An electronic signal X can have its envelope shaped by an electronic control signal Y. For music purposes, signal X can be an electronically generated note and control signal Y can be derived from the musician's voice. The signal shape controller exponentially modifies the control signal Y and multiplies signal X by the exponentially modified control signal Y to form an output signal having an envelope shape XY n . The exponent n has at least one value less than 1 applied to larger values of control signal Y and at least one value greater than 1 applied to lower levels of control signal Y. The controller also preferably includes an attack enhancement circuit to emphasize an attack portion of a control signal and a variable time integrator circuit that integrates the control signal over a short time interval when it is changing rapidly and over a longer time interval when it is changing slowly.