Wallrap: Wall Tap Survey

Wallrap listens to your knocks on a wall and estimates, spot by spot, whether the board sounds hollow or solid — the same tap-and-listen technique carpenters use, turned into calibrated, saved measurements. Everything runs on your iPhone or iPad. One purchase, no subscription, no account.

NEW IN 3.0
• Sharper knock analysis: every knock gets a full analysis frame, with pitch inside the knock band, low-frequency energy, strongest frequency and ring-down time. Calibrate on your wall and ring-down becomes a third signal.
• Measured-spacing helper: mark even spacing on the wall (for example every 2 in or 5 cm) and Wallrap turns your trace into solid-center positions and checks the gap against 16" / 24" (400 / 600 mm) framing. Without a measured spacing it tells you only how regularly solid regions repeat — it never guesses inches.
• Rooms and walls over time: save each trace to a room and wall and see that wall's history.
• Wall photos: attach a photo, place movable marker lines (Solid, Edge, Hollow, Avoid, Mark), optionally pre-placed from the trace, and share the marked-up image.
• Backup & restore: one JSON file with your traces, photos and calibration. CSV export now includes positions and ring-down.
• Optional sample survey, clearly marked SAMPLE, to explore before you measure.

WHAT'S INSIDE
• Listen: live hollow / edge / solid readout with confidence and haptics.
• Edge-Lock: knock across a wall and get walked toward the middle of a solid band.
• Trace: a color wall map with solid-center ticks.
• Calibrate: record hollow and solid references on the wall you are working on.
• Repeat Pass: compare two traces of the same marks position by position.
• Mount Check: a checklist and evidence score for a candidate point, with warnings.

PLEASE READ — WHAT SOUND CAN AND CANNOT DO
Wallrap estimates from sound only. It cannot see studs and cannot detect electrical wires, pipes, ducts or metal. A solid reading can also be blocking, a header or something else behind the board. Noise, phone cases, tile, paneling, plaster and masonry reduce accuracy. Avoid drilling above, below or beside outlets and switches, and confirm with a pilot hole or a dedicated detector before drilling or mounting anything.

PRIVATE BY DESIGN
Audio is analyzed live and never recorded or uploaded. Saved traces keep only derived numbers. Photos are chosen with the system picker and stay on the device. No accounts, analytics, ads or tracking.

iPhone and iPad.