How to Test a Subwoofer

Your sub connected as usual, the subwoofer test and bass test pages, and ideally the decibel meter on your phone at the listening seat for relative comparisons.

Play a 50 Hz tone at low volume. Put your hand on the cone or port to feel it. No output: see subwoofer not working.

Step down 50, 40, 30, 25, 20 Hz. Note where output becomes very weak or you hear only harmonics (a higher “buzz” instead of a deep tone). Small subs often stop around 30–40 Hz; that is normal.

Run a slow sweep from 20 to 200 Hz at moderate volume. Rattles usually come from objects in the room, panels or the sub itself. Hold a hand on suspects to locate them.

Play a tone at the crossover (often 80 Hz) with mains and sub, then flip the phase switch. Keep the setting that is louder at your seat. The polarity test explains why.

Room modes make bass uneven: the same sub can sound boomy in one spot and weak in another. Try the “subwoofer crawl”: put the sub at your seat, crawl around the floor where it might go while playing a sweep, and place it where bass sounds most even.

Match level by ear with pink noise or use a meter for relative readings. Too loud a sub is the most common mistake.

• Subwoofer Test
• Bass Test
• Frequency Sweep