You would be hard pressed to find anyone in the music industry who has not used the API 550A equalizer.
The 550A, designed by Saul Walker, an adjunct instructor in the music technology program, has been used in recording studios throughout the world, among them the Record Plant and Sunset Sound, and by such musical greats as Phil Ramone, Jimmy Page, the Doobie Brothers, Stevie Wonder, Leon Russell, Frank Zappa, Marvin Gaye, Herbie Hancock,, and Bob Dylan. In 2008 API 550A was inducted into the Technology Hall of Fame at the annual Audio Engineering Society Convention held in San Francisco.
Walker, a fellow of the Audio Engineering Society, designed the equalizer in 1968, and forty years later, it remains the standard against which other equalizers are measured. What accounts for its popularity and longevity? “The 550A design provides a fast, repeatable, and virtually foolproof mechanism to enhance or accentuate specific segments of the audio spectrum or to de-emphasize other tonalities while maintaining the essential integrity of the program material,” Walker says.
He notes that though newer technology provides greater flexibility at lower cost, permitting more drastic alteration of the sound spectrum, many artists just prefer the sound of the original 550A.
Users of Walker’s equalizer are fond of its acoustic properties – the ‘sweet tonal change’ coursing through the mix and its settings that allow for ‘more bite or body’ in the basses. “An equalizer is, in a way, a musical instrument,” Walker says.
Photo caption: Saul walker signs his ‘Saul Walker Signature Series,’ equalizer at the API factory in Jessup, Maryland.