There are some people who like to listen there favorite song with big bass and clear sound. Yes! I just help them here.
Learn more:

Top 10 the Best Rockford Fosgate Subwoofers – Guide ...

shallow_mount_12_subwoofer
shallow_8_subwoofe
shallow_mount_subwoofer_vs_regular
best_8_inch_shallow_mount_subwoofer