Yamaha DSP-A1 Audio/Video Amplifier Review

Just hefting the Yamaha DSP-A1’s considerable mass will tell you that this is one amplifier to be reckoned with, and it’s confirmed by skimming the 106-page instruction manual. As the flagship of Yamaha’s line of home-theater products, the DSP-A1 seemingly has every useful feature imaginable in a topflight integrated amplifier, not the least of which are the most advanced versions of Yamaha’s Digital Sound Field and Cinema DSP processing as well as full Dolby Digital, Dolby Pro Logic, and DTS multichannel decoding. I found the DSP-A1 a worthy successor to the groundbreaking Yamaha DSP-1, which introduced Digital Sound Field processing back in 1986.

If you can’t find the feature you want in the DSP-A1, you probably don't really need it to begin with (a tuner section doesn’t count, as this is an integrated amplifier, not a receiver). In fact, the DSP-A1 has way too many features to mention here, much less discuss thoroughly. By far the most important features are the amplifier’s digital signal processing (DSP) facilities.

Using the power of digital computation, the DSP-A1 is able to generate artificial sonic “reflections” and to feed them through a multiple loudspeaker array to recreate, in terms of direction, timing, and level, the reflection patterns of a real-world acoustical environment. I’ll call this processing ambience enhancement. The DSP-A1 has thirty-one such processing modes, which Yamaha calls Sound Field modes when they are intended for music and Cinema DSP modes when they are meant for movie soundtracks. For music, there are six Concert Hall modes, three Church modes, three Jazz Clubs, three Rock venues, and three miscellaneous modes (Disco, Game/Amusement, and Entertainment/Party). For video-oriented programming there are four Concert Video modes, two TV Theater modes, and four Movie Theater modes. All these are in addition to both ambience-enhanced and standard (here called “normal”) versions of Dolby Digital, Dolby Pro Logic, and DTS decoding.

Do not think a mode’s name limits its applicability to a certain kind of music or soundtrack. Feel free to experiment. If you don’t find a mode you like immediately, all of them have adjustable parameters (reverberation time, apparent room size, and the like). With tinkering you can pretty well optimize at least one mode for every piece of program material.

The DSP-A1 can feed an array of as many as seven speakers, not counting subwoofers: the left/center/right front and left/right surround speakers found in a normal home-theater system as well as a left/right pair of “front effect” speakers. Ideally, the effect speakers are placed, in order of importance, further apart, higher up, and farther away from the listener than the main front stereo pair. Although the DSP-A1 can be switched to feed the front-effect signals through the main front speakers in systems without the extra two speakers, the quality of the ambience in seven-speaker operation is greatly superior. The front-effect speakers don’t have to be large, or even very good, so every effort should be made to include them in any system based on the DSP-A1.

Other processing includes a five-band graphic equalizer for the center channel as well as a Cinema EQ function, which consists of a single-band parametric equalizer and a treble tone control with adjustable turnover frequency. Cinema EQ adjustments can be made separately on three groupings of speakers: the main front speakers (left/center/right), the front-effect speakers, and the surround speakers. Yamaha intends the equalizers for matching speaker sound quality, a laudable goal. But without a lot of tiresome experimentation it would be difficult for most users to do speaker matching, which really needs test instruments and test signals, and it’s easy to totally screw up the sound in the process. I’d use these facilities, sparingly, only as glorified tone controls.

The rear-panel facilities include a full set of line-level preamp outputs incorporating both mono and stereo subwoofer connectors, the latter decidedly a luxury. Another set of jacks is provided as an External Decoder input, in case another 5.1-channel system beyond Dolby Digital and DTS is developed (heaven forbid). There’s an RF AC-3 input for receiving Dolby Digital signals from a suitably equipped laserdisc player, three coaxial digital inputs and five optical digital inputs. Yet another deluxe item, an optical digital output, can feed a digital recorder (DAT or MiniDisc).

Analog audio-only facilities are provided for two recorders, a tuner, a CD player, and even a phono cartridge. The A/V inputs, all equipped with both composite- and S-video connectors, comprise three VCR connections (VCR3 is also labeled for DVD), a satellite/cable decoder box, and a laserdisc player. All of the speaker connectors are multiway binding posts spaced to accept dual banana plugs. There are provisions neither for second-room operation nor for connecting a second pair of stereo speakers. But on the front panel, behind a flip-down door, there is a headphone jack and another A/V input.

A door on the large remote control folds back to reveal quite a few buttons. Many of them are used to control external components (via memorization of the infrared commands of other remotes). To me the most important controls are the twelve buttons that directly select DSP modes — no annoying sequential access here — and the absolutely essential but astoundingly rare Effect On/Off button, which permits instant comparisons between normal and ambience-enhanced playback.

There is an amplifier among all the features, connectors, and processing. The DSP-A1 is rated to deliver 110 watts per channel into 8-ohm loads to the five main channels and 35 watts to each of the front-effect channels. There is no mention on the spec sheet as to whether these figures are for maximum output from all channels simultaneously or in some other combination. Not to worry. Our tests showed that the DSP-A1 is capable of delivering all the power a typical home-theater enthusiast might need.

In fact, the DSP-A1’s performance on the test bench was altogether exemplary. All the numbers range from very good to superb. Both Dolby Digital and DTS decoding tested essentially the same (the DTS tests were limited by the lack of suitable test signals). Of particular interest to me are the low noise levels. In listening tests at normal to loud volume settings, the amplifier’s own noise was never a limiting factor in the dynamic range, which could be startlingly wide with some classical so-lo-piano and symphonic music.

Bass management was not only done correctly, but the DSP-A1 also managed to produce an undistorted subwoofer output with worst-case setup conditions (all main speakers set to “small,” which feeds every channel’s deep bass through the subwoofer output) and test signals (maximum-level Dolby Digital signals in all 5.1 channels). Just keep the amplifier’s subwoofer level setting at -6 dB or lower (page 44 of the manual), and the subwoofer output should remain free of distortion. Use your subwoofer’s own level control to balance the bass output.

Setup of the DSP-Al’s principal features was simple, even with the onscreen menu system switched to its minimally informative “short display” mode. That’s because the front-panel messages allow both setup and in-use adjustments without turning on a video monitor, a boon in adjusting the DSP features while listening to music.

All of my listening was with the full seven-speaker setup, with the additional front speakers placed according to Yamaha’s recommendations and one powered subwoofer connected. Depending on the program material, what I heard was either stupendously realistic or annoyingly gimmicky.

Let me back up. Ever since my- review of the Yamaha DSP-1 processor more than a decade ago, I’ve repeatedly expressed reservations about ambience enhancement of soundtracks (not only by Yamaha components). Even the advanced processing of the DSP-A1 has not changed my opinion, which is based on the fact that multichannel soundtracks already carry the ambience effects intended by the filmmaker. Any added ambience, even when it’s as well done as the DSP-A1’s, stands a good chance of degrading a film's dramatic effect, if not the sound quality per se.

A couple of examples should make my point. In an excerpt from Dragon-heart contained on a demo DVD promoting DTS, there’s a scene in which the dragon, with the unlikely dubbed-in voice of Sean Connery, flies from side to side in the picture while speaking. When I played this scene using any of the DSP-Al’s Movie Theater enhancement modes, Connery’s voice was “dry” and mostly ambience free, as befits the outdoor setting of the scene, while the dragon was in the center of the screen. But whenever the dragon flew off to one side of the picture, his voice became much more reverberant — as if the dragon had flown into, well, a movie theater.

This change in ambience for voices panned to the sides of the sonic image creates a very distracting inconsistency with the screen image, something that the filmmakers cannot have intended. In a real movie theater, all of the loudspeakers are subjected to the same ambience, and there is no extra reverberation for side-panned voices or sound effects. But Yamaha cannot do that here because, as I've pointed out in reviews of other DSP components, adding ambience reflections to the center channel reduces the intelligibility of speech, whether of people or dragons.

Cinema DSP can work against the filmmaker’s dramatic intentions even in a monaural, black-and-white classic. An important aspect of the cinematic style of Dr. Strangelove is the variation of sonic environments contained in the soundtrack itself. The acoustically claustrophobic interior of the B-52 bomber contrasts greatly with the echo-chamber ambience of the ironically named War Room. These differences are reduced and smoothed over by the addition of any DSP ambience effect, even the DSP-A1’s Mono Movie mode. The vividness of the sonic storytelling suffered, and the same thing occurred in at least one scene of every movie I played using a Cinema DSP mode.

Still, the Cinema DSP modes can contribute greatly to the sonic pandemonium in scenes of mayhem, like the tunnel explosion in Daylight and the destruction of the cities in Independence Day. But who wants to select a different DSP setting for every scene change? With some movies you’d have to make an adjustment every couple of seconds. So while I imagine that a well-conducted showroom demo of Cinema DSP could be an absolute knockout, with the movie excerpts cannily chosen to avoid the reverberant-dragon syndrome, once you get the amplifier home you’ll eventually find such processing largely superfluous, as I did. With most films I was perfectly satisfied, and often bowled over, by the unenhanced but nonetheless often spectacular sound quality of DSP-A1’s outstandingly clean and accurate Dolby Digital, Pro Logic, and DTS decoding.

While some of my concerns about fidelity to the intent of the program producers also apply to multichannel music productions, such as Dolby Surround and DTS titles on CD, the situation is quite different with the enhancement of stereo music, in which consistency of ambience throughout an entire program is far more common and in which the producer is not able to supply ambience effects without detriment to the stereo program. (Ambience signals must come from different directions than the main stereo image if that is to remain stable and uncolored.)

When carefully matched with the music, Yamaha’s Sound Field processing has the uncanny ability to move you into the same acoustic space as the performers. Depending on the music, either “you are there” or “they are here.” All manner of classical programs benefited immensely from the processing, from Gregorian chant in one of the Church modes to chamber music in one of the Jazz Club modes (again, don't feel limited by the mode names) to opera in the Classical Opera mode or even one of the Movie Theater modes. Big-band jazz sounded great in Concert Hall A, as did acoustical folk-rock (Joan Baez) in a Jazz Club.

At first hearing with the default settings, I often felt that pop music was overprocessed, with voices losing much of their intended in-your-face immediacy. But when 1 tried adjusting their parameters downward (smaller room, less “liveness,” shorter reverb time, less reverb, and so on), several modes worked very well, producing increased vividness without too much distancing of the vocals. To take one already overhyped example, Madonna’s Ray of Light, which has surprising imaging effects even in stereo reproduction, was even more sonically interesting in the Entertainment/Party mode (with tumed-down parameters) and in the Enhanced Dolby Pro Logic mode, which I found to be the most general-purpose mode of all those the DSP-A1 provides.

With music, Yamaha’s Sound Field processing provided a source of endless fascination and interactive experimentation. It is the glory of the DSP-A1 and the primary reason I would want to buy one. The built-in Dolby Digital and DTS decoders are secondary reasons. And the system’s ease of use, despite the many-buttoned remote, is the third reason. The DSP-A1 is an altogether outstanding piece of home-theater equipment. At this point it is my favorite home-theater amplifier. It’ll be yours too once you grow out of the Cinema DSP modes, and especially if you don’t.

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