Sony SDP-777ES
An $850 Dolby Pro-Logic processor from Sony's premium ES line. Its delay precision beat gear that cost far more.
Overview
The SDP-777ES is the surround processor from Sony's premium ES series. Its centerpiece is Dolby Pro-Logic, the movie-theater version of Dolby Surround. Pro-Logic gives better steering and localization than plain Dolby Surround when decoding Dolby Stereo film soundtracks, and all six of the processor's channels are available in that mode. The outputs feed two front speakers, two rear/surround speakers, a subwoofer, and a center channel. The center output keeps dialog anchored to the screen. For systems without a center speaker, a "Phantom" setting feeds centered information equally to the two mains instead.
Three more surround modes sit around the Pro-Logic core: "Matrix," "Hall," and "Simulated." They use the front and rear speaker pairs. The subwoofer output works in every mode, but the center output is live only in Dolby Pro-Logic. "Hall" rebuilds a concert-hall acoustic by sending direct sound forward and reverberant sound to the rear, with the delay time adjustable to suit the source. A low-pass filter in that mode can be set anywhere from 1 to 16 kHz or switched flat, and it ships set at 7 kHz. "Matrix" is the aggressive one. Sony's own brochure promised a hard-driving sound that makes everything around the listener vibrate, and the company recommended it for rock. "Simulated" makes a stereo effect from mono sources by recreating reflections arriving from various directions. Two further operating modes, presence delay and stereo reverberation, round things out. The presence-delay circuit is meant to widen the apparent source, with the surround speakers placed outboard of the mains and aimed at the wall behind them.
The delay section is the best part of this unit. Delay times run from 0.1 to 80 mS in 0.1-mS steps, adjustable independently for left and right channels. The range is 10.0 to 30.0 mS for Dolby Pro-Logic and the full 0.1 to 80.0 mS for the other three modes. Audio (August 1989, p.83) called those ranges wider than many competing units offered and the precision far greater than most. It also singled out the independent left/right adjustment as a feature few units had, which is what you need when the two surround speakers don't sit equidistant from the listening position. Up to three sets of left/right delay times can be stored per surround mode. A short push of a delay button steps 0.1 mS at a time. If the button is held, the stepping becomes continuous and speeds up after about two seconds. A polarity button flips a channel's phase for a more expansive field on some material.
The measured performance held up. Audio (August 1989, p.83) reported main-channel signal-to-noise of 115.8 dBA in all modes except Dolby Surround, with surround channels measuring 80 to 92 dBA. It found low noise and distortion with very good frequency response across the board. The published specs agree: harmonic distortion of 0.008% at 1 kHz, dynamic range of 90 dB A-weighted, and a digital section flat from 5 Hz to 20 kHz. The analog section reaches 110 Hz to 100 kHz on the center channel, while the subwoofer output rolls off at 12 dB per octave below 110 Hz. Conversion is 16-bit linear at a 48-kHz sampling frequency.
The front panel carries close to a full complement of switches. That includes a six-channel Master Volume that also responds to the remote, which was more operating convenience than many units of the day provided. A display shows mode and delay times, and switches to level status while a level is being changed. The remote handles input selection, surround mode, and delay and level adjustment, so the listener can compare modes instantly from the listening position. Input selection covers one audio and four video sources, with pin-jack connections for video dubbing and two sets of S-video in/out. The reviewer noticed one omission: there's no dedicated muting function, so silencing the unit means switching to an unused input. The mode switches actuate relays, and those clicks are quite audible.
The box itself is modest: 18½ inches wide, 3¾ inches tall, and 13⅜ inches deep (47 × 8.6 × 34.5 cm). It weighs 13.4 lbs (6.1 kg) and draws 30 watts from a 120 V a.c., 60 Hz supply. Price at introduction was $850.
Audio (August 1989, p.94) found the Dolby Pro-Logic mode one of the unit's best features, particularly for those wanting good sound from Dolby Stereo movies. It judged the music surround modes no match for the reference processor but very obviously superior to plain stereo. On the Brahms piano trios, "Hall" at 40-mS delay and −6 dB surround level was fairly good, though the piano's placement occasionally slipped sideways. "Matrix" localized more stably but was less satisfactory otherwise. Dire Straits' Brothers in Arms got "Matrix" with delay set anywhere from 0.1 to 30 mS track by track and surround pulled back to −10 dB to emphasize vocals. Patti LaBelle's I'm in Love Again only settled down once Center Mode was switched to "Phantom," which spread the voice and made it less brittle. The reviewer's verdict: at its relatively moderate price, complete with Pro-Logic, the SDP-777ES was well worth comparing to more expensive models. Dialog positioning and localization for TV and movies came very nearly as good as the reference Yamaha DSP-1 and DSR-100 PRO, though the Sony couldn't be manipulated to create definite room illusions the way the DSP-1 could.
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