901's other problem for any version is that a 4" driver we call a midwoofer today makes for an awful tweeter. Not only is output of the highest octave very limited due to the high inertial mass of the cone (Gordon Holt's observation with which I fully agree) but what little output it produces in this range beams directly on axis. This is a consequence of the cone diameter. To correct this problem, I used an array of small mylar tweeters similar to Audax's 3/8" version. They are very inexpensive and easy to obtain. I used 8 ohm versions. I used 6 per channel, three on the back facing left, right and center, two facing the ceiling, and one in front directly above the 4" driver. I crossed them over at 6db per octave at around 9khz and drive them with a separate amplifier. Equalization for each recoring is critical to obtain correct tonality. I'd say only about 5% of the tweeter energy is directed forward owing to the crossover design and the reflected energy does not have the same FR as the direct energy. This is done to compensate for the differential absorption of the sound as a function of frequency before it reaches the listener. The goal is to have not only the direct sound flat but all of the reflections too. This eliminates two additional forms of geometric distortion my model predicts that other speaker systms can't come close to preventing unless you are unfortunate to be in the world's worst possible listening space, an anechoic chamber.
So, I've been trying to picture your improvements.
Improving Bose 901s
in Bose
Posted
So, I've been trying to picture your improvements.
Any chance you could post a pic?
Thank you in advance
Robert
portland, OR