When the same note is played on a sitar and a flute, the sound produced can be distinguished from each other because of the difference in

When the same musical note is produced on two different instruments, pitch (fundamental frequency) and loudness (overall amplitude) can be the same, yet the perceived difference arises from timbre or “quality.” Timbre is defined as the attribute that lets listeners distinguish sounds with the same pitch and loudness; the sitar and flute are a canonical example of this distinction [1]. Timbre is primarily determined by the harmonic (overtone) spectrum and the dynamic envelope (attack, decay, sustain, release) of the note; stringed/plucked instruments like the sitar produce stronger, richer overtones and distinctive attack/decay patterns (including sympathetic resonance), whereas the flute has fewer prominent harmonics and a smoother envelope, producing a different tone color.

Sources

1. [1] https://www.digitalxplore.org/up_proc/pdf/86-140412247251-55.pdf