cheers,

george

Over in Aylmer and I have some sort of Pi 7's (cornerhorns, not Pi 4's). It would be fun to get together some time and I could share my experience to this point.

Grant Marshall@videotron.ca

I would consider your seven π's to be the "real deal." They were built to spec, and are a genuine π cornerhorn. If I recall, yours have a different HF horn flare than what is most commonly used and you've set them up as a three-way. But there have been lots of different HF horn flares used, and original plans assumed a three-way configuration would be required. The original design assumed a maximum bass crossover point of just a few hundred Hertz. That's the only way they came through the 80's, and it is still an excellent design choice.

Where two-way loudspeakers are concerned, a midwoofer that is capable of reaching into the 1kHz octave usually also has a rising response curve with narrowing dispersion. This makes a good canidate for a two-way loudspeaker configuration. As a direct radiator, you can match DI in the 1kHz to 2kHz region. In a π cornerhorn configuration, the negative slope of the cabinet's response curve complements the rising response of the driver. The face of the cabinet is bare, which grants the cabinetmaker license to create whatever woodworking artwork suits your fancy. Also attractive is the system's simplicity, and of course, its lower cost. So each of these things become positive attributes for the two-way design choice.

But the three-way configuration allows bandwidth requirements to be made more narrow, which has its own set of benefits. Woofer crossover is performed below the frequency where the walls begin to acts as reflectors instead of launch boundaries. Intermodulation distortion is decreased, and each subsystem will be run less in its breakup mode region. The system is more complex, but it is still a pretty simple system, often configured much like a two-way system with a subwoofer.

Anyway, I just wanted to throw that in, because I think that when a speaker is built that takes on the π cornerhorn shape, it should be considered to be a "genuine" π cornerhorn, even if some changes are present. Ten years from now, there will be π cornerhorns having entirely different components, but they'll still be genuine π's because they share the same basic configuration.