When we make a recording of our own voice then play it back, we are hearing it more or less as other people do. The sound waves travel as a series of vibrations through the air and meet our ear drum. The ear drum in turn sets three tiny bones vibrating – the incus, malleus and the stapes and they send vibrations into the cochlea. The cochlea translates the vibrations into nerve signals and those are sent to the brain. Why then does that sound so different to what we perceive as our own voice?
When you speak you hear your own voice in two different ways. The first is as above, vibrating sound waves hitting your ear drum. The second way is via vibrations inside your skull actually set off by your vocal chords. Those vibrations travel up through your bony skull and again set the ear drum vibrating. However as they travel through the bone they spread out and lower in pitch, giving you a false sense of bass. Then when you hear a recording of your voice, it sounds distinctly higher and the comparison can be quite surprising.