Automated Processes, Inc.

Automated Processes Inc. (API) is an American company that designs, manufactures, and markets mixing consoles and signal processors, including modular signal processor units in the 500-series format standard that evolved from early API mixing consoles.

Automated Processes, Inc.
IndustryProfessional audio
Founded1969 in New York City, United States
FoundersSaul Walker, Lou Lindauer
United States
Key people
Larry Droppa, President


API 2098 32 x 16 x 24 console with 550A and 550 EQ at RCA Studio B. This console has since been moved to Columbia Studio A
48-ch Legacy Plus all-discrete audio console with flying faders at Supernatural Sound Recording Studio
500-6B 500-series Lunchbox System * 512C Mic/Line Preamp (×2) * 550B 4-band EQ (×2) * 525 Compressor (×2)

In 1967, Lou Lindauer and Saul Walker designed a mixing console for Apostolic Recording Studio, the first 12-track recording studio in New York City. Two years later, in 1969, Walker and Lindauer co-founded Automated Processes, Inc. and introduced their first commercial mixing console, whose modular design combined numerous 500-series format signal processor units.[1] The console was sold to Sound Ideas in New York.

Over the course of the next decade, API mixing consoles and processors achieved considerable popularity in recording studios, including Decca,[2] The Hit Factory, Sunset Sound, RAK Studios;[3] major broadcast facilities, including ABC, NBC, CBS, BBC; and others, including Eastman School of Music, the White House, Washington National Cathedral, the United States Marine Band. Notable users included Les Paul, Jimmy Page, Leon Russell, The Doobie Brothers, Bob Dylan, Marvin Gaye, and Stevie Wonder.[4][5]

In 1978, Datatronix licensed the rights to API from the owners. Founder Saul Walker and most of the original engineers, including Sid Zimet, Michael Tapes, and Paul Galburt, who had designed the API 554 sweep and the 954 automated equalizers, went to work for Sound Workshop.[6][4]

In 1985, the assets of API were purchased by Paul Wolff, who owned the company until 1999. Wolff introduced the API Lunchbox, a portable lunchbox-sized chassis for housing up to four API 500-series modules.[7]

In 1988, Audio Toys, Inc. (ATI) was founded as a manufacturer of live sound reinforcement products including the Paragon live mixing console. In 1999 the assets of API were purchased by ATI, and ATI improved quality control, manufacturing and availability of the API product line, re-establishing API as one of the leading American analog pro audio manufacturers. New product introductions, including the Vision surround-capable studio console, as well as the re-engineering of the 1604 small-frame mixing console into the 1608 brought the API sound to a new generation of musicians and engineers.[8]

Popularity in the 500-series format surged in the mid-2000s, and in 2006 API established the VPR Alliance, which established specification standards for the voltage, current draw, physical dimensions, and connection pins of 500-series modules to ensure compatibility with API 500-series rack systems.[1]



API's modular design allows individual signal processor modules to be added to a recording system as budget allows. API's 500-series modules include the 512C preamplifier, the 525 compressor, the 527 compressor, the 550A and 550B semi-parametric equalizers, and the 560 graphic equalizer.[9]

  • 505-DI: Direct Input
  • 512c: Mic/Line Preamp
  • 512v: Mic/Line Preamp
  • 525: Compressor
  • 527: Compressor
  • 529: Stereo Compressor
  • 535-LA: Line Amplifier
  • 550A: 3-band Equalizer
  • 550b: 4-band Equalizer
  • 560: Graphic Equalizer
  • 565: Filter Bank
  • 8 Slot High Current Lunchbox
  • 6 Slot High Current Lunch Box
  • 500 VPR 10-slot Rack


  1. ^ a b Houghton, Matt (November 2020). "Choosing A 500-series Chassis". Sound On Sound. SOS Publications Group. Retrieved 8 July 2022.
  2. ^ Massey, Howard (2015). The Great British Recording Studios. Milwaukee, United States: Hal Leonard Books. p. 52. ISBN 978-1-4584-2197-5.
  3. ^ Massey, Howard (2015). The Great British Recording Studios. Milwaukee, United States: Hal Leonard Books. pp. 287–288. ISBN 978-1-4584-2197-5.
  4. ^ a b "NYU Steinhardt Department of Music and Performing Arts Professions - Saul Walker". New York University. Retrieved 8 July 2022.
  5. ^ Huber, David Miles; Runstein, Robert E. (1974). Modern Recording Techniques (9 ed.). New York, United States: Routledge. pp. 172–196. ISBN 978-1-138-95437-3.
  6. ^ Alexander, Dan (13 March 2012). "A Brief History of API". Retrieved 8 July 2022.
  7. ^ "2017 TECnology Hall of Fame". NAMM Foundation. 2017. Retrieved 8 July 2022.
  8. ^ Payne, Donna (24 November 2003). "Jessup firm's future sound". The Baltimore Sun. Tribune Publishing. Retrieved 8 July 2022.
  9. ^ Fortune, Evan (21 October 2016). "Remembering Audio Pioneer Saul Walker". MIX Online. Future plc. Retrieved 8 July 2022.

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