Kenneth W Kreisel

US Patent:

55374794, Jul 16, 1996

Filed:

Apr 29, 1994

Appl. No.:

8/235552

Inventors:

Kenneth W. Kreisel - La Canada Flintridge CA
Lester M. Field - Los Angeles CA

Assignee:

Miller and Kreisel Sound Corp. - Culver City CA

International Classification:

H04R 300
H04R 102

US Classification:

381 96

Abstract:

A modification and addition to the prior art type of multiple driver push-pull loudspeaker system for subwoofer, bass, or lower midrange frequencies, which prior system is able to reduce the even-order push-pull out-of-phase driver-produced 2nd, 4th, etc. distortion harmonics by the order of 15 to 25 dB in the radiated sound waves. The present invention reduces the important remaining in-phase distortion harmonics using outputs of sensors mounted on the voice coils of each driver to generate electrical signals which are processed and used to substantially lower the remaining in-phase distortion with feedback through a single signal amplifier chain. The present invention contributes from 15 to 30 dB of in-phase distortion reduction of odd-order harmonics and, at relatively high sound power levels only, also reduces some in-phase, relatively lower level, even-order distortion. In addition, separate electrical outputs processed from sensor motion can provide pure even-order harmonics in real time, which outputs can be made available for other possible uses. Obviously, the relatively pure odd-order harmonics normally fed to a mixer in the signal amplifier chain could also be used as a separate output if desired.