I don't believe in witchcraft and Franken Speaker.

The only device invented to recreate lost high frequency from mid frequency harmonics has been invented in the late 60's by Aphex. It is used in recording studios and PA systems using telephone lines in department stores to restore speech intelligibility..

there's subharmonic effects producer.

Harmonizer.

Phaser.When one signal is played back at variable speed against the same signal causing a wave effect and even a cancellation of the sound.

These are usually used for the film industry for special effects.But can be introduced in any music recording for additional punch or enhancement.Ex: Uncle Albert by Paul McCartney.