 The sounds produced by SCP-628 are not anomalous beyond their origin. Ordinary infrasound, however, has been shown to cause feelings of fear, awe, sorrow, anxiety, and disorientation. Some waves, at or very near 18 Hz, the resonant frequency of the human eye, can also produce simple optical illusions. Since the sound is only audible under ideal conditions, exposed personnel frequently ascribe supernatural causes to these sensations. Level 2 personnel and above may refer to Site-104's database for recordings of original works.