Lower the volume and test again
Check for blown or damaged speaker cones
Inspect speaker grills for loose parts
Tighten all screws and mounting hardware
Secure any loose wires or connectors
Remove objects touching the speaker cabinet
Check for vibration against walls, shelves, or desks
Place foam pads or isolation feet under the speakers
Move speakers away from resonant surfaces
Test with a different audio source
Test with a different cable
Try a different amplifier or receiver output
Check equalizer settings for excessive bass
Reduce bass, treble, or loudness boost settings
Disable bass boost or sound enhancement features
Verify speaker impedance matches the amplifier
Inspect for torn surrounds or damaged voice coils
Clean debris from the speaker grille and ports
Check port tubes for rattling or loose inserts
Re-seat removable panels or covers
Replace faulty speakers if damage is found
Have the speaker repaired by a technician if needed