How can we tell if either a piano or violin is playing even when they play the exact same note?

Question

I guess it has to do with wavelengths and physics. But why is it that we can hear the same note in different ways (sung, piano, violin etc.).

Another approach: Let us suppose you knock on two different materials that produce the same tone. Why do they still sound different?

(I don't know how to explain this better)

Answer 1

When you say "the same note" you are meaning the single fundamental frequency of the note.

It is all the "overtones", some of which may be out of phase, that gives richness to the note and allows us to tell a piano from a violin from human voice, etc. Summing all the contributing frequencies with their phases gives the waveform of the sound.

Piano notes are very rich with overtones, and have a particular waveform, whereas the violin and human (sung) voice waveforms are almost pure sinusoidal.

Answer 2

The difference is in the harmonic content of each sound. A piano rod or a violin string generate different harmonic levels when struck, even if their fundamental note is the same. These harmonics are not only of differing amplitudes but also of differing phase wrt the fundamental. The sounds then are very different even though they are the same fundamentally. Viewed on a spectrum analyzer the two signals look very different.

Answer 3

Different instruments play the same notes, but with different harmonics so they sound different.

Not to mention the way different instruments voice a note.  A violin, for example, is a sustained note as long as you draw the bow across it.  A piano is one strike then it dies off.

The harmonics are the main thing though.

Answer 4

i suppose it would be more like pitch and intensity of the sound. A violin would vibrate, it's smaller and is played differently to a piano. (actually both instrument vibrate, but they would do so differently or something lol)

a piano is large and hollow, it involves small hammers hitting the strings. so this could also be due to a different configuration.

Notice that on T.V the adverts are louder than the program?

Answer 5

The pitches may be the same, but the "timbre" is different.