The capability to involuntarily track certain sound signals during the simultaneous presence of noise is essential in human daily life. Previous studies have demonstrated that top-down auditory focused attention can enhance excitatory and inhibitory neural activity, resulting in sharpening of frequency tuning of auditory neurons. In the present study, we investigated bottom-up driven involuntary neural processing of sound signals in noisy environments by means of magnetoencephalography (MEG). We contrasted two sound signal sequencing conditions: 'constant sequencing' vs. 'random sequencing'. Based on a pool of 16 different frequencies, either identical (constant sequencing) or pseudo-randomly chosen (random sequencing) test frequencies were presented blockwise together with band eliminated noises to non-attending subjects. The results demonstrated that the auditory evoked fields elicited in the constant sequencing condition were significantly enhanced compared to the random sequencing condition. However, the enhancement was not significantly different between different band-eliminated noise conditions. Thus, the present study confirms that by constant sound signal sequencing under non-attentive listening the neural activity in human auditory cortex can be enhanced, but not sharpened. Our results indicate that bottom-up driven involuntary neural processing may mainly amplify excitatory neural networks, but may not effectively enhance inhibitory neural circuits.