A Brief History of Early Motion Sound Recording and Reproducing Practices - John K. Hilliard - Journal of the Audio Engineering Society, Volume 3, Number 4, 1985 April

Very nice paper discribing also the bass, mid bass, mid? heaviness effects created in listener's brain when a microphones is just connected to a preamplifioer with no EQ correction for the Fletcher Munson equal loudness curves, voice effort curves, recording space boominess due to standing waves etc.