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Issue No. 22
Display until arrival of Issue No. 23.
Retail price: U.S. $7.50, Can. $8.50
Is this the format of the future in power amplifiers? (See the analog electronics reviews.)
In this issue: A number of exceptionally competent (and in some cases controversial) loudspeaker designs are evaluated, with special emphasis on subwoofers. In an editorial that will raise some eyebrows, and even some blood pressures, your Editor analyzes the hypocrisy of the high priests of the High End. We continue our survey of amplifiers and preamps. The question of when, if ever, absolute polarity is audible is clarified in a letter from a top authority. Plus other test reports, all our regular columns, and the return of our popular CD capsule reviews (oodles of them).
Paradoxes and Ironies of the Audio World:
The Doctor Zaius Syndrome
By Peter Aczel, Editor and Publisher
12 Loudspeakers Are Getting Better and Better
By Peter Aczel, Editor and Publisher 12 ACI "Spirit" 13 Bag End ELF Systems S10E-C and S18E-C (continued from Issue No. 21) 14 What the Bag End ELF System Does and Doesn't (sidebar by Dr. David Rich) 15 Velodyne DF-661 (continued from Issue No. 21) 21 Velodyne Servo F-1500R 23 Win SM-Snell Acoustics Type A (last-minute mini preview)
25 Good Things Are Still Happening in Analog Electronics
By Peter Aczel, Editor and Publisher & David A. Rich, Ph.D., Contributing Technical Editor 25 Line-Level Preamplifier: Aragon 18k (Reviewed by Peter Aczel) 27 Line-Level Preamplifier: Bryston BP20 (Reviewed by Peter Aczel) 27 Mono Power Amplifier: Marantz MA500 (Reviewed by Peter Aczel) 28 Stereo Power Amplifier: PSE Studio IV (Reviewed by David Rich) 29 Line-Level Preamplifier: Rotel RHA-10 (Reviewed by Peter Aczel) 30 Stereo Power Amplifier: Rotel RHB-10 (Reviewed by Peter Aczel) 30 Passive Control Unit: Rotel RHC-10 (Reviewed by Peter Aczel) 31 Stereo Power Amplifier: Sunfire (Preview by Peter Aczel and David Rich)
33 Catching Up on the Digital Scene
By Peter Aczel, Editor and Publisher & David A. Rich, Ph.D., Contributing Technical Editor 33 Compact Disc Player: Denon DCD-2700 (Reviewed by David Rich) 35 Outboard D/A Converter with Transport: Deltec Precision Audio PDM 2 and T1 (Reviewed by Peter Aczel) 36 Compact Disc Player: Enlightened Audio Designs CD-1000 (Reviewed by Peter Aczel) 41 Compact Disc Player: Marantz CD-63 and CD-63SE (Reviewed by David Rich)
45 Large-Screen TV for Home Theater: Is a 40" Direct-View Tube Big Enough?
By Peter Aczel, Editor and Publisher 45 40" Direct-View Color TV: Mitsubishi CS-40601
47 Obstructionism By Tom Nousaine 50 H i p B o o t s Wading through the Mire of Misinformation in the Audio Press
Four commentaries by the Editor
R e c o r d e d M u s i c Editor's Grab Bag of CDs, New or Fairly Recent
ISSUE NO. 22 WINTER 1994-95
Issue No. 22 Winter 1994-95 Editor and Publisher Peter Aczel Contributing Technical Editor David Rich Contributing Editor at Large David Ranada Technical Consultant Steven Norsworthy Columnist Tom Nousaine Cartoonist and Illustrator Tom Aczel Business Manager Bodil Aczel
The Audio Critic (ISSN 0146-4701) is published quarterly for $24 per year by Critic Publications, Inc., 1380 Masi Road, Quakertown, PA 18951-5221. Second-class postage paid at Quakertown, PA. Postmaster: Send address changes to The Audio Critic, P.O. Box 978, Quakertown, PA 18951-0978. The Audio Critic is an advisory service and technical review for consumers of sophisticated audio equipment. Any conclusion, rating, recommendation, criticism, or caveat published by The Audio Critic represents the personal findings and judgments of the Editor and the Staff, based only on the equipment available to their scrutiny and on their knowledge of the subject, and is therefore not offered to the reader as an infallible truth nor as an irreversible opinion applying to all extant and forthcoming samples of a particular product. Address all editorial correspondence to The Editor, The Audio Critic, P.O. Box 978, Quakertown, PA 18951-0978. Contents of this issue copyright 1994 by Critic Publications, Inc. All rights reserved under international and Pan-American copyright conventions. Reproduction in whole or in part is prohibited without the prior written permission of the Publisher. Paraphrasing of product reviews for advertising or commercial purposes is also prohibited without prior written permission. The Audio Critic will use all available means to prevent or prosecute any such unauthorized use of its material or its name.
The Audio Critic:.I have read Issue No. 20 and found it quite charming. Your elegant chopping to pieces of the audio tweakies was very nice indeed. I even enjoyed the writings of the others, many of whom I know quite well. * * * [Six weeks later:] I have now read the several issues of The Audio Critic which I recently received. They are very interesting, and I want to congratulate you on getting some very good people to write for you. I am a bit surprised that you and some letter writers refer to my modest work so frequently but appreciate the interest I have generated. There are many issues that need deep thought, and I am delighted to have these discussions take place, since the light envoked (with some heat) eventually seems to pry out the truth. It is very annoying to have persons at the extreme fringes of an issue use one's writings to prove their point with elements of these writings taken out of context. Unfortunately, it happens only too often. Shades of gray are too often made black or white by fanatics. I was pleased to see complete paraISSUE NO. 22 WINTER 1994-95 graphs from my paper quoted in context printed in Issue No. 21. Additionally, your interpretation, printed on page 8, of what my article said is quite accurate but a bit more truncated than I would have preferred. If you have the patience, I supply for you herewith my own summary of my work on acoustic polarity. For perspective, my paper on polarity was presented at an AES convention in 1991 and was published in the Journal of the Audio Engineering Society, Vol. 42, No. 4, 1994 April. Needless to say, this is a professional Journal for which all articles are extensively reviewed for quality and accuracy. A version of this paper was also printed in Audio magazine with minor modifications to satisfy a different (and much larger) audience. Nevertheless, the essential contents of the several versions of the paper are identical. I strongly suggest that anyone interested in this matter read the original paper and not someone else's interpretation of what it might say. Some of the listening tests are fairy easy to duplicate, and the paper is written in very simple, not highly technical, terms. These comments cover both the work I did in 1991 and my more recent experiences (1993-1994), which are indicated by brackets [.]. There are four points made: 1. It is clearly possible to show the audibility of acoustic polarity inversion with steady-state tones (electronically generated) or quasi-steady-state tones (produced on physical instruments but with steady monotone playing techniques). These are boring, nonmusical tones. The audibility of acoustic polarity inversion for these very special cases has been documented by several authors. [I have repeated this listening experience many times with both headphones and various loudspeakers, and the experience is so definitive that there is no question about its existence.] 2. When real musical performance material is used in such tests, it is very, very difficult (nearly impossible) to hear the effects of polarity inversion. Our large group tests showed only very slight positive results with loudspeakers in a highly idealized and simplified listening environment. [These listening tests have been repeated with headphones and a great variety of loudspeakers, and it has been confirmed that it is very, very difficult to hear polarity inversion. Nei3
ous electronic components he discusses. May I suggest that in the future more of the test results and discussion of the listening conditions (especially speaker placement) be provided. It would also be useful to have the manufacturers respond to issues raised in the reviews. These changes would allow the reader to better assess the relative merits of each design and reach his own conclusions. Yours truly, Dr. Douglas M. Hughes Rochester, MN I'm not surprised that the Minnesota audio mafia finds staunch supporters at the Mayo Clinic (or am I misinterpreting your prefix and your address?), but you happen to be mistaken on most of the points you bring up. Not all of them, though. You 're right when you say that loudspeaker evaluation is highly subjective, although I try to back up my subjective opinions with objectively verifiable evidence. Furthermore, my subjectivity has been refined over the years through exposure to literally hundreds of speakers/ have some very good reference points of subjective comparison. You're also right in observing that my loudspeaker reviews are not quite as rigorous as David Rich's reviews of electronic components, but there are good reasons for that. A typical electronic signal path in audio (such as, say, the left channel of a power amplifier) has one input and one output. It's relatively simple and straightforward to examine the I/O relationship. A speaker, on the other hand, has one input and n outputs. Which of the latter do we examine? Where in space is the valid, or "official," output of a loudspeaker system? How many points in space are sufficient to give us an accurate picture of the total output? These are nagging questions of measurement methodology, and then there are the endless other questions such as the physical difficulty of ABX comparisons of speakers (see Issue No. 20, page 39) and the various biases introduced by the reviewer's accustomed listening room, etc. Rigorous standards? We're working on them. Don Keele is perhaps the most rigorous loudspeaker reviewer of us all, but then I do a few tests that he doesn't. Amplifier-like certainty in speaker testing we don't haveand will not have soon. Now then, here are the points where you are wrong. (1) I do not "hold planar THE AUDIO CRITIC
magnetic loudspeaker technology in low regard," au contraire, my MG-1.5/QR review begins with "Yes, I have a soft spot," etc., and later I enthuse over the upper bass and lower midrange of the Tympani IVa. (2) The lower bass of the MG-1.5/QR is defined by the fundamental resonance of 44 Hz; it may be that your particular room happens to offer some reinforcement down to 30 Hz, but the designer can't count on that in my particular room. (3) My frequency response measurement was anechoic (via MLS) and therefore closer to reality than any in-room measurement. I don't know how you arrived at your 4 dB in-room figure, but it's irrelevant; no speaker designer deliberately makes the anechoic response nice and jagged in the hope that the room will homogenize it. (4) The (true) ribbon tweeter of the Tympani IVa doesn't ring, so your generalization is incorrect. (5) The audible effects of ringing depend on the frequency but they are very real; having been deeply involved in speaker design as well as testing, I can only say I wish you were right. (6) The MG-1.5/QR does have poor square-wave response; furthermore, ringing doesn't necessarily affect the square-wave response unless located near the square-wave fundamental or its odd harmonics. (7) Revealingness is a relative qualityrevealing compared to what other speaker? (8) I listen before I measure. (9) I did comment on the excellent height and width of the soundstage. (10) Just as a single example, the ACI (Audio Concepts, Inc.) G3 speaker, reviewed in Issue No. 19, beats the MG-1.5/QR on bass and just about everything else, at less than two thirds the price. As for manufacturers' comments, we publish every word of them uneditedif they write us. I don't believe in letting them preview the reviews, however; it makes for fruitless preemptive hassles. Final thought: your Magneplanar MG-1.5/QR is every bit as good, or bad, after my review as it was before it. You are quite certain that it's a great speaker, so why is it important to you that it should be blessed by The Audio Critic ? Ed. The Audio Critic: Most, if not all, of the articles appearing in The Audio Critic are informative, so I would like to suggest that some knowledgeable individual write a short article on what qualities make something ISSUE NO. 22 WINTER 1994-95
Loudspeakers Are Getting Better and Better
The proof is in the recent designs that nudge the state of the art, particularly in bass reproduction, but also in minimizing distortion over the full range.
I can't say it often enough: if you already own a fairly decent home music system, nothing can significantly change the quality of your audio life except new and better loudspeakers. They are so much more important than preamps, power amps, CD players, etc. What happens in most audiophile households, however, is that the main speakers are firmly embedded in the living-room dcor, so that any major change is subject to vigorous spousal objection, especially if larger speakers are contemplated. The typical audiophile then satisfies his lust for shiny new equipment by buying, say, a new preamplifier and persuading himself that the sound is now much better, when in effect it hasn't changed the least bit. It's a syndrome that depresses the hell out of me. (Incidentally, I was recently exposed to a pair of rather large loudspeakers packaged in a novel way that could conceivably overcome spousal objection, even though at first glance the speakers actually appear to be larger than they are. The system, not yet sold anywhere, is called the Applied Acoustics Model 10A and is the brainchild of Jim Suhre, a Raytheon rocket scientist (really!), and Vic Kalilec, an electronics engineer, both from Tennessee. What they showed me was a monumental floor-to-ceiling wall system, the most salient feature of which is its gigantic, seamless, curved tambour door. Open the door and all your electronic equipment is in there, including your large-screen TV. Close the door and the whole shebang looks structural, not like audio equipment. Jim Suhre claims that the curved tambour acts as an ultrasophisticated dispersion device. I have my reservations about that but can report that the sound had exceptionally even spectral balance, from the lowest to the highest frequencies. The speakers, when their floorto-ceiling grille is taken away, are revealed to be only chest high; I'd say they have the overall impact of B&W Matrix 803's or something along those lines. The drivers and network appear to be of the highest quality. The price was still up in the air when I looked; those who go for this sort of thing will no doubt be able to afford it.)
Bag End ELF Systems S10E-C and S18E-C
(continued from Issue No. 21)
Modular Sound Systems, Inc., P.O. Box 488, Barrington, IL 60011. Voice: (708) 382-4550. Fax: (708) 382-4551. ELF-1 two-channel dual integrator electronics, $2460.00. S10E-C black-carpet enclosure with single 10" woofer, $234.00 each. S18E-C black-carpet enclosure with single 18" woofer, $658.00 each. Tested samples on loan from manufacturer.
I see this equipment in a slightly different perspective now that I have measured it and evaluated it at considerably greater length. I don't take back my original statement that "I have never heard bass like this in my listening room," but the reason for that was not the ELF technology. It was the combination of the air-moving capability of two 18" drivers, flat response all the way down into the 20-to-10-Hz octave, excellent damping, and little or no dynamic compressiona combination I hadn't previously experienced, as a total package, in my listening setup. I now believe that good conventional technology could achieve the same resultseven if it rarely does, for various reasons. (See also David Rich's sidebar on the subject and the Velodyne Servo F-1500R review below.) Since an ELF-1 unit plus two S18E sub woofers plus two high-powered amplifier channels could run into $5000 or more, the question is whether or not the ELF approach yields any substantive benefits in a domestic sound sysISSUE NO. 22 WINTER 1994-95
tern (as distinct from professional applicationssee below) that are not obtainable by simpler means for less money. My present feeling is that, from the stay-at-home audiophile's point of view, the ELF system is "a solution in search of a problem." That doesn't make it sound less good than I said, but the I've-got-to-have-it factor is gone because what makes it sound good isn't its uniqueness. My measurements showed the S10E and S18E to be almost identical in small-signal frequency response when driven via the ELF-1 (with all switches down, the most wide-open setting). The deviation from absolute flatness is 0.5 dB down to 20 Hz, dropping to -4 dB at 10 Hz. The Bag End literature shows curves for the S18E that indicate -2 dB response at 10 Hz, which is more consistent with an f3 (-3 dB frequency) of 8 Hz, the claimed system cutoff. I see no reason to make a federal case out of the discrepancy; the measured f3 of 12 Hz is good enough for me. Of course, as the signal is increased, the air-moving and power-handling capability of the S18E quickly passes that of the S10E; on the other hand, multiple Sl0E's in a cluster could keep up with the S18E in all respects. The f3 also moves up, inevitably, as the level is increased; either the driver or the amplifier (remember, it's boosted 12 dB per octave), or both, will reach a limit in linear output capability. The ELF concealment circuit deals with this very neatly (again, see sidebar); it is probably the cleverest and most original element of the total system. You can crank the volume to any level you wish; at some point when, say, the bass drum is thwacked, the concealment threshold lights come on, but you hear no distortion and are unaware of compression; it's smooth as silk. You could argue, of course, that this is needed only because the system has the inherent weakness of being based on tremendous electronic boostone complicated mechanism to correct the side effects of another complicated mechanism. I measured the distortion of the Bag End subwoofers with the ELF concealment threshold set to leave the circuit inactive at the levels tested (all switches down). That way I was measuring the true electroacoustic accuracy of the equalized transducers. Needless to say, the amplifier was at all times operating well below clipping. On the whole, the distortion figures were not impressive. For example, at 30 Hz, as I gradually increased the 1-meter SPL from 80 dB to 95 dB, the distortion of the S18E as measured very close to the cone went from 2% up to 4%. At 40 Hz, the distortion over the same SPL range varied between 1.1% and 1.7%. At 20 Hz, I measured 2.6% (80 dB) to 10% (95 dB). Compare that with the Velodyne F-1500's distortion figures (see below) and you'll begin to understand the design priorities of each. The S10E has a very similar distortion profile down to 30 Hz but gets worse at 20 Hz, as you'd expect. Overall, even the bargain-priced Hsu Research HRSW10 subwoofer (Issue No. 19, pp. 21-22) beats the Bag Ends on
lar-based circuit that is similar to the standard configuration but much more complex. This complexity is introduced in an attempt to prevent the circuit from activating into reactive loads when the current drain may be high but the voltage across the transistor is low enough so that the output device is still in the safe area of operation. A single channel uses 20 transistors and 12 diodes. A single toroid and pair of large 27,000 F filter caps form the unregulated supply rail for both channels. A dual mono design would have added to the cost of the unit, driving it beyond the $1000 price point. Nominal supply voltage is 50 V. The voltage gain stages are on a separate regulated 55 V supply. Higher supply voltage is required here as explained in the Parasound HCA-2200II review. Separate transformer windings and bridge rectifiers are used for the regulated rails. The regulators are formed with LM324 integrated regulators. The use of a regulated supply dramatically improves rejection of power-supply noise and is an important aspect of this design that many amplifiers costing much more than the Studio IV fail to include. With such a regulated supply the improvement in channel separation that a dual mono design could effect would be small. The measured channel separation was 68 dB at 20 kHz, 90 dB at 1 kHz, and 117 dB at 20 Hz. No coupling capacitors are used in the circuit. DC is nulled by a trim pot. Construction is excellent. A large heat sink forms the front of the unit. Double-sided circuit boards are parallel to the heat sink to minimize wiring to the output devices. Some tweako signs in the construction include multiple-paralleled stranded wires used for power supply and output wiring, and a plastic top for the chassis. Distortion would be expected to be higher than in the more expensive competition, owing to the lack of a cascoded second gain stage and the use of a simple, open-loop, MOSFET-based predriver stage. Measurements confirmed this. Into an 8-ohm resistive load, THD + N reached a minimum of -86 dB at 40 watts and then rose with a soft clipping profile to -78 dB at 83 watts. At the "official" 100-watt maximum output level the distortion was -58 dB (0.13%). These figures were almost the same at all frequencies; dynamic distortion was negligible. Into a 4-ohm resisitive load, minimum distortion was -83 dB, still at 40 watts, then rose with a soft clipping profile to -70 dB at 180 watts. Dynamic distortion was a little more evident into 4 ohms, especially in one channel, where the 20 kHz curve deviated from the 1 kHz curve by a worst-case margin of 7 dB. (The MOSFET/ bipolar output stage may have a bias-tracking problem that causes this variation.) The inherent noise floor of the amplifier was significantly lower than that of some prestigious high-end units. The PowerCube system measured a dynamic output voltage of 33 V (136 watts) into 8 ohms. That represents a dynamic headroom of approximately 1 dB, as referenced to the steady-state output of 110 watts at 1%
distortion. The PowerCube looked outstandingly good almost idealwith both resisitive and highly reactive loads at 8 ohms and 4 ohms, but at 2 ohms and 1 ohm the output dropped drastically into reactive loads. This indicates that the protection circuit is coming on despite its complexity. Into pure resistance the output was still good at 2 ohms and 1 ohm, down 15.5% and 41.4% respectively. Peak current output was 37 amps. Given the complexity of the circuit design and the relatively modest power output of this amplifier, one would think it had the potential to perform at the Boulder or Bryston level. The PSE Studio IV doesn't quite live up to that potential. Do not get me wrong; it performs as well as other amplifiers we have recommended. Unfortunately, one such amplifier is the Marantz MA500 (see the Editor's review above), which costs significantly less and offers slightly more power into an 8-ohm load. For the additional $397, the American-designed and manufactured PSE gives you better build quality and better power supply rejection, owing to its regulated supplies. For many this will be enough to justify its cost, and I would not discourage them from purchasing this unit. But we might think of the PSE Studio IV as work in progress because, with small modifications to the protection circuitry, it would draw an excellent PowerCube, and changing the output-stage predriver from MOSFETs to bipolars could probably bring the distortion down by about 10 dB. The Studio IV would then be able to challenge directly its more expensive competitors.
(continued from Issue No. 21) (Reviewed by Peter Aczel)
Rotel of America, P.O. Box 8, North Reading, MA 01864-0008. Voice: (800) 370-3741. Fax: (508) 664-4109. RHA-10 Stereo Active Controller, $1799.90. Tested sample on loan from manufacturer. This is supposed to be the high-end predecessor of the modestly priced RC-980BX, and there are some resemblances but they are generally unflattering to the RHA-10. Unlike the cheaper unit, the RHA-10 uses discrete transistors in the gain block. Complementary bipolar differential pairs are biased by single-transistor current sources and resistively loaded. The second gain stage is a push-pull degenerated bipolar circuit, which drives a push-pull emitter follower. The second stage is not resistively loaded. Referring to the generic active amplifier stage explained on page 18 of Issue No. 18, the coupling capacitors C1 and C3 are electrolytics, just as in the cheaper Rotel, only bigger (25 F instead of 10 F). The more important C2 is not used, again as in the cheaper unit. As for the power supply, each channel has its own
Passive Control Unit
Rotel of America, P.O. Box 8, North Reading, MA 01864-0008. Voice: (800) 370-3741. Fax: (508) 664-4109. RHC-10 Passive Controller, $999.90. Tested sample on loan from manufacturer. As Gertrude Stein might have said, had she been an audiophile, "a passive front end is a passive front end is a passive front end." What's there to review about it? Well, maybe parts quality and construction. Crosstalk, yes. But harmonic distortion? Or, especially, the sound? Only the untutored cultists at the tweako magazines indulge in that kind of rubbish. A passive front end is a bunch of jacks, wires, switches, potentiometers, and suchlike. Might as well talk about the audio performance of the light switch in your wall. (Of course, the tweaks do.) All right, the parts quality in the RHC-10 is high. The construction is beautiful. The crosstalk is remarkably low. Under absolute worst-case conditions, I measured better than 60 dB channel separation even at 20 kHz, improving by several orders of magnitude depending on frequency, attenuator setting, and source impedance. You can say that the unit is transparent. The Input switch has 5 positions, corresponding to 5 pairs of unbalanced input jacks; the Rec Out switch has 4 positions plus Off. The outputs are Main Out and Record Out, unbalanced. The continuously variable highquality attenuator has concentric L and R knobs, adjustable separately for balance and friction-locked for volume. I don't see much point in passive front ends because well-engineered and correctly buffered active units are equally transparent and more versatile, but if the idea appeals to you and you think $1000 is chicken feed, this is a very fine passive control, recommended without reservations. Remember, though, that it has no gain and a 10k output impedance. Use only short interconnects.
Rotel of America, P.O. Box 8, North Reading, MA 01864-0008. Voice: (800) 370-3741. Fax: (508) 664-4109. RHB-10 stereo power amplifier, $2699.90. Tested sample on loan from manufacturer.
After further examination, reflection, tests, and headscratching, I am not at all enthusiastic about this unit and don't feel like giving it much space here. Not that it
Sunfire (more a preview than a review)
(By Peter Aczel and David Rich)
Sunfire Corporation, P.O. Box 1589, Snohomish, WA 98290. Sunfire "Load Invariant High Fidelity Stereo Power Amplifier, " $2175.00. Tested sample on loan from manufacturer.
the DCD-2700's frequency response in the de-emphasis mode. Even stranger are some 0.02 dB ripples in the passband frequency response of the DCD-2700 from 2 kHz to 13 kHz. These measurements make me wonder if something has gone wrong in the evolution of the SM5842AP into the SM5845AF. The SM5845AF adds digital circuitry which attempts to estimate the value of a quantized data point at a resolution below the quantization level. This can only be accomplished by making some estimate of the type of signal that was digitized (because Dr. Shannon has a little theorem forming the basis of information theory that says you cannot take a quantized PCM signal at the Nyquist rate and extract any more information from it). When you play undithered low-level signals through the Denon, the outputs are much more continuous in appearance, and distortion of the signal is lower, than the theoretical minimum for an undithered signal. But a quantized sine wave should have distortion. When dither is not used, the quantization error is correlated with the signal and this causes the distortion. It is for this reason that all recordings are done with dither before the A/D. Dither added at the recording site decorrelates the quantization error, and the distortion is eliminated. Noise, not distortion, occurs instead. Dither also allows us to record signals at levels below an LSB. The Denon digital filter produces a low-distortion undithered sine wave, but how can it improve things with dithered music signals? To do this it would have to reduce the noise level of the signal. Since the noise is decorrelated with the signal and the filter chip has no way of estimating the statistics of the dither or the music, I do not see how this can work. It looks to me as if the whole thing were designed to make undithered sine waves look good at hi-fi-show demos, but Denon's information on this techniquethey call it Alpha System Processingis very sketchy, and a small possibility exists that the Denon system could be of some value. Audio Alchemy is claiming to have a device which performs a similar function, so one must be very careful not to dismiss all this without more information. The DACs are of the Burr-Brown PCM1702J type. The PCM 1702 is a device which is a redesigned PCM63 in a BiCMOS process. It is a smaller die that fits into a 16-pin DIP package or an even smaller surface-mount package. The pins eliminated include the pins for pot adjustments, which were virtually impossible to adjust correctly. The spec sheets for both devices are similar, but the THD for the K grade of the smaller type is 2 dB worse at -20dB and dynamic range is no longer given a worst-case spec. Minimum idle-channel SNR is 6 dB worse at a still excellent 110 dB, and the PSRR spec is not given. Worst-case gain linearity is not specified and the typical number has changed from 0.3 dB to 0.5 dB at -90 dB. On the DCD-2700 we measured a gain linearity error of +0.25 dB at an input signal level of -80 dB. This then rose to +0.75 dB at -90 dB and +1.25 dB at
Compact Disc Player
Enlightened Audio Designs CD-1000
Enlightened Audio Designs Corp., 300 West Lowe, Fairfield, IA 52556. Voice: (515) 472-4312. Fax: (515) 472-3566. CD-1000 THE AUDIO CRITIC
"Audiophile CD Player" with remote control, $1599.00. Tested decline. Channel separation was 86 dB at 16 kHz and imsample on loan from manufacturer. proved 6 dB per octave downward. Gain linearity error down to the -100 dB level was virtually zero (remember, the DAC here is the 20-bit Burr-Brown PCM63P-K, as in I can make short shrift of this one because I have in the DSP-1000), but the low-level noise in the left channel effect reviewed it before, though not in this form. The was clearly worse in this test, also. Harmonic distortion transport uses the offbeat but well-designed Pioneer of a dithered 997 Hz tone at -90.31 dB was just about un"Stable Platter" upside-down drive mechanism, which I detectable above the noise floor. reviewed as part of the Pioneer Elite PD-75 CD player in Issue No. 18. The electronics are essentially the same as If it had not been for the low-level noise problem in the Enlightened Audio Designs DSP-1000 Series II in the left channel and the lack of index buttons on the reoutboard D/A processor, which I reviewed in Issue No. mote control, I would have considered the EAD CD20 and recommended as an excellent choice. (In fact, Da1000 to be a close runner-up to the Sony CDP-X707ES, vid Rich bought one.) I could end my review right there, at a saving of $401, as my favorite "Audiophile CD leaving you with the impression that this is a highly dePlayer" (to use the phrase inscribed on the EAD's front sirable CD player, but there's a little more to it than that. panel). As it is, I cannot give it that ranking. But, if EAD came out with a CD-1000 Series II. For one thing, the PD-75 (which was originally introduced in 1991 and is no longer in the Pioneer line) had Compact Disc Player index buttons on its remote control; the EAD CD-1000 does not. That alone would be sufficient for me, personally, not to buy it even at half the price, but those who have (Reviewed by David Rich) few or no classical CDs probably won't mind (rock-pop CDs neveror hardly ever?have their numbered Marantz USA, 1150 Feehanville Drive, Mount Prospect, IL tracks further divided into index numbers). I am firmly 60056. Voice: (708) 299-4000. Fax: (708) 299-4005. Model opposed to the use of the forward and backward scan butCD-63 compact disc player with remote control, $399.00. Modtons for index hunting; it's a drag (and let's not even talk el CD-63SE compact disc player with remote control, $499.00. about the CBS CD-I standard test disc, which is all inTested samples on loan from manufacturer. dexes). Other than that, the transport of the CD-1000 is just fine and dandy (see my comments in the aforesaid Editor's Note: Although this review was written in PD-75 review). the spring of 1994, the CD-63 is still in the Marantz line and will remain therefor some time. Meanwhile, Marantz I expected the standard measurements to show prethas also added the CD-63 Special Edition to the line. The ty much the same results as with the EAD DSP-1000 and SE version is listed at $100 more and is basically a marI was at least partly right. In the right channel, THD + N keting idea, designed to attract those who like the idea of at full scale (0 dB) was 5 dB worse than the theoretical "tweaked" versions of standard components. At least the ideal (-98.08 dB) at nearly all frequencies. That was tweaking here is done by the designers of the original clearly due to gain-related analog distortion because, unit, not by some third-party cultist operating from his with the digital signal level reduced from 0 dB to -24 basement. The "improvements" include a much heavier dB, the departure from perfection was only 1 dB, matchbottom plate for the chassis (the SE weighs 37% more ing the performance of the DSP-1000. The left channel, than the plain CD-63), gold-plated jacks, a number of however, was another story. At full scale, the excess disfancier capacitors, a higher-grade power transformer, tortion was 11 dB at the lowest frequencies and never additional shielding, etc. All very nice, but I could meabetter than 6 dB at any frequency. Even at -24 dB, there sure no improvements of any kind in the actual output of was still approximately 3 dB excess distortion at all frethe SE. The two models are indistinguishable in perforquenciesmuch worse than the other channel. I suspectmanceand that includes the small power-supply bumps ed low-level hum components (60 Hz and multiples), but rising from the noise floor. Thus every word of Dr. Rich's spectrum analysis revealed no such bumps, only a generally elevated noise floor, especially between 90 and 500 review is applicable to both models. Hz, about 10 dB higher than in the right channel. David * * * Rich suspects a noisy op-amp. I'll give EAD the benefit The marketing guys at Denon and Harman Kardon, of the doubt and assume that other samples of the CDhaving read my reviews of their CD players, are no 1000 do not have this fault, but QC should have spotted doubt saying something like this: "That Dr. Rich is some it and weeded it out before the unit was released. ivory-tower fruitcake. If he knew anything about the cost of producing a CD player, he would understand that you In all other respects the CD-1000 proved to be can't produce a CD player the way he wants to at our flawless on the lab bench. At full scale, the frequency reprice point." To these marketing people I answer: Masponse rolled off 0.05 dB at 10 kHz and 0.15 dB at 20 rantz CD-63. Now do not get me wrong, the Marantz kHz. De-emphasis error was 0.15 dB at 10 kHz and 0.35 CD-63 is not a Sony CDP-X707ES for one fifth the dB at 16 kHz, but that included the frequency response
of HFN/RR. He responds to a Mr. Burmajster, who had apparently disparaged subjective audio reviewing and asserted the greater validity of measurements. Ken Kessler writes: "the measurements of hi-fi components have little if any bearing on the sounds they make" (italics his). He adds that "unless we're talking about ludicrous anomalies, like a speaker which has a 20 dB dip at 5 kHz or an amp with 10% distortion, the hundredths-of-a-percentile measurements foisted on us (initially by the Japanese) do nothing to tell us whether or not a product reproduces sound convincingly and realistically." Well, Ken, how about the 1 dB or so frequency-response tailoring introduced by an amplifier output impedance of 1 ohm or so (see our Issue No. 16, page 55) on which an entire multimegabuck "tube sound" commerce is based? How about an error of 0.3 dB in the de-emphasis curve of a CD player that can make certain pre-emphasized CDs sound too bright? And, in general, when you subjectively find that a hi-fi component sounds like this or like that, there exists no verifiable cause for the effect you perceive? Further on, the letter challenges Mr. Burmajster as follows: "if he can look at the measurements (manufacturer's or self-measured) of five D/A converters and then match them to the converters in a blindfold listening session, I will never again write a subjective, measurementfree review." The hypocrisy of that challenge leaves me in a state of sputtering rage. Here is a subjective reviewer who will unhesitatingly declare that A has better soundstaging, or less grain, or more bloom than B but never, never feels the need to prove that he can actually tell A and B apart "in a blindfold listening session"and he has the nerve to challenge someone else to have a perfect score not in an A/B but an A/B/C/D/E blind test! You know damn well, Ken, that neither one of you can tell any two D/A converters apart in blind listening. That's the whole point, man! Whether they have -97 dB or -85 dB distortion and noise, it's well below the threshold of hearing, but I want to know those numbersand a whole slew of others to find out which is more carefully engineered and the better value. Do you have a better way of evaluating them? Yes, I know, "by listening"except that you're unable to hear the difference unless you're allowed to look at the nameplates! It's an unfunny farce. There are certain basic realities in audio today, and it's time for all audio journalists to face them. Presentday electronic signal paths are sufficiently clean to have no distinguishable "sound" of their own. You have to measure them, analyze the circuits, look at the quality of parts and constructionthat's how you evaluate them. That great admonition "Why don't you just listen?" works only with loudspeakers, earphones, and microphones today. That makes the nontechnical, noncircuitreading, nonmeasuring reviewers who "just listen" something of an underclass, but what do they care? They can still get all the expensive toys they lust for on extended free loan from the component manufacturers.
"Music for Violin and Guitar." Arturo Delmoni, violin; David Burgess, guitar. SACC102 (1991). Single mike, Blumlein pattern, no gain riding, custom electronics, tweako engineer (Bob Katz, see Issue No. 17, p. 45), high-end audiophile artists, cryogenically processed violin stringsget the picture? I was ready to have a bit of tweak-bashing fun with this, but the sound is truly gorgeous, featuring an utterly natural, sweet violin tone and somewhat reticent but beautifully delineated guitar twangs. The imaging is very stable. The music is mostly transcriptions of light classics (one contemporary work: David Leisner's violin/guitar sonata); the playing is stylish and highly respectable in technique. A demo CD, much as I hate to admit it.
Here we are in Brad Miller country, and that means amplifier-clipping, loudspeaker-busting sound effects (although the man is also quite capable of making first-rate musical recordings). The Colossus digital processor and discrete multichannel master tapes are ingredients of the SPL fest in each instance.
"Sonic Booms 3." BCD 6289 (1992 and earlier). Missiles, space shuttle launches, supersonic jets, and suchlike, alternating with peaceful surf sounds, etc. As good as this sort of thing gets. Forget it without a subwoofer, though. "4449 Pinnacle! Daylight." BCD 6295, Discs 1 and 2 (1991-92). Strictly for aficionados of classic steam locomotive sounds but the very best of the genre. No, I didn't listen to every one of the 27 tracks on two CDs, but I'm ready to acknowledge that Brad Miller is the master of this. Once again, a good subwoofer is mandatory. (And I hope you already own Beethoven's Ninth.) Chesky Records This label is one of the apostles of "natural" sound via minimalist recording
George Szell: "Music by George Szell." The Cleveland Institute of Music Orchestra, Carl Topilow and Louis Lane, conductors; The Cavani String Quartet. CIM release #2152 (1992). Two orchestral works and a piano quintet by the great conductor, who was an eclectic but highly imaginative composer in his early youth. Brahms, Dvoralc, Mahler, Strauss you can hear them all in these clever pieces composed between the ages of 14 and 24. The playing is uniformly excellent in all three works; the recording of the orchestra is pleasantly bright and punchy, not at all harsh, and extremely detailed and impactful (Judy Sherman was the producer).
This is a most unusual situationrecordings dating back 8 to 10 years, by a now defunct string quartet, recorded by a team (Marc Aubort and Joanna Nickrenz) no longer associated with Delos, and still being released one CD at a time (Volume VI only recently this year), two quartets per CD, with five quartets and the Grosse Fuge yet to come. But what a series! The Orford was for more than two decades the pride and joy of Canada, as good a string quartet as any. I was weaned on the Budapest and the Guarneri but I enjoy the Orford equally. Their playing is totally secure and highly nuanced; in the new Volume VI, for example, the monumental Opus 131 receives a marvelously lucid and musical performance. The Aubort/Nickrenz digital tapings are fully up to 1994 standards, as transparent as it gets. Even John Eargle has to be satisfied, although he would probably have recorded the instruments a little bit less close. Matter of taste. As for the delayed releases, don't ask me why.
Gaetano Donizetti: Lucia di Lammermoor. Edita Gruberova, soprano; Neil Shicoff, tenor; et al; The Ambrosian Singers; London Symphony Orchestra, Richard Bonynge, conductor. 9031-72306-2 (1991). I agree with Toscanini about Lucia: "Che bell' opera!" Never mind the coloratura shenanigans; listen to the melodies, the ensemble writing, the lyricism alternating with dramait's good stuff. Here is the same pair in the leading roles that I liked so much in the Teldec Traviata: Gruberova has touches of greatness (vocally if not dramatically) and Neil Shicoff has a still fresh, unabused, beautiful tenor voice. Bonynge's conducting could be more dynamic but he keeps producing lovely sounds, and that's what this opera is about. The recording is perhaps a bit constricted in the busy moments but always clean.
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