Music in the Round #2
But while this would also make it possible for us to avoid the mess of multiple links of six-channel analog interconnects, it may not entirely eliminate the need for an analog preamp, or the equivalent, somewhere along the line. Unless or until all of high-end audio goes the way of Meridian and Tannoy, distributing digital signals via network cables directly to the speakers, or we're willing to give up or redigitize our analog sources, most power amps and speakers will require analog input. For now, an analog preamp remains the simplest, most convenient way to integrate the digital and analog portions of our audio systems, especially for those of us with both stereo and multichannel components.
There are several components that do the job. Most are more generally useful than the Sony TA-P9000ES, which was designed to compensate for the lack of a multichannel analog signal path that could handle the output of an SACD player in any of Sony's other digital components. In addition to its 5.1- and 2-channel bypasses, the TA-P9000ES has only two 5.1-channel inputs fed through its controls. You can use the two-channel bypass for your stereo preamp so that all sources can access a common power amp—but why have two preamps, anyway?
McCormack MAP-1 multichannel analog preamplifier
McCormack Audio's MAP-1 is a remote-controlled, line-level analog preamplifier with two six-channel and three two-channel inputs labeled, respectively, DVD/MC1, MC2, Aux1, Phono/Aux2, and CD. In addition to its single six-channel, single-ended output, the MAP-1 also has a two-channel tape output. There is no power switch; when plugged in, the MAP-1 is always in either operation or Standby mode. The front panel is deceptively simple, with only nine buttons for controls, a dual 3.1-digit display, and a few indicator LEDs. The buttons are Standby, Balance L/R, Level Up/Down, Mute, Setup, ARM, and Input Select. The remote control duplicates all these except for Standby (why?), and offers direct input access, an alternative to the sequential access from the single front-panel button. All the controls are self-descriptive, except for Setup and ARM.
McCormack's Ambience Recovery Mode (ARM) derives center, sub, and surround signals from stereo inputs only, to simulate a true six-channel source. The Setup mode sets channel offsets for each channel relative to the LF channel, and can store two sets of balance and offset information: one each for the multichannel inputs and the ARM mode. I found this very useful, as the needs of these two modes were very different. With a good multichannel source having its own bass and channel management, no offsets are needed in the MAP-1, but the default ARM settings put too much information into the center and surround channels. The MAP-1 manual recommends setting ARM so that the rear channels are barely audible. I found that, with my fairly well-balanced speakers, I needed to knock down the rear channels by 6-8dB and the center by 3-5dB or they would be much too prominent, creating a confusing miasma of sound.
With the levels rebalanced, the ARM mode was not only musically pleasant with many sources, it greatly helped with voice intelligibility from stereo TV and video sources. Unlike Dolby Pro Logic, it didn't collapse all voices and solos into the center channel. ARM was nowhere near as impressive or as useful in simulating ambience as Meridian's TriField (which also requires a little tweaking to get right); ARM helped only with congested source material, while TriField was enjoyable with almost all two-channel recordings. I guess this is due to the limited sophistication of signal processing in the analog domain. Nonetheless, ARM was often a welcome adjunct.
Feeding either the Bryston 9B-ST or the new Bel Canto eVo6, the MAP-1 was absolutely dead quiet, clean, and easy to use—except for one thing. McCormack says that the volume/balance increments are 0.5dB, and yet I saw only whole numbers on the display. Well, the dot in ".1" in the 3.1-digit display means that the volume is 0.5dB more than the number displayed.
The MAP-1 was as transparent as the Sony TA-P9000ES, but seemed lighter in weight, with a much more taut, defined bass. The treble was notably open, although the general tonal balance, whether in multichannel or stereo, was more than acceptably neutral. In fact, there seemed to be less congestion in complex and heavy multichannel mixes than with the Sony. Playing an absolutely delightful new DVD-A of Shostakovich's Jazz Suites 1 and 2, The Bolt Suite, and Tahiti Trot (Yablonsky/Russian State SO, Naxos 5.110006), the MAP-1 conveyed remarkable clarity, dynamics, and subtlety. From the opening snare-drum salvos of The Bolt to the suave and sinuous waltzes in both Jazz Suites (you'll recognize one from the soundtrack of Eyes Wide Shut), this was realistic instrumental sound, with excellent depth and definition for a studio recording. Front/rear balances were nigh ideal.