Single Speaker Stereo Prototype
The first test build: three full-range drivers in one cabinet, wired for stereo.
Before the finished Single Speaker Stereo there was a test concept — a loudspeaker with three full-range drivers configured to play stereo from a single cabinet.
The prototype cabinet, built in untreated laminated pine to test the principle before any work went into the finish.
Many Possible Connections
Three drivers in one box can be wired in a surprising number of ways, and all of them were investigated. The input can be voltage or current drive, driver polarities can be inverted or not, and filters can be added, which makes a wide range of transfer characteristics possible. Each variation is interesting from a psychoacoustic point of view, and each one sounds different.
Two of the candidate connections tested on the prototype. The delta arrangement on the right is the one that went into the finished system.
How It Behaved
The prototype was good for casual listening at home. It gained from room reflections rather than suffering from them, and the imaging was very pleasant — enough to justify building the complete system around the idea.
An Old Idea
The concept is not new by any means. A good introduction to it is Elias's page on single speaker stereo. What came out of this prototype was the specific Baffless implementation — the delta driver connection, mixed-mode current drive and frequency-dependent mid/side gain described on the technical detail page.