Rocktron CS 5.2.5 Circle Surround decoder Page 2

Over time, I became aware of something that might be peculiar to my sample 5.2.5: Its dematrixing was a little off-target. The soundstage was slightly biased toward the left front and right rear when in either of its surround modes. The bias vanished in stereo mode and with mono program sources, so it wasn't a problem with the channel calibration. And a final quibble: The Cinema Contour control works counter-intuitively. Fully clockwise, it produces the minimum treble attenuation, not the flattest high end as one might expect. This is not mentioned in the manual. At that setting, it causes about 10dB of attenuation at 10kHz—far more than would ever be necessary to tame the hottest soundtrack.

I think it was the late Peter W. Mitchell who first observed that a technology never achieves perfection until after it's obsolete, and Circle Surround is surely an example of that. Just as Dolby Pro-Logic is being superseded by the digital audio formats, Circle Surround has come along with what is probably as good a matrix decoder as we'll ever see. (I wonder, if it had come along 25 years ago, whether it might have changed the course of audio history.) Basically, what we have here is a product that—give or take a little hyperbole—is every bit as good as its manufacturer claims it is. Dolby surround-sound tracks and CS-encoded recordings are often almost indistinguishable from discrete digital sources. But even though some record companies—notably DMP, EMI, and Telarc—have produced Circle Surround–encoded recordings, they're still virtually nonexistent, and audiophiles who aren't into home theater don't know or care about Dolby Surround.

So what does Circle Surround have to offer late-'90s audiophiles that late-'60s quad didn't—particularly since it can't accommodate the abundant matrixed discs that were produced during that period? Let's look at a balance sheet:

What's Going for It:
1) Circle Surround delivers dramatic improvements in realism from music sources, plus movie surround performance that's almost as good as it gets, for a third the cost of other decoders that do it comparably well. It sounds surprisingly like discrete digital—currently the standard against which all surround-sound is judged.

2) It can do an impressive job of reproducing the original hall ambience of the unencoded music recordings that constitute everybody's music collections, with none of the steering anomalies that result when Pro-Logic tackles unencoded material.

3) The system is at no risk of technological obsolescence because, while its own encoded recordings give the best results with music, the failure of the music industry to adopt and use CS encoding will not affect the decoder's usefulness with unencoded material. And it's unlikely there will ever be a decoder that works better.

4) It's one third the price of other decoders that have essentially the same capabilities.

What's Not:
1) 1. If you never attend live concerts, the spaciousness of surround sound probably won't mean a thing to you.

2) Circle Surround can't decode Ambisonics or SQ—the two most common matrixed surround formats for music.

3) As good as it is, CS's surround presentation is not as precise and versatile as discrete digital AC-3 and DTS. It still can't produce consistent multiple images anywhere around a circle, as can digital surround.

But Would I Buy One?
If I were a music-lover for whom sound is as important as music, definitely. It's not demonstrably the best matrixed decoder available—Logic 7 and 6-Axis decoding are comparable, and are more user-configurable. But the Circle Surround 5.2.5 is the least expensive way to get really high-quality surround-sound, and if you ever get into home theater, it does soundtracks too—well enough that you may never feel obliged to move up to digital. If I were getting heavily into home theater and lusted after the best that cinema surround could deliver, obviously I wouldn't.

Okay, so surround reproduction does "smear" front-channel detail, just as real hall ambience "smears" the raw sound of instruments. It's a tradeoff: you lose a little definition in exchange for gaining realism in every other aspect of the sound.

But realism isn't the issue; perception is, and the popular perception is that surround-sound and music don't mix. Audiophiles in general are acutely susceptible to cognitive dissonance. Anything that threatens a cherished belief elicits a reflexive "Yes, but..." response, and the more persuasive the evidence, the more vehement its rejection. Typical is the person who knows horn loudspeakers are no good, but is finally forced, through the evidence of his own ears, to admit that a particular horn system is "the most realistic-sounding I've ever heard"—and then goes right back to listening exclusively to domes, cones, and diaphragms. All audiophiles know surround sound doesn't belong in a good music system, regardless of how realistic it may sound.

And that, in the long run, may be Rocktron's biggest challenge. They do seem to be serious about launching CS, though. They've signed a deal with Analog Devices to put the whole Circle Surround processor on a chip, and are aggressively promoting it as a more music-friendly chip than the ones typically used in TVs and car stereos.

My biggest challenge, on the other hand, may be to persuade any reader of this magazine to take surround sound seriously. I know very well that, no matter how much I rave on and on about what Circle Surround can do for realism, no Stereophile reader is going to buy one of these unless he's already sold on surround-sound. So I have a suggestion: Borrow a 5.2.5 and the necessary ancillaries from a Circle Surround dealer (or buy them if you must, with a 30-day return-if-not-satisfied agreement), and live with them for a few weeks. If, at the end of the trial period, you can bring yourself to return them, I will be very surprised and you will be mired in the past, along with those reactionary souls who still insist that one channel sounds better than two.

Rocktron Corp.
2813 Wilber Avenue
Battle Creek, MI 49037
(800) 388-4447

PaulMG's picture

Before investing into „surround sound installations” I would like to see a solution for inter-channel cancellation of crosstalk and a more sophisticated recording technique. Even the most advanced concepts of wave field synthesis are far from any practical solution! I guess surround sound mandatorily requires the visual input from the cinema screen to create the illusion of surround sound!

JRT's picture

Bogolu Haranath's picture

When WiSA becomes more popular, multi-channel audio for music, may also become more popular ....... Harman brands, Klipsch, GoldenEar, Polk, B&O and some others are already making WiSA capable speakers ....... May be KR could review some of them? :-) ..........

JRT's picture

There already was an existing good solution in UHJ-format.

B-format could have been used for initial recording (tracking) and mixing, and that could have been processed to UHJ-format in the mastering effort for distribution and for consumer playback.

Legacy mono and stereo masters could also be processed to UHJ format.

UHJ has the advantage of being _easily_ scalable both in recordings and in playback.

When DVD was released to the retail market (late 1996 in Japan, early 1997 in US), the standards accommodated more than enough channels and bandwidth for full sphere UHJ.

The mini-DVD form factor was included in the initial release. It had adequate capacity, and the smaller diameter was convenient for carry in a conventional shirt pocket.

Recordings could have been distributed on mini-DVD and UHJ decoders could have been built into the DVD players or outboard processors.