Most people can't actually hear a pure 16.35Hz signal it is quite literally sub-sonic, also the lowest note on a piano is A0 at 27.50Hz which as a pure sine wave is also likely to be inaudible. What most people are hearing are the series of harmonics that occur when the string is struck. So if you combine sine waves of 27.5, 55.0, 82.5, 110.0, 137.5, and 165Hz it'll probably sound like the lowest note on your piano.
The other thing you have to understand is that the equipment you are using quite possibly isn't up to the task. Laptop speakers drop off quite sharply around 80-100Hz and the microphone will do the same.
And of course there is your ear which also suffers from a non-linear response.
Go and read up on stuff like harmonics, musical instrument synthesis and Fourier transforms.
For G10 at 25088Hz you've gone past the Nyquist limit of 22050 for a sampling rate of 44100Hz and so you'll probably get some wierd effects and a lower note. More reading here on analog to digital and digital to analog conversion.