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.