The glitching sounds featured in glitch tracks usually come from audio recording device or digital electronics malfunctions, such as CD skipping, electric hum, digital or analog distortion, circuit bending, bit-rate reduction, hardware noise, software bugs, computer crashes, vinyl record hiss or scratches, and system errors. Sometimes devices that were already broken are used, and sometimes devices are broken expressly for this purpose. In "Computer Music Journal", composer and writer Kim Cascone classified glitch as a subgenre of electronica and used the term "post-digital" to describe the glitch aesthetic.