Final answer:
A person's voice sounds different over the phone because the transmission and reception of frequencies are limited, with higher and lower frequencies often lost, resulting in a compressed sound. The phone's microphone and speaker affect the voice quality and characteristics as well, altering the perception of the voice.
Step-by-step explanation:
Why Hearing Someone's Voice Over the Phone Sounds Different Than in Person:
When person 1 speaks to person 2 over the phone, the sound is created by air being pushed through the lungs, passing the vocal cords that vibrate to modulate the airflow and create sound waves. These sound waves are then converted into electrical signals by the phone's microphone. The quality and range of frequencies that can be transmitted over the phone line are limited compared to what is heard in real life. Most phone systems use a compressed range of frequencies that encompass the most critical elements of speech but leave out the higher and lower frequencies present in a person's natural voice. This is why voices may sound different when heard over the phone. Moreover, psychological factors, like the lack of visual cues and body language in phone communication, may also alter the perception of a voice.
A real-life voice has a complex set of frequency components including harmonics and overtones that give the voice its richness and fullness. Due to technological constraints, a phone system typically transmits sounds between the frequencies of 300 Hz and 3400 Hz. These limitations mean that the subtle nuances and the higher frequencies of a person's voice, which often convey emotion and emphasis, are not transmitted, making the voice sound different. Additionally, the equipment used for transmission and reception adds its own character to the sound, which can further modify the voice one hears.