Clear answers before you press play.

Yes. Use a tone or sweep and listen for the frequencies that bring out the unusual sound. Start with low phone and speaker volume. You judge what you hear; SignalProof does not automatically identify a damaged part or fix the speaker.

Not for listening for a buzz or checking left/right direction. To compare sound levels, use an external meter or a meter app on a second device. Keep its position, weighting and time settings fixed. SignalProof supplies the sound, not the acoustic reading.

Connect your stereo headphones or external speaker using an output route available to your iPhone, and confirm where the sound is playing before testing. Bluetooth, adapters and speaker processing can affect the result. Stereo left/right output does not individually address a surround system's center or rear speakers; CarPlay support is not promised.

Use the same frequency or noise type, digital level, phone volume, output route, speaker position and distance. When measuring, also keep the meter and room conditions consistent. Write down each intentional change in your test notes.

In version 1.1.0, all signals, presets and playback patterns are free, along with local readings, single-session PDF, rattle marks, 10-second replay and independent retests. The optional one-time SignalProof Pro purchase adds rattle retest comparisons, meter-record comparisons with CSV/PDF export, reading tags, and rattle report packages containing synthesized test audio. Pro is a lifetime unlock, not a subscription. Check the App Store and the app for current prices.

Use Restore Purchases in Settings or on the Pro screen, with the App Store account that purchased the lifetime unlock. Access returns after the purchase is verified. If it does not, contact support with the version and on-screen error.

The current app keeps sessions, notes and presets on your device and requires no account. Reports leave the app when you choose to export or share them. SignalProof generates test sounds; it does not record microphone audio or automatically diagnose the sound. A rattle report can contain synthesized WAV test audio, not a microphone recording. Website analytics have a separate optional consent choice.

No. dBFS controls the digital signal level. Acoustic sound pressure depends on system volume, output hardware, distance and room conditions. Use a separate meter for acoustic readings. SignalProof is not a certified calibrator or a medical hearing test.