By Norman Eisenberg
From the standpoint of such accepted criteria of speaker performance as frequency response, power-handling ability, dynamic range, clarity, smoothness, definition, transparency, absence of spurious tonal coloration, transient attack, and any others you care to add, the best test equipment remains your own hearing, and the best test material remains musical recordings. This is not to deny the usefulness of such specialized signals as warble tones, pink noise, and the like; nor does it deny the aid provided by such devices as the sound-pressure-level meter or real-time analyzer. But while these techniques can provide clues as to how a speaker might sound, ultimately the only way to judge how it actually does sound is to listen.
Of course, some compositions are better than others for this purpose. The best choice is material that is fairly complex in harmonic structure and richly scored. Music that is relatively thin in texture--solo guitar, for instance-may sound good on any passable speaker. Beyond the music itself, of course, is the recording, and as it happens, classical performances are generally less gimmicked than pop recordings. Often, in the latter, you can't be sure whether the distortion you hear should be attributed to the playback system or was deliberately created for effect in the studio.
Some of my current favorites are among those that I have found especially good for judging speaker performance. 1 have tried to select them carefully so that, in addition to their technical uses, a good measure of musical merit also may be enjoyed by the serious stereo listener.
The Copland recording was made using the 3M digital audio mastering system and in "real time"-which is to say that the entire piece was played through and taped once, with no retakes, no splices, no mix-downs.
The tape then was used to cut the master disc. Doubtless the care lavished on the cutting and subsequent disc processing is as responsible as anything else for the ultraclean sound and its unique impact. A kind of artistic/technical synergism seems at work: The lean orchestration (the original scoring for thirteen musicians) and the clean sonics make for an exceptionally sharp aural focus that not only is very revealing of instrumental timbres, but-especially in some of the more forceful passages toward the end-adds to the illusion that the entire ensemble is right in your room. Basically, this production is a fine proving piece for midrange response; if your speakers have it, there should be a startling sense of presence. A closely related quality is the speakers' ability to distinguish between instruments with roughly the same tonal range but different overtone structures. The work as a whole should create a tight, bright acoustic feeling with well-etched transients.
Whatever else they are-musically, personally, or philosophically--the Enigma Variations are a rich storehouse of tonal color, challenging dynamics, and very wide spans of frequency. And the work demands "wide stage" stereo treatment, so that the miking captures all the inner detail while preserving the sense of ensemble. On a good playback system, these desiderata will be joyfully apparent. On anything less, many sections may sound muddled. There also are several climaxes that stretch your woofers' suspension, and others that will demand nothing but the smoothest response from your tweeters. One especially tricky passage in the finale tests a speaker's ability to handle sub-basement lows with plenty of power. It is perhaps revealing, with all the fuss over today's "superdiscs," that this one was made in 1975 and was neither direct-cut nor processed from a digital master.
---Some current favorites-all with musical merit--that will stretch your system's acoustic sinews---
COPLAND: Appalachian Spring. St. Paul Chamber Orchestra, Dennis Russell Davies. SOUND 80 DLR 101A.
ELGAR: Enigma Variations.
STRAUSS: Don Juan. London Philharmonic Orchestra, Concertgebouw Orchestra, Bernard Haitink. PHILIPS 6500 481.
HANDEL: Water Music. Concentus Musicus, Nikolaus Harnoncourt. TELEFUNKEN 6.42497.
MAHLER: Symphony No. 5. Philadelphia Orchestra, James Levine. RCA ARL 2-2905.
RAVEL: Bolero; La Valse; Rapsodie espagnole. Boston Symphony Orchestra, Seiji Ozawa. DEUTSCHE GRAMMOPHON 2530 475.
MAURICE RAVEL ' BOLERO
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With all due respect to previous "Suites from the Water Music," hearing this full version is a revelation. The recording preserves an airy feeling that--together with an ultraclean disc surface-affords amazing clarity of instruments. This effect is the more interesting because the performance uses original instruments that-historical authenticity aside-evoke a remarkable acoustic quality, one that is bright but never brash. At least that's how it should sound through speakers with really smooth response and good transient behavior. Especially good for this evaluation are Band 3 of Side 1 (the Allegro), and the Minuet toward the end of Side 2, where a deep, well-paced rhythm abruptly intrudes upon a passage for strings and thoroughbass and in turn is followed by the sudden piping of high-pitched piccolos. This record should sound different from performances with modern instruments; if it doesn't, start shopping for new speakers.
Mahler's Fifth Symphony abounds in sonic grandeur. It spans the full reaches of dynamic range and frequency response and presents a dazzling assortment of instrumental timbres and groupings. The first movement's opening brass and later massed strings will test the mettle of your speakers' midrange and highs. So will the stormy second movement. In the Adagietto, listen for strength but no brashness in the strings. Incidentally, the sustained-note passages here are good for checking wow and flutter of your turntable. In the finale, there's another brass choir to challenge your system's high-end response. The later interplay between strings and winds will demolish a system that lacks ample dynamic range and sufficient power capability to span that range. The final bars of the full orchestral climax should come through with a definite sense of the drums and brass choirs holding firmly under it all.
La Valse's big timpani burst and the galloping passages after it were used as a keynote theme for an early Vox album called "This Is High Fidelity," produced more than twenty years ago and, sadly, out of print now. I have long searched for a stereo version of the work that sounded as good, and this DG recording is it. There is something about much of Ravel's orchestrations that suggests a rapid-fire succession of taut transients, deep but well-defined bass passages, limitless tonal coloration for the mid-frequencies, and piercing highs that make you wonder why you ever needed an oscillator to test tweeters. These effects abound in La Valse and in the Rapsodie.
Bolero, of course, is a tour de force of subtle changes in orchestral color, and you should be able to detect the sonic differences between each statement of the theme and the next. It also is an excellent test of stereo imaging in terms of both left-to-right breadth and front-to-rear depth. Correct stereo imaging involves correct phase relationships, good treble dispersion, linear power response, and other speaker design parameters, as well as effective placement in your room. With these pointers in mind, you may find yourself listening to that old Bolero with some fresh insight. By the way, this one was taped in 1974 and transferred to disc by the conventional method -- but with care.
The Telarc disc was cut from a master tape made by the Sound-stream digital recording system, obviously saving as many decibels as could be cut into the groove. From the very first notes of the Stravinsky, with their subterranean lows, you know that something special-sonically anyway-is going on. Look out for that lightning-bolt chord that starts (and reappears throughout) Kashchei's dance; it could, at high volume, tax your speakers' suspension. It also could drive your amplifier (or receiver) into clipping. It actually tripped the overload protection circuit in one receiver I tried it on, shutting the set down momentarily as if someone had pulled the plug. The same thing happened again at the end of the piece.
Some listeners--audio types, at that--have complained that, for all the dynamics and muscular tonality on this disc, it lacks a certain warmth and richness and takes on an antiseptic quality. Be that as it may, on capable speakers the overall sound is so clean you may find you are comfortably playing your system louder than usual. In my own listening room, I clocked sound pressure levels-at a distance of about ten feet from my speakers-of 95 to 100 dB, which sounded (subjectively) fairly appropriate to this recording. The same levels could bother me with many other recordings. So, in a real sense, the record is a test of the many distortions that add up to what is known as "listener fatigue," and as playback equipment goes these days, that problem is most likely to result from less-than-great speakers. Some of the passages also will tax a phono pickup's tracking ability. Watch out for stylus jumps during the massed crescendos.
Just past the Kashchei chord, your speakers should make a splendid recovery and quickly settle down to project the soft, rhythmic passage of bassoons and low horns over strings. Listen here for any signs of tonal dropout. You should not have to turn up the volume to hear all the inner orchestral detail clearly. Listen carefully in the Finale as the music builds to the climax with sudden outbursts of brilliant brass and of heavy percussion with the triangle bravely tinkling away on top of it all. The final bass drum should set up a brief vibration that seems to hover in the air about the speakers.
The opening bars of the Polovetsian Dances are a good test of tweeter response: Can you distinguish among the various woodwinds? At the end of the first chorus, listen to the roll of timpani and bass drum, which should make you feel as if a thunderstorm has erupted in your room. At fairly loud playback levels, the bass will come up from the floorboards; you may actually feel it in your legs.
The Rite of Spring is still the best all-purpose single opus for showing off or showing up a high fidelity system. It has everything an audio-minded fanatic could wish to test the capabilities of his playback equipment.
Did Stravinsky, sixty-six years ago, have some kind of audio prescience? Certainly, the score lends itself most obligingly to the art and artifice of modern recording and playback techniques. So much is going on here, it is impossible to list every possible example of sonic wonderment that is useful for testing.
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STRAVINSKY: The Firebird Suite (1919 version).
BORODIN: Prince Igor: Overture; Polovetsian Dances. Atlanta Symphony Orchestra and Chorus, Robert Shaw. TELARC DG 10039.
STRAVINSKY: Le Sacre du printemps. New York Philharmonic, Zubin Mehta. COLUMBIA M 34557.
ZUBN MEHTA
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One of my longtime favorites comes soon after the opening: The strings, repeating a chord in sharp, asymmetrical rhythms, evoke eruptions from the brasses and woodwinds and lead to a thunderous descending climax in the deep bass tones of percussion and brass. On a top playback system, the visceral effect becomes overwhelming.
And, near the middle of Side 2, there's a section with heavy drum work along with high woodwinds and brass. Each instrumental group should be clearly audible; if the high-pitched tones waver, it's a sign of inter-modulation distortion-in the pickup, amplifier, or speakers. Toward the end of the piece is a passage where the cymbals should sound as if they are tearing the music apart-just make sure they don't tear your speakers apart. Another tricky section has the deep drums interwoven with softer string sounds; again, the one should not inter-modulate the other. The final outburst should linger an instant "in the air." If your speakers are overdamped (for instance, installed in less than an optimum enclosure), you will not hear this effect. If they are underdamped (for any of a number of possible reasons), the sound may linger too long.
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WAGNER: Die Walküre: Ride of the Valkyries. Siegfried: Forest Murmurs. Gotterdammerung: Siegfried's Funeral Music. Tristan and Isolde: Act I Prelude. Los Angeles Philharmonic Orchestra, Erich Leinsdorf. SHEFFIELD LAB 7.
Sheffield's direct-to-disc recording of Wagner opera excerpts is as much a tribute to the stamina and concentration of the Los Angeles players and Leinsdorf as it is an example of brilliantly clean sound emerging from a super-clean background. In the "Ride of the Valkyries," try to hear both the contrasts and the blending of the big brass choirs and massed strings; this is a good test of phase linearity. The tutti climaxes near the end can overload a system that has insufficient power reserves and dynamic range; this also will test your pickup's tracking ability. In the Tristan prelude, note the subtleties and nuances created by the strings; you need very smooth treble response to perceive these effects fully. The slight r-r-r-r of the trombones in the opening of "Siegfried's Funeral Music" is not distortion, although inferior reproduction can make it seem so. To resolve any doubt, compare this sound with the low brass section that follows-it should sound smooth, but with a slight "edge" to the top. Parts of this music can hit sound pressure levels above 95 dB and may, in some installations, set up feedback through the floor to the phono pickup.
For good measure, I will briefly mention a few more releases whose generally superior sonics can be challenging to your speaker system: Thelma Houston's "I've Got the Music in Me" (Sheffield Lab 2) was one of the first of the direct-to-disc albums. It still is among the best, musically as well as acoustically.
Leopold Stokowski's recording of Shostakovich's Symphony No. 6 and Age of Gold Suite (RCA LSC 3133) dates from 1970 but is one of the best he ever made.
In listening to E. Power Biggs's "Historic Organs of Italy" ( Columbia MS 7379), try to differentiate among the various instruments.
Made in 1972, "What the World Needs Now" (Polydor PD 5019), Bacharach songs performed by Arthur Fiedler and the Boston Pops, sets a standard for meticulous recording of ingenious arrangements that are both exhilarating to hear and strenuous exercises for the acoustic sinews of your stereo system.
[HF]
(High Fidelity, Oct. 1979)
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