 Most of these sounds were generated using an electronic circuit called a "ring modulator".After recording the basic sounds, the Barrons further manipulated the sounds by adding other effects, such as reverberation and delay, and reversing or changing the speeds of certain sounds.Since Bebe and Louis Barron did not belong to the Musicians Union, their work could not be considered for an Academy Award, in either the "soundtrack" or the "sound effects" categories.