How do Hammond organ controls change harmonics and timbre?

The Hammond organ achieves its wide variety of timbres through the use of harmonic drawbars located above the keyboard. These controls allow the player to adjust the relative intensities of the instrument's component tones, or harmonics.12

By mixing these harmonics in different proportions, the organ can synthesize complex tones that imitate the sound of other instruments, such as the flute, oboe, or violin. This process works because timbre—the characteristic tone color of a sound—is fundamentally determined by the number of overtones present, their frequencies, and their relative amplitudes. By manipulating the drawbars, the performer effectively alters the waveform of the sound, creating distinct auditory sensations that range from clear and pure to complex and rich.13