Music in the Round #20 By Kalman Rubinson   •   September, 2006 Bryston describes its SP2 multichannel preamplifier-processor ($4995) as consisting of a stereo analog preamp with a volume-controlled 5.1-channel analog pass-through plus a full-featured multichannel digital audio processor, and claims that none of those functions compromises any of the others. The analog preamp is fully equivalent in features and performance to their BP26 preamp. The digital processor includes all the latest Dolby Digital, DTS, and THX modes, and is based on Texas Instruments' powerful Aureus DSP chip, which can be updated via an S/PDIF input. The digital and analog sections have independent power supplies, and there are no video inputs or functions other than a control port for the optional, external SPV-1 video switcher.

On the left of the rear panel are six balanced XLR output connectors with six unbalanced RCA jacks next to them, each set conveying analog FR/FL/C/SurrR/SurrL/Sub signals, and both sets active at all times from the SP2's 24-bit/96kHz D/A converters. Joining these 5.1 RCA outputs are two pairs of L/R outputs for tape deck and VCR, and a pair of rear-channel L/R RCAs.

In the middle of the rear panel are four sets of inputs, each consisting of a pair of L/R analog jacks and a coax S/PDIF input. These analog inputs can be digitized or passed through untouched. There are also two pairs of L/R inputs for tape deck and VHS and, along the bottom, the 5.1 analog inputs.

On the right rear are two TosLink jacks (assignable to any input in place of its digital coax jack), an RS-232 data connector, a 1/8" port for the video switcher, two 12V remote trigger outputs, and an integrated master AC power switch, fuse panel, and IEC power inlet.

Keep that array of rear connections in mind and the operation of the front panel becomes clear. Across the top are an alphanumeric display window and a single long row of pushbuttons, many of them accompanied by an LED indicating that circuit's status. From the left and adjacent to the display are three buttons for the programming menus. These let you select defaults for many of the other controls, as well as set up speaker configuration, bass management, crossover frequency (40–200Hz in 10Hz steps), speaker level/delay, and DSP parameters for the processing modes. Each group of settings can be saved uniquely for each source, permitting different setups for CD, DVD, TV, etc., but—none of them applies to the 5.1-channel bypass input, except for its selection.

Next are six input Source selector buttons and their status LEDs. These LEDs, and those associated with other buttons, are very important: the SP2's alphanumeric display turns off after any control operation, and doesn't reappear until the next operation. If you want to know which mode you're listening in, the LEDs are your only clues. To the right of the source selectors are the buttons for Digital Mode (selects digital or analog input for the chosen source), Surround Mode (automatic for Dolby Digital or DTS Plus, for digital/digitized stereo input, or the option of synthesized surround), Stereo (an option for mixing down digital multichannel to two channels), Mono (mix down digital source to mono), and THX (various THX listening modes with re-equalization and/or timbre matching for movies, music, and games).

The last two buttons are Mode—13 basic DSP surround modes, including the variables permitted for DTS-ES, THX-EX, Dolby Pro Logic II, and Neo:6—and my favorite, Bypass: one touch selects analog bypass for stereo from the selected input, and a second touch selects the 5.1 analog input. These bypass modes circumvent any DSP and are subject only to the volume control. In addition, the large, motorized master volume knob operates in all analog and digital modes; a smaller balance-control knob operates only in analog stereo bypass mode.

Finally, beneath the display are the Standby/Power switch and indicator, the IR sensor, and the Dynamic Range Control button. The last button was my least favorite—its settings of Low, Medium, and Full refer to the permitted dynamic range. Bryston warns that "many smaller loudspeaker systems cannot handle" the Full setting, but I found the sound too compressed with anything less. Until I realized that I could program this control, I was annoyed by the recurring compression as I changed inputs and modes. Maybe someone needs this, but I don't.

The SP2's remote control has clearly labeled and illuminated buttons that duplicate every function available from the front panel, and more. It even initiates a pink-noise test signal; with a simple sound-level meter (I used my TEF system), this makes channel balance a snap. I wonder about the value of the remote's light sensor, which, in concert with a Tilt switch, determines if backlighting is needed. One or the other might be enough. Also, there seemed to be a problem if I punched in a remote command while the SP2 was still executing the previous command. In some cases, the control interface would lock up, requiring a quick reboot to return to normalcy.

Two preamps are better than one!
It's tempting to say that the Bryston SP2 has a split brain. After all, inside its chassis are an analog preamp and a digital processor—but do they get along? The answer is a definite "Yes," once it's set up right. For example, the mode for any input can be set to default to digital or to analog. However, even in the former setting, while it will switch to analog in the absence of a digital signal, it will still check for a digital signal and will switch to that if it finds one. Before I learned to defeat this, strange things happened. For example, while listening to a source via analog bypass and using the input connected to my cable-TV box, a change in the format of the Dolby Digital signal would switch the SP2 out of bypass and back to digital. Similarly, I found that, in the time it took to swap and load an SACD, the SP2 would switch back to the digital input if I hadn't programmed that input to ignore digital sources. All was cured with correct programming.

You can operate the SP2 in either mode and, from the couch, toggle between its analog and digital halves. As a processor, it was remarkably flexible and capable. For example, my cable-TV service seems to drop the audio signal level intermittently at certain times of day. It also switches digital audio modes constantly. Faced with such changes, some other processors quickly mute and then return, albeit with accompanying relay clicks and/or a brief interruption of sound. The Bryston, however, seems to have some default mode; all I've experienced with it under these conditions is a short interval of slightly lower sound level.

The SP2's sound quality in all standard decoding modes was as good as it gets. I especially appreciated the ease and flexibility of the Dolby Pro Logic II Music adjustments. Too often, the DPL II defaults give me too much center channel from a two-channel source; the SP2 let me tune it just right, so that I could enjoy the musical wallpaper from my cable music channels without being in the next room! The SP2's surround modes—Hall, Theater, Church, etc.—were recognizable but, to me, as useless as their versions in every other such component I've tried.

The SP2's analog bypass modes, however, are the original reason for my interest in the product. Almost all decent A/V receivers today include a bypass input or two, but I suspect that in the mainstream marketplace they're mere afterthoughts. Most audiophiles, at least as I judge from the Web forums, still have separate home-theater and music systems—or, at most, keep the electronics separate by using a stereo preamp with an HT-bypass input.

That's not really needed here: The SP2 is an outstanding stereo preamp with a 5.1-channel pass-through. I listened to analog radio, CDs—even LPs—through the player's analog output. In no case did I find the SP2 a compromise just because a digital processor hides inside it. It sounded as transparent and dynamic as the other modern high-end preamps I have around, such as the Bel Canto Pre6 and the Simaudio Moon P-8, though a little cooler and tighter than both. Moreover, the SP2's DAC is good enough to eliminate the need of an outboard DAC in most stereo applications. Switching back and forth between the analog and S/PDIF feeds from the Simaudio Moon Orbiter universal player, I was really hard-pressed to choose between them. Mebbe the Orbiter's DACs were a little richer and warmer. Mebbe the Bryston's DAC output was a little more open in the upper mids. Mebbe not. But here's the big deal: Using the Bryston's digital input, you can take advantage of the SP2's DSP for bass management—and, if you have the taste for it, surround processing—without experiencing a significant loss of quality.

The SP2 was just dandy in 5.1-channel bypass mode, its lack of grain and top-end clarity improving significantly on the same mode in the Denon AVR-4806. I particularly liked blasting Frankie Goes to Hollywood's Rage Hard: The Sonic Collection (SACD, ZTT ZTT177SACD) when my wife was out at the far end of the garden. While dynamic and immersive, this disc can also be a bit too edgy on anything less than the best electronics. The SP2 delivered it crisply and cleanly. Big classical, too—such as Nikolaus Harnoncourt's recording of the Verdi Requiem with soprano Eva Mei, mezzo Bernarda Fink, tenor Michael Schade, bass Ildebrando d'Arcangelo, the Arnold Schoenberg Choir, and the Vienna Philharmonic (SACD, RCA Red Seal 61244)—had dynamic and harmonic ranges rendered apparently limitless by the SP2's (and my Bryston 9B 5.1-channel amp's) lack of strain and inconsequential levels of distortion. In fact, its 5.1 bypass mode distinguishes the SP2's performance from that of my resident Meridian Reference 861 processor. The 861 digitizes all analog sources, and very well, too—but no processing is both theoretically and practically superior to any A/D–D/A processing, at least in terms of detail and resolution.

The Bryston SP2 is a contender for audiophiles who want the best of both worlds: a topflight analog preamp and a modern, flexible digital processor. For $4995 you get both, plus an outstanding stereo D/A converter. For performance and value, it's hard to fault.