Contradictory scaling behavior in experiments testing the principle of universality may be due to external oscillations.Thus, the effect of damped oscillatory external forces on slip avalanches in slowly deformed solids is simulated using Electronics a mean-field model.Akin to a resonance effect, oscillatory driving forces change the dynamics of avalanches with durations close to the oscillation period.This problem can be avoided by tuning mechanical resonance frequencies away from the range Privacy Booths of the inverse avalanche durations.The results provide critical guidance for experimental tests for universality and a quantitative understanding of avalanche dynamics under a wide range of driving conditions.