Walt---Compression drivers were developed for use in motion picture theater sound and recording studios, not for public address. Theater sound is most certainly a hi-fidelity endeavor and always has been, the same goes for studio sound. Good compression drivers such as Altec, JBL and TAD can be traced directly back to the efforts of John Hilliard and Jim Lansing to improve theater and studio sound in the 1930s and 1940s.