Welcome to your second semester of Timbre! I hope you have everything from first semester under your belt! 🙂
Integer Harmonics
Previously, we looked at the harmonic structure of some nice pretty harmonic sounding sounds. That is, sounds that seemed to have a very clear note (tonal center if you will) and a nice even pleasing timbre to them. We did this by looking at platonically ideal waveforms like square waves and sawtooth waves – which are actually common starting points in many synthesizers.
Acoustic instruments are generally pretty harmonic but a little richer sounding. They mostly follow these same integers for their arrangement of harmonics. Although often when I hear instruments from the far east I hear less harmonic, or inharmonic, sounds that sound “clangy” to my ears. I am not at all an expert on these instruments however so I’ll stop there.
White Noise
But I am somewhat of an expert at the piano, which employes stretch tuning, meaning that harmonics are progressively sharper as you go up the piano. This is done to align the fundamentals of higher notes to the slightly sharp harmonics of lower notes. This is also why you will see season stringed musicians tune their instrument to their harmonics.
So inharmonic sound starts on a continuum starting with strech-tuned pianos, extending to clangy sounds, and ending up with atonal sounds and finally random noise. To get that type of sound we start with harmonics that are increasingly not related by whole numbers to the fundamental, extending to atonal sounds such as a snare drum with rattles, through completely random pink or white noise.