer's issues of "Stereo Review"
and "High Fidelity" (I'll provide page and specific issues on request, if
anyone can't find them) the V15-V has two serious flaws in the top octave.
1. Its frequency response is rather non-flat around 16KHz
2. Its stereo separation is < 10 dB at 20KHz. Given that the high frequencies
are the most directional, I regard this as a significant problem.
Don't get me wrong - the V15-V is a fine cartridge for its $125 price, and I've
recommended it to some of my friends for use in a $1K to $1.5K system.
However, lets not kid ourselves, it isn't in the same class as the following
$250-300 MC units - the Adcom XC-LT (my present cartridge), the Dynavector
23R, or the Denon 103D (two units I'm considering to replace the Adcom which
is showing its age - another Adcom is also on the list)
I'm not necessarily partial to a particular transducer technology. Like mayny
engineers, all I care about is the quality of reproduction. However, the only
cartridges that I've heard so far (when price is no object, of course) that
challenge the state of the art are MC's. If someone can design a MM that falls
in this class, and that is verified by independent lab tests, I'll be the
first to acknowledge it - and be happy not to use a head amp.
but until then I'll just have to stick to MC's.
End of flame .... Bill Mitchell
Bell Laboratories - Whippany
(whuxk!wjm)
Disclaimer ... of course, all opinions submitted by yours truly to this
newsgroup are my personal opinions and not those of Bell Laboratories.leichter@yale-com.UUCP (07/02/83)
Most of what you say about hearing the high end is true, but I have to dis- agree with one statement: Separation above 16KHz is important because the sound there is so directional. While it is true that the SOUND is highly directional, what matters is whether your HEARING is directional; and, in fact, it isn't. Human direction location is best in the midrange. It fades out in effectiveness at both ends, even under ideal circumstances. (There are several different mechanisms that the brain uses simultaneously, inclu- ding at least phase differences, gross timing differences, and the shadowing effect of the head. At very high frequencies - certainly at 16KHz - the only one left that works is the shadowing system; in the mid-range, several contribute and overall system performance is much better.) In addition, "ideal circumstances" are unlikely. 16KHz tones will bounce off everything in your listening room very effectively, and further you'll get standing waves all over. Turning your head slightly, or moving it a small amount, can produce large changes in volume. The directional information just isn't there to be found easily, even by a better system. (I can remember trying to find the bad power supply in a room full of systems when its Sonalert went off (a more or less pure tone up around 16KHz or so). You could hear the damn thing loudly everywhere in the room - but even standing in front of the bad unit, you couldn't tell that it was the source. The only way we were sure we had found the right one was the feeling of relief at the silence when we turned it off.) Anyway...While separation at 16KHz wouldn't be a negative, I doubt you would hear the difference between, say, 12db and 20db. -- Jerry decvax!yale-comix!leichter leichter@yale
newman@utcsrgv.UUCP (07/07/83)
Newsgroups: net.audio Subject: Re: hearing.high.treble References: <227@whuxk.UUCP> Regarding some comments made about the V15-V cartridge a while back, I think the "two serious flaws" mentioned are non-existent when properly measured. The flaws named were 1) non-linearities around 16 kHz 2) separation of < 10 db at 20 kHz If you are interested in the actual performance of this cartridge, you MUST read the November 82 Audio magazine review by B.V. Pisha. It is a superb and thorough technical review and I have not read any measured performance results that come close to this cartridge's in ANY area. With regard to response non-linearities, the thing measured +0, -0.5 db from 1 kHz to 20 kHz, the flattest response ever measured by that reviewer. The separation at 20 kHz measured almost 22 db, which is phenomenal. Other results were as impressive, and the subjective sound quality was judged superb. Ending quote: " After listening to the Shure V15-V over a five-month period I must conclude that it towers over all previous Shure cartridges and probably has no peer among moving-magnet cartridges currently available. In fact, those enamoured with the vaunted moving-coil cartridges and their mystique would find it profitable and ear-opening to audition this remarkable cartridge. " (excerpted without permission, Nov. 82 Audio). Seems to me the author of the net item dismissed the performance of this cartridge from reading a poorly conducted report, not by personally auditioning the cartridge. Hmmmm..... so much for golden-ear moving-coil buffs.
ray@utcsrgv.UUCP (07/07/83)
Actually, from time to time, some magazine or other audio evaluating institution will pick some "golden ears" and A-B-C amplifiers, cartridges, etc. The results usually show that there is little tangible difference in sound (especially with amplifiers, but also with similar cartridges). There may be audible differences but no one really agrees on what the "correct" sound should be so everyone has their favorite. Personally I cannot hear the difference between my friend's Denon 103D and my V15-IV other than that his sounds more expensive [:-)]. As with most audio equipment, the more expensive and the more esoteric, the better the sound HAS to be. BULL FEATHERS!!!!! Ray Allen utcsrgv!ray (416) 978-5036