Mr. Pearson, nicknamed Dr. Don for his expertise in the fine art of audio engineering, never attended college, but his love of the science of sound led him to a career in music. He became the go-to sound guy for rock bands, including the Jefferson Airplane and Hot Tuna, as well as the Grateful Dead. Later, he was called on nationally, and he installed sound equipment for everything from political conventions to the Olympics to a visit from the pope.

"He was a nerd's nerd," said his longtime friend, David Jacobs, who used to talk technology with Mr. Pearson. "He was an ultra-techie ... there was no more knowledgeable guy around."

Born in 1942 in Chicago, Mr. Pearson was educated at the prestigious Chicago University High School, where his technological brain power was evident. After high school, he headed to Washington, D.C., where he took a job in Virginia at an ice skating rink. The Zamboni driver would soon strike up a conversation with a woman, Frances, who was taking ice skating lessons. They both found out they were from the Midwest, and they had plenty of other things in common, too.

In 1967, they married.

The couple made their way to San Francisco, and soon after, Mr. Pearson was hired by several rock bands. In 1978, he founded Ultra Sound with partner Howard Danchik, and it became the touring sound company for the Dead in 1980. The company also supported the Dave Matthews Band, Tracy Chapman and Primus.

Known not only for its high-quality sound design, but also for its social consciousness, Mr. Pearson's company donated its services to free benefits throughout the Bay Area. The company also provided the sound for the Tibetan Monks, both Republican and Democratic conventions, the Three Tenors and many rock concerts.

Louder, Mr. Pearson recognized, was not always better.

"He wanted the sound to be good, but he didn't want to do damage to anyone's ears," said Jacobs. "All the audio geniuses came to Don."

In 1990, Mr. Pearson earned the nickname Dr. Don when he mended the original 16-track recordings of the live Grateful Dead show at the 1975 Great American Music Hall, which was ultimately released as "One From the Vault," the first in a series of live recordings.

In 1996, after being perilously close to the bomb explosion at the Olympics in Atlanta, Mr. Pearson decided to stick closer to home and focus on large acoustical installations, including a system at Davies Symphony Hall. In 2000, Ultra Sound was sold, but Mr. Pearson continued to install custom audio systems.

When he wasn't working, friends said, he was just as much a perfectionist, whether in cooking or whipping up a new fudge recipe.

He also, according to Jacobs, took roughly 20 minutes to make a coffee. Mr. Pearson, who had rejected espresso machine after espresso machine until he found just the right one, nitpicked about the coffee grinder he used, which was always top-of-the-line. When he finally found the right equipment, he had a ritual of freezing the stainless steel steamer before heating the milk to precisely the right temperature. The water in the coffee also had to be a particular temperature.

"You'll never have a cup of coffee like this guy made," said Jacobs. "He was a perfectionist about so many things."

In addition to his wife 39 years, Mr. Pearson is survived by his children, Melissa Franzen of Ventura and Toby of San Francisco; his sister, Gloria Gross of Rockville, Md; and two grandchildren.

A private memorial has been held. A public memorial will be announced at a later date.

The family said contributions can be made to the National Hemophilia Foundation at www.hemophilia.org.

This article appeared on page B - 5 of the San Francisco Chronicle