Roger Mayer is the electrical engineer who developed several electric guitar effects, most notably the Octavia, an effects pedal which reproduced the input signal one octave higher, and mixes the two sounds with some added fuzz. The effect was popularized by Jimi Hendrix, and can be heard during the solos on the song "Purple Haze".The Octavia, as well as several other effects, are still being produced under Roger Mayer's name.Roger Mayer was an acoustic engineer, working for the Admiralty on underwater research projects. At a time when guitar effects were virtually unknown, he designed and built fuzz boxes for leading English guitarists (Big Jim Sullivan, Jimmy Page, Jeff Beck) that can be heard on P.J. Proby singles such as "Hold Me" (1964) and on numerous Yardbirds tracks.