Final answer:
The revolving device, often found in music production and performance, is used to add echo and reverb to vocals and guitars, creating a 'trippy' sound effect by enriching the texture and depth rather than altering pitch or volume.
Step-by-step explanation:
The purpose of a revolving device used for making vocals and guitars sound "trippy" is essentially to add echo and reverb to the vocals and guitars. This kind of auditory effect can make music sound more spacious, giving it an atmospheric quality that can seem psychedelic or dream-like, hence the term "trippy".
In the context of musical instruments such as guitars and wind instruments, the principle of resonance is crucial. Instruments like the guitar have sounding boxes that amplify sound through air resonance, creating overtones and enriching the sound, contributing to the characteristic timbre of the instrument.
A similar principle of sound manipulation is at work with effects devices meant to alter the sound of vocals and guitars, though through electronic means. In the case of rock-and-roll instruments like electric guitars, electromagnetic induction is often used in concert with various pedals and effects devices to create those characteristic, compelling sounds that can range from a gentle chorus to a full-on psychedelic frenzy. The intended effect of these devices is less about altering pitch or increasing volume, and more about enriching the texture and depth of the sound, which includes adding echo and reverb.