Chris Caswell could barely hear a note in the din that surrounded him.
The former Sonoma County musician and music teacher was standing in a cavernous Berkeley workshop, leaning over one of the handmade Celtic harps that have made his name a fixture in the world of folk music for the past three decades.
His business, Caswell Harps, moved to this space near the Berkeley waterfront five years ago, after 15 years of on-and-off operation in Guerneville and Occidental.
The relocation has helped Caswell — now 57 and living in Oakland — expand his production and solidify his place among the several dozen North American and European instrument makers responsible for the revival of the Celtic or folk harp.
Fifty years ago, the ancient instrument was nearly obsolete, pushed out of favor by the larger Napoleonic-era pedal harp. Only about 20 of the smaller harps remained, according to Caswell.
In the 1970s, though, Caswell and others latched onto the rising popularity of folk music and began the slow process of bringing the Celtic harp back into vogue.
For a harp maker, that rebirth happens instrument by instrument.
Over the years, Caswell has turned out more than 1,300 Celtic harps. Two weeks ago, in the Berkeley shop, he was putting the finishing touches on a 50-inch-tall nylon-string model he calls the Rhiannon.
Nearby, four workmen in sweatshirts and carpenter's jeans were building walls and cabinets, producing the shop's near-constant hiss of pressurized air hoses, crack of hammers and whine of table saws and power drills.
Caswell, 6 feet 2 inches tall, with a bushy salt-and-pepper mane and beard and wearing a billowing bohemian shirt and vest, put an ear to the harp and plucked a string.
He was listening for the bright, clear tone that is now the hallmark of his brand of folk harp, a strong and increasingly light model that uses walnut, Sitka spruce, maple and Brazilian cherry woods.
Part whimsical artisan and part gritty craftsman, Caswell said it is the mix of those two traits that has propelled him to master builder status in the harp world.
"My mother is an artist and my father is an engineer and a physicist," he said. "I've got this innate combination of those two aspects."
Raised in the South Bay in a musical family, Caswell first discovered the Celtic harp during a six-month stay in Scotland after high school.
He took private lessons in both the harp and bagpipes.
"I just got hooked," he said, describing the start of what has been a lifelong dedication to both instruments.
After three years studying music composition at San Francisco State University, Caswell started making folk harps in the early 1970s alongside another Bay Area craftsman, Jay Witcher.
Several years later, he started his own shop, moving it to Guerneville in 1982. A flood on the Russian River in 1987 forced him out of business until the mid-1990s, an interval he used to collaborate on a world music radio show on KRCB, help launch the Sebastopol Celtic World Music Festival and start a part-time career as a music teacher.
That broad resum?reflects the diverse role Caswell has played in the revival of Celtic music in the United States, say several local musicians and composers.