May Meeting Notice

May 2002 Meeting Notice

Analysis of Traditional and Subtractive Methods of Room Equalization

Traditionally, electronic equalization is used to improve the subjective quality of sound reproduction through the use of simple linear filters of low complexity.  It will be shown that the properties of typical rooms combine with Psychoacoustics to limit practical equalization to the use of minimum-phase filters of relatively low order despite the existence of new and powerful digital signal processing tools.  The high Q and non minimum-phase nature of the room-loudspeaker-listener transfer function due to wave interference effects creates severe problems for more complete equalization. A typical professional listening room and three cinema acoustic environments will be used to investigate the difficulties inherent for more ambitious equalization approaches.

Louis Fielder received a BS. degree in electrical engineering from the California Institute of Technology in 1974 and an MS. degree in acoustics from the University of California in Los Angeles in 1976. Since 1984 he has worked at Dolby Laboratories and has been involved in the application of psychoacoustics to the development of audio systems. He has written a number of papers on the determination of the limits of performance for digital-audio and low-frequency loudspeaker systems. He has also worked on the development of low bit-rate audio coders for music distribution, transmission, and storage applications from 1984. He is currently working in the area of room acoustics for small to medium sized rooms.
 

Directions

http://www.dolby.com/company/directions_sf.html

From Peninsula/S.F. Airport/Silicon Valley (Hwy. 101 North) Take Vermont Street Exit. Make immediate left onto Vermont Street. Go 5 blocks and turn left onto Alameda Street. Three blocks up is Potrero Avenue. Dolby is the large, red, 3-story brick building on the corner of Potrero and Alameda.

From Bay Bridge (Hwy. 80 West) Take 9th Street/Civic Center exit. Go to the south onto Harrison Street. Follow Harrison to 10th Street. Turn left onto 10th Street and proceed under freeway overpass onto Potrero Avenue. Dolby is the large, red, 3-story brick building on the corner of Potrero and Alameda.

From Golden Gate Bridge (Hwy. 101 South) Cross Golden Gate Bridge, take the Lombard Street (Hwy. 101) Exit. Follow Hwy. 101 signs up Lombard to Van Ness Avenue. Turn right. Proceed on Van Ness to Fell Street and turn left. Proceed on Fell until it crosses Market Street and becomes 10th Street. Continue on 10th under freeway overpass and bear right onto Potrero Avenue. Dolby is the large, red, 3-story brick building on the corner of Potrero and Alameda.

Address:
Dolby Laboratories
100 Potrero Avenue
San Francisco, CA 94103-4813
415-558-0200