The ornamental design for an audiomixer, as shown and described.
FIG. 1 is a perspective view of the front, top and left side of an audio mixer showing my new design;
FIG. 2 is a perspective view of the front, bottom and right side thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom view thereof.
The broken line showing of the audio mixer is included for the purpose of illustrating portions of the audio mixer and forms no part of the claimed design.