Why do our voices sound different in our heads?

Connie Orbach persuaded Dr Nick Gibbons, voice surgery specialist from Lewisham Hospital to take her through Che's question... Connie - In radio, I am constantly disappointed by the sound of my own voice so, I was keen to bring in the experts for this one. Here's Dr Nick Gibbens, a specialist in voice surgery.Nick - The way we hear is by sound waves, which are pressure waves going through the air, coming in through the ear canal, through the eardrum and the small bones of hearing, into the inner ear where it creates electrical signals that get sent to the brain, and the brain interprets that as hearing. Now that's the majority of the way we hear. However, the second way we hear is actually sound waves, pressure waves, going in through the bones of the skull directly into the inner ear, rather than through the ear canal. But, when we speak, the vocal folds vibrate and produces sound waves and, because the sounds are being produced inside us, a lot more of it is actually transmitted through the tissues and the bones of the skull directly into the inner ear. The frequency at which the tissues of the head transmit the sound best is quite low, so these low frequencies are accentuated. So, our voices sound, to us, a bit lower and a bit more resonant. So, when you hear yourself on a tape recorder, it always sounds a bit more tinny, and a bit more whinney, and a bit higher. So we always go "oh no, that sounds terrible" but actually that's what everyone else hears. The only person who hears the voice as you sound - is you.Connie - How disappointing. In radio, we add resonance to make people sound a bit more 'god like'. It's like having a producer on our own voices.Nick - Yes, I imagine that's exactly right. It's the depth, and the volume, and the broadness of the voice that sounds very good.Connie -So when I have a cold and inside my head I feel like I'm blocked off from the rest of the world - I can't hear myself properly. What's going on there?Nick - Two things there. The first one is: when you normally produce a voice, the vocal folds vibrate and, like ripples in a pond when you throw stones in them, that's what happens when the pressure waves come from your voice box and they come out through your mouth, and they come out through your nose and they reverberate around your sinuses. When you've got a cold, you don't have the nose and the sinuses, they're completely blocked up, so it's only reverberating round your throat and your mouth, so immediately that's going to alter the sound your voice. The second thing is: even less sound is going out of your mouth and in through your ears, for you to hear it, and more of it (percentage wise) is reverberating up through the tissues of your skull into your inner ear so, it's going to sound even more different than it is normally.