Questions
Accuracy, Pro, recordings and privacy, and what to check when something isn't working.
Are the readings absolute SPL?
Close, not exact. Without calibration the absolute level can be several dB off, and the lowest and highest bands are less reliable than the mid-band. You can tighten the level with the 94 dB reference-tone trim or an external measurement mic's .txt / .frd file, both part of Pro.
Can I use it for compliance or workplace noise measurements?
No. SoundMess Lab is a serious listening tool for creative work, not a substitute for a calibrated measurement microphone or a certified sound level meter. It tells you how far each reading can be trusted, see How far to trust it.
Why are some RTA bars faded?
They are the bands where the microphone is less trustworthy, usually the lowest and the highest. The readings are real, just less certain. The info button in the top row lists the ranges.
My device pill still says Baseline after buying Pro.
Device compensation only exists for some models: the iPhone 12 to 15 families, iPhone SE (2nd and 3rd generation), iPad Air (4th generation, Wi‑Fi) and the Wi‑Fi M2 iPad Pro. On other devices, cellular iPads included, the pill stays at Baseline, and an imported external mic file or the reference-tone trim are the ways to calibrate. A trim shows in Settings as Baseline + trim.
Why does RT60 only measure some bands?
Sound is coming out of the iPhone's own speaker, which can't drive the room outside the mids, so SoundMess Lab measures the four bands it can, 500 Hz to 4 kHz. Connect a Bluetooth speaker, a wired speaker or AirPlay to get all eight from 63 Hz to 8 kHz. More in Room RT60.
Is Pro a subscription?
No. SoundMess Lab Pro is a one-time purchase with no auto-renew, and it supports Family Sharing.
How do I restore my purchase on a new device?
Tap any locked feature (the RT60 hourglass, for example) to open SoundMess Lab Pro, then tap Restore purchases, signed in with the same Apple Account. Nothing to restore means no Pro purchase was found on that Apple Account.
What does Pro include?
The spectrogram (the 3D waterfall and the 2D view), finer RTA bands, the advanced FFT settings, RT60, the signal generator, recordings with A/B comparison, export, calibration and the Tactical Violet theme. The full list is in Free & Pro.
How do I compare two measurements?
Open Recordings, tap Compare, choose two RTA or two FFT recordings and tap Compare selected. Or mark one as the baseline and use Compare to baseline from another recording of the same type. See Record and compare.
Why can't I compare these two recordings?
Spectrogram recordings can't be compared yet, and both recordings must be the same type. Two FFT recordings also need the same FFT size and sample rate, because their per-bin levels aren't directly comparable otherwise. RTA recordings always line up.
What can I export?
From the workbench: a PNG of the chart, the band levels or FFT bins as CSV, and a one-page PDF report with your notes. From a recording: the WAV, and for RTA and FFT recordings a time-series CSV. See Export.
Does SoundMess Lab work offline?
Yes. Everything runs on the device, and the app makes no network requests of its own. The only connection is Apple's, for the in-app purchase.
Is it an Audio Unit plug-in?
No. SoundMess Lab is a standalone app for iPhone and iPad. It measures through the microphone, not inside a music app.
Which devices are supported?
iPhone and iPad running iOS or iPadOS 17 and later.
Does anything I measure leave my phone?
No. There is no account, no analytics and no cloud. Audio is only written to disk when you start a recording, and recordings stay in the app until you share them. See the privacy policy.
It says “Microphone access is off”.
Tap Open Settings, turn on the microphone for SoundMess Lab, come back and tap Try again. You can also find it in the Settings app under SoundMess Lab → Microphone.
Measurement stopped after a call or when I plugged something in.
SoundMess Lab resumes on its own when the input is free again. If it shows Measurement paused with Resume measurement, or Audio input unavailable, tap the button on screen (Retry audio input).
I'm not sure which microphone it's using.
Tap the microphone button in the top row. The Audio input card shows the active input and its sample rate.
Readings look 10 to 20 dB off.
Run the reference-tone calibration in Settings → Device with a calibrator or any known 94 dB source.
A recording stopped on its own.
A call or Siri, a change in the input's sample rate, leaving the app, or opening Recordings or RT60 ends the recording. SoundMess Lab keeps what was captured until then, and says why after a call or a sample-rate change. If you ever find an empty recording, email me the steps.
The generator plays through the earpiece instead of the speaker.
Disconnect any Bluetooth audio device and try again.
Related
- How far to trust itPhone microphones are good in the middle and unreliable at the ends. SoundMess Lab shows you which is which.
- Free & ProThe meter and the analysers are free for good. Pro is one purchase for the rest.
- Themes and settingsSix themes, the measurement defaults, calibration, and three Shortcuts.
Still stuck? Write to zhi@nonoaudio.com. Support page