Vibrat-o-matic: producing vocal vibrato using EMS

Vibrato is one of the most popular vocal techniques. Based on the fact that vibrato is caused by periodic pulsation of the cricothyroid and diaphragm muscles, we explore the possibility of reproducing vibrato by actuating these muscles with electrical muscle stimulation. We present "Vibrat-o-matic", a system that enables users to interactively control their vocal vibrato while singing. We test the system on four participants, including two semi-professional singers, under two conditions of the electrode arrangement (stomach and neck). Although the muscles actuated by this system are not exactly the same as those used for natural vibrato, we succeeded in reproducing similar periodic modulation of volume, especially by stimulating the stomach. Moreover, although it is not suitable for training natural vibrato, it is suggested that this system could provide notion of when and where to use vibrato while singing.