Earth Sound Research was an American amplifier manufacturer based in Farmingdale, New York, that operated through the 1970s. Initially branded ISC Audio, it began as a division of Benjamin Electronics Sound Company and debuted its "Earth" line at the 1972 NAMM show before formally incorporating in New York in October 1975. The company was associated with owners Mark Neuman and Dave Garrett, and its amplifier chassis and sub-assemblies were supplied by Qualtrol Electronics, a subcontractor in Deer Park, New York.

The brand built electric guitar and bass amplifiers, PA mixers, power amps, and standalone solid-state reverb units. Their designs were largely modeled on existing amplifiers of the era — early Earth tube amps drew from Fender circuits, while later solid-state models closely followed Peavey designs. Well-known models include the Original 2000, the Producer, and the Stagemaster PA-2000 tube head.

Earth Sound Research re-incorporated in New York as Aucorp Sound, Inc. in May 1976, ending the short run of the Earth Sound Research name. Because of the company's limited production window and the scarcity of surviving documentation, its amplifiers have become collector pieces in the vintage amp market and often appear on secondhand platforms like Reverb.

Earth Sound Research has 6 products cataloged on Equipboard, including Bass Amplifier Heads, Guitar Amplifier Heads, and Guitar Amplifier Cabinets. Their gear is featured by 2 artists, with the strongest followings in Rock and Metal. Notable users include Doyle Martin and Alan Damien.