The basic idea is to slightly overlap a sound with a distinct pitch (a large A/C electric motor, in this case) in different octaves. When played on a keyboard, it gives the illusion of greater and ...

A good way to approach adventurous sound design, therefore, is to purposely stack up several EQs, distortion stages, modulation effects, reverb treatments and other creative effects.

The trace on 3 comes from a sound with a higher frequency than the one on 2. So sounds 2 and 3 are the same volume (amplitude), but 3 has higher pitch (frequency).