Recent theories describe perception as an inferential process based on internal predictive models that are adjusted by prediction violations (prediction error). Two modulations of the auditory N1 event-related brain potential component have been interpreted as reduced or enhanced prediction error for predictable sensory input: The sound-related N1 component is attenuated for self-generated sounds compared to the N1 elicited by externally generated sounds (N1 suppression). An omission-related component in the N1 time-range is elicited when the self-generated sounds are occasionally omitted (omission N1). Interestingly, in a previous study we did not observe a modulation of N1 suppression by manipulating the predictability of sound occurrence, but a modulation of omission N1. Here, we wanted to confirm that both N1 suppression and omission N1 are sensitive to the predictability of sound identity, as reported in the literature. We manipulated the predictability of sound identity in a self-generation paradigm in which button presses in one condition always produced the same sound or in another condition produced a sound randomly selected from a large set of sounds, thereby inducing a strong or a weak expectation for a specific sound. Surprisingly, omission N1 was modulated by manipulating the predictability of sound identity but not N1 suppression. This contradicts previous reports, further challenges prediction-related interpretations of the N1 suppression and supports alternative explanations like action-related unspecific suppression of sensory processing.