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The Fifth Element #10

John Marks Aug 25, 2002 First Published: Aug 25, 2002

The fundamental object of the invention is to provide...the listener a realistic impression that the intelligence is being communicated to him over two acoustic paths in the same manner as he experiences in listening to everyday acoustic intercourse....—Blumlein, et al, British Patent #394,325, issued June 14, 1933

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A Future Without Feedback?

Martin Colloms Jan 03, 1998 First Published: Jan 03, 1998

Over the years as a reviewer, I have tracked the swings of opinion and popularity of various audio ideas and technologies. Amid a sea of advanced designs that achieve powerful technical performance and laudable specifications, I'm reminded of a major blind listening test of 18 power amplifiers that I set up for the long-since-defunct UK magazine Hi-Fi for Pleasure back in 1975. We had "advanced technology" then: the transistor amplifier had matured and was well accepted by audiophiles. Prices of the review samples ranged from $300 to $3000 (equivalent to $1000-$10,000 in today's dollars). The auditioning sessions were graced by the presence of many industry leaders, among them the late Spencer Hughes of Spendor, Julian Vereker of Naim, Philip Swift then of Audiolab, Alan Harris then of retailer Audio T., Bob Stuart of Meridian, and John Wright of IMF (now TDL in the UK).

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Bad Vibes!

Shannon Dickson Nov 06, 1995 First Published: Nov 06, 1995

A thorough exploration in a magazine article of such a pervasive and complex topic as vibration control in audio systems is next to impossible; vibration and sound are so intimately bonded that it would be very easy to extend this discussion to just about any area of interest in audio. My intention here is simply to lay a foundation for understanding the basic mechanical forces affecting our quest for improved sonic fidelity, and in the process provide the tools for anyone to achieve good, practical vibration control in his or her system.

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Real-Life Measurements

John Atkinson Aug 19, 1995 First Published: Aug 19, 1995

As mentioned by two readers in this month's "Letters," amplifiers are used to drive loudspeakers but are almost exclusively measured into resistive loads. The reasons for this are twofold: 1) real loudspeakers both produce neighbor-annoying sound levels and tend to break when driven with typical amplifier test signals; and 2) the question as to which "standard" loudspeaker should be used is impossible to answer---at least the conventional resistive loads are consistent and repeatable.

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Tweaks'n'Squeaks

Jack English May 31, 1995 First Published: May 31, 1995

If you read Stereophile regularly, you already know that all audio equipment does not sound the same. But did you know that a given piece of gear can sound better or worse depending upon how it's set up and used? With a few simple tweaks, you can bring out the best in your audio system.

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Book Review: "The Complete Guide to High-End Audio"

Martin Colloms, Kristen Weitz Mar 28, 1995 First Published: Mar 28, 1995

The Complete Guide to High-End Audio
by Robert Harley
450+xxiv pp., $29.95 softcover, $39.95 signed hardcover. Published by Acapella Publishing, P.O. Box 80805, Albuquerque, NM 87198-0805. Credit-card orders: (800) 848-5099.

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DTS & Data Compression

Thomas J. Norton Mar 25, 1995 First Published: Mar 25, 1995

In the October 1994 Stereophile (Vol.17 No.10, p.39), I discussed my experiences with the DTS audio data-reduction code/decode switch box, which, briefly, is a two-channel box that makes use of the algorithm DTS has proposed for their version of discrete multichannel sound for laserdiscs.

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Building the Hi-Fi House

Thomas J. Norton Jan 27, 1995 First Published: Jan 27, 1995

Anyone who's ever looked for it knows how rare audio-friendly living space is. Perhaps someday an enterprising developer will build Audiophile Acres---a whole subdivision of audio houses or soundproofed condos that'll meet these needs---then stand by while hordes of long-suffering audiophiles stampede the sales office, frantically waving down-payments in their sweaty hands.

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Why a Preamp?

Thomas J. Norton Jan 07, 1994 First Published: Jan 07, 1994

That was the question asked by a reader who was perfectly happy with his CD-based system. He was using the gain control provided by the variable output of his CD player and was apparently in no need of phono playback or greater flexibility. He asked us to answer this question, ignoring for the moment the obvious functions of switching, volume and tone control, and phono preamplification. With those hardly trivial qualifiers—and bearing in mind the high output available from many of today's line sources, CD players in particular—do you really need the added expense and complexity of a preamplifier?

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Questions of Impedance Interaction

Thomas J. Norton Jan 06, 1994 First Published: Jan 06, 1994

On a number of occasions we have commented on the effects of an amplifier's output impedance on a system's performance. A high output impedance—such as is found in many tube amplifiers—will interact with the loudspeaker's impedance in a way which directly affects the combination's frequency response. The Cary">http://www.stereophile.com//amplificationreviews/740/">Cary CAD-805, for example, has a lower output impedance than most tube amplifiers, and should be less prone to such interaction. Some months back—before the CAD-805 arrived—I investigated this phenomenon in conjunction with measurements for a forthcoming review of the Melos 400 monoblock amplifier. Since the Melos 400 also had a relatively low output impedance for a tube amplifier (at 0.43 ohms at low and mid frequencies, rising to 1.2 ohms at 20kHz, from its 8 ohm tap), I took that opportunity to run some frequency-response measurements using an actual loudspeaker as the load for the amplifier.