On Order. 45 Day Lowest Price - 100% Satisfaction Guarantee. The HV1-DuoBuddy is a simple, stand-alone, all-in-one solution for today's vocalist. Set up your own harmonies and YOU control when they start and stop. Similar to a stomp box effect for guitarists, this 2nd Vocal Generator adds one voice harmony to a melody to give depth to vocals in a live or studio performance.