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