[tomstoms]

Interestingly, exact same phenomenon occurs in speech. What is the difference between the sounds /a/ and /o/? Turns out it’s timbre and that our vocal cavities changing form changes the timbre while the vocal chords produce the same fundamental frequency.

[tomstoms]

Further, by producing spectrograms, you can see the dominant harmonics of vowels, they are called formants, and you can learn to differentiate vowels based on comparing spectrograms without hearing the sounds. It’s pretty cool.