It is a sequence of perfectly vertical lines. The lines are uniform in weight/width, but vary in height. They are all vertically aligned along an invisible horizontal center line. The lines vary from shortest to medium to longest, then back down to shortest. This pattern repeats one more time.
Related to Audio Wave Icon
Related icons are the icons with matching tags, as well as all music icons. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors