This project is a Voice echo module with build-in amplifier and on-board mic.
A project has been designed around Holteks Ht8970 voice echo IC. Project can be used in various audio systems karaoke, toys, animatronics, show, display, exhibitions, and sound equipment’s.
The HT8970 is an echo/surround effect processor. It is designed for various audio systems including karaoke, television, sound equipment’s, etc. The chip consists of a built-in pre-amplifier, VCO or Voltage Control OSC, 20Kb SRAM, A/D and D/A converters as well as delay time control logic.
For more detail: Voice Echo Module With Build-In Amplifier