Methods and system for testing a voice-enabled device. A signal generator generates a carrier signal having a variable resonant frequency, and a frequency mixer mixes an audible voice command signal with the carrier signal to generate an inaudible amplitude-modulated test signal. An antenna transmits the amplitude-modulated test signal at a variable attack angle to a voice-enabled device. The resonant frequency of the carrier signal and/or the attack angle of the transmitted amplitude-modulated signal are varied and at least one of a sensitive frequency and a sensitive attack angle of the voice-enabled device is identified.