The next hi-fi revolution begins a week from today, with a whimper. In the liner notes for each of the 22 compact discs to be released on Aug. 27, as part of Abkco Records' Rollings Stones Remastered series, you can read in fine print: "This disc actually has two layers. One is a normal CD. The other layer is a Super Audio CD (SACD) of the same repertoire." Not exactly the stuff of fanfares. Yet the Stones discs mark the mass-market debut of a new audio format—one far superior to the standard CD, possibly even better than (and I say this as a vinylphile) the analog LP.
The new discs—which draw on the original master tapes of every album the Stones recorded in the glory years of 1964-71—sound fine on a plain old CD player. But in a machine designed to play SACDs (more on that later), there's a clarity that was missing on earlier CD reissues or on the original LPs. You catch every strum and nuance of the guitars; the bass line is tight and distinct; the drums pound; and the tambourines sizzle. Especially on the later, better-recorded albums (or most of the songs after "Paint It Black" on the greatest hits twofer Hot Rocks),you hear—you practically feel—waves of sound billowing from the whole area around and between your speakers, with the natural overtones of each instrument preserved intact. It's a difficult sensation to describe, but consider: When you walk by an apartment and hear music coming from a window, you can easily tell whether someone's playing an instrument or a record. That's because live music produces precisely this coherent, unbroken wave of tones and overtones. SACD approximates this aspect of live music in a way that conventional CDs, even well-made ones, do not approach.
As a nutty audiophile, I listened to these discs through a fairly expensive stereo system, but I also plugged the SACD player into my sister-in-law's humdrum rig, and to a lesser degree, I heard the same effect—and so did she. Besides, the SACD player I used to listen to the Stones discs was Sony's flimsy, bottom-of-the-line machine, which retails for $250. The SACD layer of the Stones discssounds better on this cheap box than the CD layers sound on my top-of-the-line Arcam player, which sells for 10 times as much. The SACD layers also sound better than the original LP pressings sound on my VPI turntable, which, together with my Discoveryphono cartridge, costs about 20 times as much.
So what's going on here? Just what is an SACD (as 99.9 percent of the Stones discs' purchasers are likely to ask), and what makes its Audio so Super? SACDs look just like CDs, but they digitally encode music in a completely different way. Regular CDs are made with pulse code modulation (PCM) recorders, which take samples of music—like a sonic snapshot—44,100 times per second. Each sample is translated into a 16-bit signal, which means the data stream consists of 705,600 bits per second. SACDs are recorded in a new process called direct stream digital (DSD), which samples the music as single-bit pulses 2,822,400 times per second—four times faster than PCM, resulting in four times as much information. The faster the speed, the greater the clarity—in the same way that increasing the number of frames per second boosts the quality of a film image, or multiplying the number of dots in a connect-the-dots puzzle improves the accuracy of the final picture.
Ordinary CDs can transmit frequencies as high as 22 kilohertz, or 22,000 vibrations per second (44,100 divided by two). SACDs have a range up to 1.4 megahertz, 1.4 million vibrations (2.8 million divided by two). The human ear can't hear beyond 20 kHz, so this might seem meaningless. But in fact, the distinction is crucial. The PCM signals on CDs must be filtered, mostly to fill the spaces between each sample of sound—or, to extend the metaphor, to draw the line connecting the dots.The problem is that these filters produce noise, and the noise has a distorting effect on frequencies far below 22 kHz, well within the audible range. David Baker, a veteran recording engineer who has worked with all the formats, says, "In the digital world, you need to double or triple the frequency range to get away from audible distortions." DSD, used on Super Audio CDs, more than quadruples the range. No filters are needed. Therefore, no digital noise obscures the subtlest details. (Here's a more technical description of how this works.)
Of course, better sound hardly guarantees success in the marketplace. (Anyone still own a Betamax?) In fact, I argued in Slate last year that SACD was commercially doomed. My reasons: SACD discs, what few existed, retailed for $10 more than regular CDs; they could be played only on SACD players; these players were too expensive (the cheapest was more than $1,000); and normal people would balk at buying another electronic box, in any case.
All those reasons are now obsolete. Sony, which holds the rights to the DSD process and (along with Philips) the SACD format, is pushing this new medium very aggressively. Sony lowered the price of its own SACD discs to just $1 above regular CDs, it slashed the prices of players (which play all CDs as well as SACDs), and it's luring customers to buy SACD players without their being aware of it. For instance, Sony's latest models of thehighly popular "home-theater-in-a-box" systems—which include a DVD player, a five-channel surround-sound receiver, five mini-speakers and a subwoofer, all for $500—also include an SACD chip. This fall, Sony is putting out a stand-alone progressive-scan DVD player that's also a multichannel SACD player for just $250. It's like getting an SACD player tossed in for free.
Most important, in what seems to be a major lesson from its Betamax failure, Sony has licensed the technology to other manufacturers, a step that led to a major innovation. Sonopress, a German company owned by BMG, designed "dual-layer hybrid" machines, which can stamp out discs with two layers—one to be read by the lasers on CD players, the other to be picked up only by SACD players. As a result, you can play the same disc on your SACD player at home and your CD player in the car. And, as with the Rolling Stones Remastered series, you can buy an SACD disc—and buy into the hi-fi industry's agenda —without knowing it.
Right now, there are only two dual-layer hybrid machines in the entire world, and the Stones project—which produced 2 million discs—monopolized both for months. (The discs were originally scheduled to come out Aug. 20, but the machines weren't done pressing three titles, and the distributor insisted on sticking to the original plan of releasing all 22 at once.) Sonopress is starting up another production line in Germany, and Philips and Crest have entered a partnership to make dual-layer hybrid discs in Hollywood. This new digital phase is only at the beginning, but it could take off quickly. Sony has also recruited 60 record companies to join the SACD bandwagon. Among them are such classic labels as Blue Note, Verve, Decca, Chess, Virgin, Deutsche Grammophone, and—most intriguing of all—EMI. How long before we see The Beatles Remastered?