Subwoofer vibration test – how much bass shakes your floor

How to test bass vibration in your floor

Step 1: Turn the music off. Place your phone flat, screen up, on the floor where you feel the bass most. For a neighbor complaint, use the floor next to the wall or corner you share.
Step 2: Tap Start (on iPhone, tap Allow) and keep still during the 2-second "Hold still" step.
Step 3: Play the song or movie scene that causes the problem, at your usual volume. For a cleaner number, play a steady test tone of about 20 Hz, which sits below the limit on most phones. Your exact limit is in the result details.
Step 4: Let the test run for 30 seconds. Don't walk near the phone, because footsteps show up too.
Step 5: Note the result or tap Save image. Then make one change, such as moving the subwoofer or turning the bass down, and test again at the same volume and spot.
Step 6: Compare the two results. A drop to a lower level means the change helped.

Play the bass. Place your phone flat on the floor where you feel it most.

What your result means

Your result lands on one of four levels. This page uses the people and buildings scale, which is based on peak velocity in millimeters per second (mm/s).

People and buildings scale, peak velocity. Levels: Caltrans Transportation and Construction Vibration Guidance Manual (2020), human response to continuous vibration. Phone readings are a guide, not a certified measurement.
Level	Range (peak velocity)	What to do
Barely noticeable	Under 0.25 mm/s under 0.010 in/s	Hard to feel. If neighbors still complain, they are probably hearing the bass through the air, not feeling it through the floor.
Noticeable	0.25 to 1.0 mm/s 0.010 to 0.039 in/s	People nearby can feel this in a quiet room, mostly at night. Try isolation pads or a lower subwoofer level.
Strong	1.0 to 2.5 mm/s 0.039 to 0.098 in/s	Clearly felt, and likely to bother neighbors. Move the subwoofer away from shared walls and turn the bass down.
Very strong	2.5 mm/s or more 0.098 in/s or more	Loose items will rattle and neighbors will feel it. Turn it down now, then work through the fixes below.

People and buildings scale, peak velocity. Levels: Caltrans Transportation and Construction Vibration Guidance Manual (2020), human response to continuous vibration. Phone readings are a guide, not a certified measurement.

Level

Range (peak velocity)

What to do

Barely noticeable

Under 0.25 mm/s under 0.010 in/s

Hard to feel. If neighbors still complain, they are probably hearing the bass through the air, not feeling it through the floor.

Noticeable

0.25 to 1.0 mm/s 0.010 to 0.039 in/s

People nearby can feel this in a quiet room, mostly at night. Try isolation pads or a lower subwoofer level.

Strong

1.0 to 2.5 mm/s 0.039 to 0.098 in/s

Clearly felt, and likely to bother neighbors. Move the subwoofer away from shared walls and turn the bass down.

Very strong

2.5 mm/s or more 0.098 in/s or more

Loose items will rattle and neighbors will feel it. Turn it down now, then work through the fixes below.

Subwoofer vibration in the floor vs sound in the air

Bass reaches your neighbors in two ways. The subwoofer shakes the floor it stands on, and that shake travels through the building. The sound itself also pushes on walls, floors and ceilings through the air. This test measures the first one: subwoofer vibration in the floor.

If your reading is low but the boom still carries, the problem is mostly sound through the air. A sound level meter tells you more about that. Set it to C-weighting for bass, because the usual A-weighting plays down low notes. Local noise rules are usually written in decibels, not vibration units.

Why most bass is too fast for your phone

Most subwoofers play from about 20 Hz up to around 80 Hz, a common crossover point. Phones deliver about 60 samples per second, so they can measure up to about 30 Hz. That means this test reads the lowest bass directly. Higher bass notes can show up as a false lower frequency. When that happens, the tool says “The main vibration may be faster than your phone can measure,” and the strength number is less reliable.

Two ways to get a fair result:

Use a low test tone. A steady tone of about 20 Hz, from a tone generator app or video, sits below the limit on most phones. Your exact limit is in the result details. Keep the volume moderate and the same every time.
Compare like with like. Same track, same volume, same phone spot. The change between runs matters more than the exact number.

Common causes and fixes

Subwoofer on a wooden floor. A suspended wooden floor works like a drum skin. Put the subwoofer on isolation pads, or on a heavy platform, such as a paving slab on a foam pad.
Subwoofer in a corner or against a shared wall. Corners boost bass. Move the subwoofer out of the corner and away from walls you share. Try a few spots and test each one.
Bass level set too high. Bass boost, loudness settings and a high subwoofer level all add up. Turn the subwoofer level down first, then run your receiver’s room correction if it has one.
Deep movie effects. Some movie soundtracks go below 20 Hz. You barely hear these notes, but they shake floors. If your subwoofer or receiver has a subsonic or rumble filter, turn it on.
Late-night listening. Use your receiver’s night mode, which softens loud peaks, or switch to headphones after a set hour.
Rattles. Loose pictures, vents, glass and shelves buzz with bass and make it seem worse. Find them with a low test tone and pad or tighten them.

For a problem that comes from a neighbor’s system, the house vibration logger records when the shaking happens, so you have times and levels to talk about.

What this tool can’t measure

Loudness. It doesn’t measure sound in decibels. Use a sound level meter for that.
Bass above about 30 Hz directly, which is most bass.
What the neighbor feels on their side, unless they run the test there.
Evidence for a formal dispute. Readings are a good guide, not a certified measurement.

Frequently asked questions

Can loud bass damage my house?

Very unlikely. Caltrans (2020) guidance puts the damage threshold for older homes under continuous vibration at 0.3 in/s (about 7.6 mm/s), far above what home audio makes a floor do. The real risks are rattles and upset neighbors. The construction vibration limits page lists the published numbers.

Do subwoofer isolation pads work?

They can help on wooden floors, by passing less of the subwoofer's shake into the floor. They do nothing for the sound traveling through the air. Test before and after to see what they do in your room.

How do I know if my neighbor feels it?

Ask them to run this test on their floor while you play your usual music. If it reads Noticeable or higher, they can likely feel it in a quiet room. It's also a friendly way to agree on a volume.

Why does it say the bass may be faster than my phone can measure?

Most bass notes are above the roughly 30 Hz your phone can read. Those notes can show up as a false lower frequency, so the tool warns you. Use a low test tone for a clean number, or compare runs that use the same track.

Can I use this as a speaker vibration test?

Only for the deep bass. Regular speakers play mostly above 30 Hz, which a phone's motion sensor can't read. To check a rattling speaker or stand, listen for it, or feel it with your hand while a test tone plays.