We have recaptured the historic and classic acoustic strings from a bygone era with SonoTone Concert strings. Discover new ways to experience your guitar with classic tone. Our custom brass alloy, hex core, brass wound acoustic guitar strings, instill a more traditional and vintage vibe. The Concert string tone projects clarity, brilliance, and warmth. We wanted acoustic guitar players to be able to harness brighter and more accurate tones, from the classic past, in the modern recording studio.