Calibrate your iPhone decibel meter — dB Pulse

Know what an offset changes

A calibration offset shifts the reported level so it can better match a reference under the comparison conditions. It does not correct every part of a microphone’s frequency response or extend its usable dynamic range. A match at one tone or level is not evidence of the same match for traffic, machinery and music.

Start by defining what you need: more consistent personal comparisons or a result that must meet a professional standard. The first can benefit from a carefully documented offset. The second needs the required instrument, calibration chain and measurement procedure rather than an app setting alone.

Open the calibration controls

In Settings, choose Microphone Calibration. The page includes Microphone Gear, a Custom Calibration Offset and the applied hardware adjustment. Confirm which microphone is actually supplying input before changing anything. An iPhone microphone and an attached accessory can have different sensitivities and should not be treated as one unchanged setup.

Keep a note of your original setting so you can review an accidental change. Do not move sliders simply to make a quiet room display a familiar internet number. Rooms do not have a guaranteed level, and guessing a target adds apparent precision without a reference.

Compare with a trustworthy meter

For an everyday comparison, place the phone beside a trusted sound level meter in a steady sound field. Keep the microphones close enough to sample comparable sound without blocking either one. Match the weighting and response choices and avoid handling or rubbing the phone during the comparison.

Use a stable broadband sound when possible if the aim is a general environmental comparison. Read both devices after they settle and adjust the offset conservatively. Record the reference instrument, conditions and settings rather than relying on memory. A different source or position may expose limitations that a single match does not reveal.

Understand the reference-tone walkthrough

The app also provides a guided reference-tone workflow based on a 1 kHz, 94 dB reference with a five-second capture. Those are properties expected of the actual reference setup, not values that become true because a phone or website plays a nominal tone.

Do not play a random online 1 kHz tone and assume it is 94 dB at the microphone. Output level depends on the loudspeaker, volume, distance and room. An acoustic calibrator also needs suitable coupling to the microphone; a device designed for an instrument’s microphone does not automatically fit a phone. If you cannot establish a valid reference, leave the result labeled approximate instead of treating the walkthrough as a shortcut to certification.

Recheck after changing the input

Changing earbuds, connecting an external microphone or moving the device into a different acoustic arrangement can make the previous offset less useful. Review the active route and repeat a meaningful reference check. Pro’s automatic microphone-profile matching is convenient for supported routes, but it is not a substitute for validating that particular microphone.

A generic hardware profile is a starting adjustment, not an individual laboratory certificate. Keep your calibration context with any important exported session. If the phone could not be checked, say so plainly in your notes.

Keep claims within the evidence

Calibration may improve consistency around your reference conditions. It does not establish legal-grade accuracy, measure a person’s hearing or prove a safe exposure duration. For a workplace assessment or official complaint, use a suitable calibrated meter and the procedure applicable to that task.

The browser meter has its own calibration control and digital starting reference. An offset in the app is not automatically transferable to the browser, because input routing and processing can differ. Check each measurement system on its own terms.

Sources

• dB Pulse: Decibel Meter on the App Store
• dB Pulse app privacy policy

Phone and browser readings are estimates. For formal decisions, use the specified equipment and procedure; see the accuracy notes.

Try the next check

Noise dose calculator can help with this question. See the matching dB Pulse feature.