Your voice sounds different on audio-tape (or when you listen to your voice mail greeting et al) for the following reasons:
When you speak, you hear your voice through two channels – through the air (air conduction) and through the bones (bone conduction) in your head. For the air conduction, the sound exits your mouth passes through the air and then into your ear. For the bone conduction, the sound travels from your vocal folds to your inner ear through the bone.
When you hear your voice on tape, all you’re hearing is the your voice via air conduction. That is why it sounds different to you. The audio recorded voice is the voice everyone else hears when you speak. Think about it this way. You hear your voice in stereo (through the air and through the bone). Everyone else hears it in mono (just through the air). No one hears the sweetness and richness of your voice as you do.
In developing your speech communication you need to get to know the voice that other people hear (the audio conduction voice), its strengths and where it can be improved. It can be confronting listening to your voice on tape. However it is one the most powerful forms of feedback – ie. objective feedback.
To ease into listening to your recorded voice, play just a few seconds of it, and turn the recording off. Reflect on what you’ve heard. Then play a few more seconds and turn the recording off again. And so on. Through this gradual listening and reflection you can begin to know and like this voice that other people hear. After you’ve familiarised yourself to your voice, you can then go deeper into listening to how it can be improved so it is perceived by other people, how you want it to be perceived.