Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!philabs!cmcl2!floyd!whuxlb!pyuxll!eisx!npoiv!npois!hogpc!houxm!whuxk!wjm From: wjm@whuxk.UUCP Newsgroups: net.audio Subject: hearing.high.treble Message-ID: <227@whuxk.UUCP> Date: Thu, 30-Jun-83 13:34:36 EDT Article-I.D.: whuxk.227 Posted: Thu Jun 30 13:34:36 1983 Date-Received: Fri, 1-Jul-83 12:37:05 EDT Lines: 45 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.