Subwoofer test tones: how to test your sub at 30, 40, and 60 Hz

How this is calculated

A useful subwoofer test isn't a sweep - it's discrete tones you hold long enough to walk around the room. Bass wavelengths are long (a 50 Hz wave is about 6.8 meters, or 22 feet), so the difference between a great seat and a null can be several decibels. Walk the room while a 50 Hz tone plays and you'll find the standing-wave peaks and dips your room correction system is fighting. The 30 Hz tone specifically checks excursion and port tuning - if your sub makes mechanical noises or chuffs at 30 Hz but not at 50 Hz, it's running out of linear travel or the port is undersized. The 60 Hz harmonic is also useful because some rooms have their first mode right around there.

Verdict

A minute with three pure sine tones tells you more about your subwoofer setup than an hour of music. Test 30 Hz for clean low-end extension, 50 Hz for the room's main resonance band, and 60 Hz for the harmonic. If you hear mechanical noise, port chuffing, or big dips as you move around the room, those are the problems music won't surface.