Seeking small motor with 1 revol. per minute

I am designing a portable rotation system to measure microphone directionality, which is to rotate full 360 deg each time I trigger Start. My 360 deg measurement lasts exact 1 minute, so I need a very small power, 1 revolution per minute motor with gearbox, reducing motor speed. I have a gearhead motors from Goldmine, but they rotate still too fast, about 1 rev. per 5 sec - and consume too much power, about 90 mA at 1.5V and 200 mA at 9V, with about 5 Ohm resistance. Better would be 50 mA or less, at 3V - since no power is really needed with very small load. Has anyone designed such rotating device and could share this experience - or knows about something close, so I can modify existing unit? Unfortunately, I can not use stepper motors, because of ultra low noise requirement, below 20 dB SPL. They do generate sound as I noticed, too high level. Motor should be able to move in both directions, as voltage polarity changes, which narrows gearbox choices. Peter