AUDIO/VIDEO NEWS: Now: dbx-Encoded Digital Discs, DAVID RANADA.
By David Ranada
Associate Technical Editor Ranada tries to make himself heard with an oversize dummy of an Audio-Technica mike.
NOW: DBX-ENCODED DIGITAL DISCS
THERE can be scarcely an audiophile worth the name who has not by now sampled some of the exciting new digitally recorded (but analog -pressed) discs avail able from an increasing number of sources.
And there can be scarcely one of those audiophiles who is not already wondering how long it will be until true digital discs-dig tally recorded and digitally pressed-will be his to hear, when he will be delivered from the noise and distortion that have plagued analog recording and playback from the beginning. That day may not come this year or even next, but in the meantime it is possible to sample its promise through a transitional technology that produces sound of, almost the same quality.
Last year saw the introduction of the dbx-encoded-disc system which took quality master tapes (analog -recorded) and converted them into encoded discs that, when played through the proper dbx decoder, de livered sound with previously unobtainable (from vinyl, at least) dynamic range and signal-to-noise ratio (see November 1979 STEREO REVIEW, page 40, for a complete description of the system). Now, from dbx and M &K Realtime Records (an audiophile record company), come the first three recordings made with a digital master recorder (a sixteen-bit Sony PCM-1600) and pressed with dbx disc encoding. These records are even more spectacular than both the earlier, much -praised digitally mastered but analog-pressed discs and the analog-mastered, dbx-encoded variety.
THE dbx disc system essentially increases the dynamic range of a conventional vinyl pressing from a best -case 60 to 65 dB to around 90 dB. This 30 -dB increase reveals itself in two important ways: (1) the peak levels coming out of the disc decoder are much higher than the average levels, thus placing stringent demands on a power amplifier's peak -power capability; and (2) the noise from the disc itself is greatly reduced.
Indeed, I heard no noise in playing the three M&K/dbx records that could be attributed to the discs. And the pressings themselves were thick, flat, and flawless, a rare con junction nowadays.
Analog-mastered dbx discs have some times given evidence of the operation of the dbx process through a subtle "pumping" of the hiss level from the analog master tape.
With these digitally mastered discs, however, hiss, the main clue to improper dbx operation, is gone. (There is some very low level noise in certain cuts, but it comes, I presume, from the mike preamps or the mixer.) In brief, I heard no evidence of dbx misbehavior, even on headphones.
What I did hear was incredible! In respect to dynamic range, these are the most realistic recordings I have ever heard short of a direct playback of a digital master tape.
I was just as impressed by the total lack of noise (except that made by the musicians) during the pauses in the music as I was by the unstrained intensity of the fortissimo passages.
------- The digital recording process is, in truth, a kind of
sonic X-ray that reveals both the technical strengths and weaknesses in the
production of a recording. In classical music, the heart of the producer/engineer's
art is microphone choice and placement. Ken Kreisel, the producer of these
discs, sensibly chose a very simple setup. As he explained it to me, he used
a crossed cardioid (XY) pair, supplemented by a cardioid micro phone on each
side of the orchestra. In general, the sound pickup is clear, but there are
a few anomalies, at least to my taste. First, I find the winds too prominent.
I usually like a "forward" wind section, but in these recordings
that has been accomplished at the expense of the body and "air" of
the string tone. Second, several instruments are too "on -axis," and
an unnaturally close, over-bright sound is the result. This happens with
some of the high percussion instruments and most annoyingly with the harps.
(All of these "faults" are of course a matter of taste, but they are in any case a direct result of the directional properties of the microphones and of their placement.) On the other hand, imaging is generally excel lent, with the instruments quite firmly fixed in their perceived locations-however unusual some of those locations might be! Musically, the performances are not all they might be. Most successful are the Tchaikovsky Romeo and Juliet Overture, the Ginastera Panambi Suite, and Dukas' Sorcerer's Apprentice. In these, the over whelming sound more than compensates for any shortcomings of the orchestra or the interpretation. Some of conductor Zoltan Rozsnyai's mannerisms disturbed me in the Chabrier, Berlioz, and Debussy pieces (and does no one but Monteux slur the trumpet fanfares in Fetes as Debussy clearly marked them?). I was quite disappointed also at the lack of truly soft playing, and I would have liked a bit more subtlety of dynamic shading in the Debussy Prelude-all the avail able dynamic range should have been used.
FNALLY, a word about repertoire. It is reasonable to assume that only the most familiar blockbusters will get digital recording in general-and dbx encoding in particular off the ground commercially in these early days. All the works here fall in that category, with the exception of the Ginastera (a sort of Argentinian Scythian Suite containing a stupendous second movement with low brass, several types of drums, cymbals, and tam -tam). But audiophiles listen as much for the sound as for music. The repertoire of sonic spectaculars can and should be expanded. What better way is there to exploit a wide -dynamic -range playback system such as the dbx disc than to introduce the audio community to the heaven -storming gongs and brass of Messiaen or to Webern's intense and passionate whispers? And a final reminder: dbx-encoded discs, whether derived from analog or digital masters, are playable only through a dbx decoder. You could run them through your sys tem without one, of course, but you wouldn't like the results.
TCHAIKOVSKY: Romeo and Juliet, Over ture -Fantasy; Nutcracker Suite (Op. 71A, excerpts). Philharmonia Hungarica, Zoltan Rozsnyai cond. M &K/dbx RT-20 1 /PS -1002 $16.
DUKAS: The Sorcerer's Apprentice.
CHABRIER: Espana. DEBUSSY: Nocturnes Fetes; Prelude a l'Apres-midi d'un Faune.
Philharmonia Hungarica, Zoltan Rozsnyai cond. M &K/dbx RT-202/PS-1003 $16.
GINASTERA: Panambi Suite.
BIZET: Carmen, Prelude.
BERLIOZ: Rakticzi March.
RIMSKY-KORSAKOV: Mlada Procession of the Nobles. BRAHMS: Hungarian Dance No. 5. Philharmonia Hungarica, Zoltan Rozsnyai cond. M &K/dbx RT 203/PS-1004 $16.
All three discs are available through dbx dealers, selected record stores, and directly from dbx, 71 Chapel Street, Newton, Mass. 01295.
Also see:
AUDIO QUESTIONS and ANSWERS: Shrink Wrap, Companders vs. Dolby, Questions Question, LARRY KLEIN
Source: Stereo Review (USA magazine)