What About Stereo?

Well, I just happened to have a stock multitrack pop-rock stereo CD in the player when I started working on this experiment. So, I figured I’d just work on the fronts and not worry about or be distracted by the surrounds. I set the pans at +/- 50 between L/R vs. Center, with Divergence at 100 and Center% at 100.

When I’ve done this in the past, with Left and Right at +/- 30°, the results are quite disappointing, with stereo collapsing to a very monaural sounding spread of about +/- 15°. This is because, of course, the Left signal becomes a Left-Center phantom appearing midway between the left and center speakers, at 15°. Doh! Ditto with the right. This is why I had lost interest in 3-channel stereo.

However, with Left and Right at +/- 72°, those Left-Center and Right-Center phantoms appear at +/- 36°, yielding a slightly wider stereo image than we get with the traditional setup.

And what an image! Holy Cow, as Custer was alleged to have said.

A couple of great things happen. First, the center, no longer a phantom, is gloriously solid, fat and stable. And clear!!! Vocals sound great!!!! It is a little surprising how much better it is. Second, Left and Right (now phantoms) are deep and rich, appearing to come from the corners of the room behind the center speaker and giving a wonderful illusion of vast depth and solidity. Third, envelopment is quite dramatic, with the phase-shifted and time-delayed artifacts that we are used to having appear out beyond the speakers now gloriously wrapping around the sides of the room and toward the back, very surround-like.

And finally, the additional bass, given that we have three full-range speakers instead of two, is immensely satisfying. So much so, in fact, that after we (my partner Manny LaCarrubba and I) evaluated some known recordings, we gently eased back on the bass a bit with some very conservative LF shelving below 200 Hz. (We probably wouldn’t recommend this with normal speakers that don’t have the kind of bass extension that my ALT prototypes have.)

The Meaning Of It All

I’ve played this set-up for a number of folks now. All have reported that it sounds considerably better than “normal” stereo. No one has disliked it, except in one instance where it was actually a little too realistic, given a close-stereo-miking purist recording of a forte-piano, where the accuracy of the illusion turned out to reveal a vantage point that was a little disturbing spatially.

The biggest thing to talk about is the sort of reversal of phantom-locations that happens. We’ve come to accept two-channel stereo, where the sides are solid and the center is phantom. Now, I’ve stumbled on a system where the center is solid and the sides are phantom. This is different, it’s quite entertaining, and it is entirely as viable as “conventional” stereo. The benefits in terms of an improved and more stable center image are startling at first, and quite satisfying in the long run for most recordings, particularly well-made stereo recordings.

Will this set-up work with conventional speakers? Probably, especially if they’re decent in quality and have reasonable dispersion. 72° is not unreasonably wide for conventional stereo arrays. Further, there’s no reason you couldn’t ease Left and Right both in to 60° to help with this (although it might have a negative effect on the surround – I’ll report on that later). The only limitation I can think of is that the phantoms might not be as deep behind the speakers as they are with my speakers.

I got so interested in the stereophonic aspects of this set–up I haven’t yet gotten into surround playback. As I mentioned earlier, most surround recordings will need to have left and right also sent to center in sum with the discrete center channel. I’ll try it, go through a month of listening and get back to you.

Meanwhile, let’s talk about the implications of this. Naturally, you aren’t going to immediately reconfigure your systems and start mixing in 3-channel stereo, etc. Right now, such a set-up is purely for fun and amusement. But, it’s cheap, simple, fairly easily implemented and it should work well in surround. The result is a playback topology that takes significantly greater advantage of the center channel, in both stereo AND surround, sounds better and is a lot of fun. It’s worth considering, seriously.

Thanks for listening.

Dave Moulton is definitely having too much fun. You can complain to him about anything at his website, moultonlabs.com.

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