I've just done exactly that: Fired up my modular synthesizer, plugged my headphones (5Hz-35kHz) straight into the low frequency oscilator (0.001Hz-500Hz)set it to sine wave and turned the frequency down. The result is a hum that goes lower and lower, past the well known mains hum and the pressure inside the headphones gets stronger.
But then there seems to be a transition phase at about 15-20, I'd guess, where the pressure rapidly diminishes and the hum turns into separate click noises! It doesn't sound like a sinewave at all anymore.
Yet when I use this signal as a modulator it turns out to be still a sinewave. So my guess is that we can hear tones below 15Hz but our brain interprets these as short burst of a tone with a much higher pitch.
Any other ideas?
But then there seems to be a transition phase at about 15-20, I'd guess, where the pressure rapidly diminishes and the hum turns into separate click noises! It doesn't sound like a sinewave at all anymore.
Yet when I use this signal as a modulator it turns out to be still a sinewave. So my guess is that we can hear tones below 15Hz but our brain interprets these as short burst of a tone with a much higher pitch.
Any other ideas?