Coupled oscillators produce complex resonances shared by instruments, voices, and rooms

Evidence

Since masses coupled through springs cannot vibrate independently, the resonance behaviour of such systems is more complex than in the case of the simple mass–spring system of Figure 2.3. … Such modal behaviour is characteristic of simple and complex resonators. As will be explained below, for example the string, the air column, the membrane of a musical instrument, or the human vocal tract show a multitude of mode frequencies. Three-dimensional systems, such as rooms and concert halls, show the same kind of modal behaviour. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 165

Categorization

• DEFINE: Introduces what modal behaviour means for composite systems like strings, air columns, and rooms.
• XREF: Connects to why the author’s later focus on room acoustics and vocal tract acoustics builds on this coupling foundation.