if you have a bicycle with two wheels, where one wheel is slightly bigger than the other, and you mark the wheels with a white spot, as the bicycle rolls, say the white spots start out in the same place (wrt a clock face). As the bicycle rolls, the white spots will "go out of phase" with each other, and with every roll, even more out of phase, till they are so out of phase that they start to slowly come a little bit more in phase with each other with every roll, till they match up again... except they are not out of phase, they are just rolling at two different frequencies, and that mix of frequencies is the "timbre" that you hear.
if you have two signals at the same frequency which are out of phase, and you measure at any point, you will just measure a signal at that frequency whose amplitude is the sum of the two signals at that point. You won't be able to tell there is any phasing of two signals taking place. If your two ears hear the same frequency, but with a phase difference, that will be interpreted in part as what direction the sound comes from; it's not definitive, it's just evidence that gets combined with any other senses you have of where the sound should be coming from.
there's a lot more to say about it but no room here for a treatise.