The difference in how your recorded voice sounds compared to how you perceive it when you speak is primarily due to the way sound is transmitted and received.
Bone conduction vs. air conduction: When you speak, you hear your own voice through two different methods: bone conduction and air conduction. Bone conduction is when the vibrations from your vocal cords travel through the bones of your skull and directly stimulate your inner ear. This is the sound you hear when you speak, sing, or make any vocal sound. However, when others hear you, they only experience the air-conducted sound, which is the sound waves that travel through the air and reach their ears. The sound transmitted through the air is slightly different from the sound you hear through bone conduction.
Resonance and perception: The bones in your skull conduct sound differently than the air does, which affects the way your voice resonates. When you hear your own voice through bone conduction, it creates additional low-frequency resonance, making your voice sound deeper and fuller to yourself. On the other hand, when others hear your voice through air conduction, they do not experience this additional resonance, leading to a slightly different perception of your voice.
Psychological factors: There are also psychological factors at play. When you listen to a recording of your voice, you are not only hearing it from the outside like others do, but you are also comparing it to your internal self-perception. This internal perception is influenced by your thoughts and feelings about yourself, which can alter your perception of your voice.
All these factors combined can make your recorded voice sound higher or different from what you hear when you speak. It's worth noting that most people find their recorded voices initially surprising or unfamiliar because they are more accustomed to their own voice as heard through bone conduction. Over time, listening to recordings of your voice can help you become more accustomed to how you sound to others.