There have been many inventions aimed at producing a wider or deeper stereo image from conventional stereo speakers, but few can be as cost‑effective as the Nureality Vivid 3D. The aim of the Vivid 3D is to treat the stereo signal in such a way that the reflected components of the sound appear to come from outside the loudspeakers, just as they would in a real‑life ambient environment.
This tiny box takes its power from an external adaptor and connects to your system via two phonos and a stereo mini‑jack. The connectors hint at the Vivid 3D's target market, which would appear to be computer games and stereo TV. There are no real user controls other than volume: you can simply select 'SRS' to process a stereo signal, '3DM' to add a sense of width to mono sounds, or bypass the effect altogether.
With the box in circuit, switching from bypass to SRS mode causes a noticeable increase in level, which the manufacturers say is due to how the circuitry rebuilds off‑axis information. When we hear something off‑axis, it is different in both timbre and level to something heard on‑axis, due to the human hearing system's frequency response. Microphones don't behave in the same way, and SRS mode aims to correct this by splitting the signal into middle and side components (rather like the output from an MS mic pair), applying the necessary tonal correction to the side signal and then recombining the two. The subjective effect is to reduce the impression that the soundstage exists only between the two speakers; sounds in the centre of the mix are little affected, but sounds panned hard left or right seem to be diffused around the room.
An email message to the manufacturer answered all my technical queries and also revealed that the process has been granted a number of patents. Using my phase meter, I detected the use of out‑of‑phase components (a usual ingredient in stereo widening) in the 3D setting used to widen mono sources — but it's claimed that the SRS system adds no additional phase shift.
Because of the tonal coloration introduced by reconstructing off‑axis sounds, I'd be reluctant to treat complete studio mixes with this process, but it is useful to pick out odd bits of percussion, little synth details and, of course, effects. Feeding a stereo reverb back through the Vivid 3D produced a noticeably more spacious sound.
Because SRS doesn't use delay or phase shift, it should have better mono compatibility than some other stereo enhancement processes, but by the same token, the results may not be as dramatic as, say, RSS or QSound. However, it is a useful and very valid effect based on sound psychoacoustic principles that can be exploited in the studio to make mixes more interesting. The signal path is reasonably quiet, and apart from the oddball 'games' connectors, it's no trouble to use. Other models are available which offer the user more control, and there's also talk of a rackmount unit in the near future. At the current price, however, this is one area of space exploration that most people can afford. Paul White