Crawford, D. (1972). "Build a Room Equalizer"(PDF). Audio Magazine (September): 18–22. Archived(PDF) from the original on 2020-07-29. Retrieved 2021-07-24.
worldradiohistory.com
Crawford, D. (1972). "Build a Room Equalizer"(PDF). Audio Magazine (September): 18–22. Archived(PDF) from the original on 2020-07-29. Retrieved 2021-07-24.