We've probably all experienced that uncomfortable moment the first time we hear ourselves on a recording. “Wait! Is that me? It can't be! That's not me!" Those are just a few of the things you might have said the first time you heard your voice on a recording.
The ear's hearing mechanisms lie deep within the inner ear. Sound reaches the inner ear in a couple of different ways. Most of what we hear is the result of air conduction. Things that make sounds cause sound waves that are transmitted through the air.
Those sound waves reach your outer ear and travel through the eardrum and middle ear to the cochlea, which is the fluid-filled spiral organ in the inner ear that translates those waves to the brain. Through the air isn't the only way sounds reach the inner ear, though. The bones and tissues inside your head can also conduct sound waves directly to the cochlea.
When you speak, your vocal cords create sound waves that travel through the air to reach your inner ear. The bones and tissues in your head, however, also conduct those sound waves directly to your cochlea, so that the voice you hear in your head when you speak is the result of both methods of transmission.
When you hear your voice on a recording, you're only hearing sounds transmitted via air conduction. Since you're missing the part of the sound that comes from bone conduction within the head, your voice sounds different to you on a recording.
When you speak and hear your own voice inside your head, your head bones and tissues tend to enhance the lower-frequency vibrations. This means that your voice usually sounds fuller and deeper to you than it really is. That's why when you hear your voice on a recording, it usually sounds higher and weaker than you think it should.
Don't worry if your voice sounds funny to you on a recording. Everyone experiences the same thing. Just because it sounds funny and different to you doesn't mean other people hear it that way. What you hear is what they're used to hearing all the time!