The difference in how your voice sounds when you hear it through speakers compared to when you listen to recordings is primarily due to two factors: bone conduction and the perception of sound.
Bone Conduction: When you speak, you not only hear the sound through the air but also through vibrations conducted by the bones in your head, including your skull and jawbone. This bone conduction pathway allows you to perceive your own voice differently than others do. When you hear your voice directly through your own ears, the bone-conducted sound adds richness and depth to the sound, which is absent when you hear a recording played back through speakers.
Perception of Sound: Our perception of sound is influenced by a variety of factors, including the way sound waves interact with the environment and our own auditory system. When you speak, the sound waves travel through the air and reach your eardrums, where they are converted into electrical signals and interpreted by your brain. However, when you listen to a recording of your voice played back through speakers, the sound waves have followed a different path. They were recorded by a microphone, converted into electrical signals, stored in a medium (such as a digital file), and then played back through speakers. This recording and playback process can introduce slight changes to the frequency response and acoustics of the sound, leading to a perceived difference in how your voice sounds.
It's important to note that when you hear a recording of your voice, you are hearing it as others hear it, without the additional resonance and bone conduction that you experience when speaking. This can give you a more accurate representation of how your voice sounds to others, which may sound different or unfamiliar to you because you are not accustomed to hearing your voice without the added bone-conducted component.