klein@ucbcad.UUCP (Mike Klein) (06/06/85)
I have just gotten my copy of Martin Collum's "High Performance Loudspeakers" as recommended by Brain Reid a long time ago, and have been avidly devouring each chapter for bedtime reading. One thing he mentions peaked my interest as being something that any home-speaker builder might easily try. Maybe someone in this group has. He cites a bit of work that showed that excellent imaging and reduced room resonances can be obtained by physically separating the woofer from the rest of the drivers, crossing over at about 200-300 Hz, in the following manner. The woofer should be placed within a quarter wavelength of 500 Hz from the rear wall. Thus reflections from this surface will not cause wave cancellation. The rest of the drivers should be mounted as close to free-field as possible and in any case over a quarter wavelength of 100 Hz from the rear wall. Now, some of this is easier to say than do. A quarter wavelength of 500 Hz is only about six inches. If you put the crossover at 300 Hz you should be able to get away with about a foot, which is still hard. Mounting the higher frequency drivers "free-field" is something I have wanted to do with my speakers ever since I discovered that just pushing them out 2 inches from the speaker baffle DRAMATICALLY improved imaging. -- -Mike Klein ...!ucbvax!ucbmerlin:klein (UUCP) klein%ucbmerlin@berkeley (ARPA)