SonoSpec Support
support@sonospec.app
Frequently asked questions
Why does SonoSpec need microphone access?
The microphone is the instrument's input — the app analyzes the live signal and draws its frequency spectrum. Audio is processed entirely on your device and is never recorded, stored, or transmitted. SonoSpec has no network access at all.
What does dBFS mean? Why not dB SPL?
dBFS is decibels relative to digital full scale — 0 dBFS is the loudest signal your phone's audio input can represent. Showing calibrated acoustic loudness (dB SPL) honestly requires a per-device microphone calibration, which SonoSpec doesn't claim yet. Apps that print "dB SPL" without calibration are guessing.
How do I read an exact frequency?
Touch and hold anywhere on the spectrum, split, or waterfall view. An amber cursor appears and the readouts switch to the exact frequency and level under your finger. Release to return to the peak readout. The PEAK readout also uses parabolic interpolation, so a steady tone reads its true frequency, not the nearest FFT bin.
What do the A / C / Z buttons do?
They apply standard frequency weightings, computed per the IEC 61672 formulas: A approximates how human hearing de-emphasizes low frequencies at moderate levels, C is flatter and keeps more bass, Z is unweighted (flat).
What does the FFT size setting change?
Frequency resolution versus response time. Larger FFTs (16,384) resolve close-together tones — 2.9 Hz per bin at 48 kHz — but update more slowly; smaller FFTs react faster with coarser resolution. 8,192 is a good default.
Why does the waterfall stop when I switch apps?
SonoSpec releases the microphone whenever it leaves the foreground — it never listens in the background. Analysis resumes when you return.
Which devices are supported?
iPhone (iOS) and Android phones. An external USB audio interface on Android is used automatically when connected — all of its channels are mixed for analysis.
How do I use the signal generator?
Open the gear menu → Signal generator, pick pink noise, a sine, a log sweep or a warble tone, set the level, and press play. For real measurements, feed the system under test by cable or USB — the phone speaker is not a flat source. The mic keeps analyzing while the generator plays.
What is a target curve?
A reference shape (flat, a −3 dB/oct tilt, or a bass-lifted car curve) drawn as a dashed line over the live spectrum. It auto-fits its position to your measurement, so it is always a relative shape — never a calibrated-level claim. Turn it on in Settings.
How do snapshots and exports work?
The camera button freezes the current spectrum with all its settings. From the gear menu → Snapshots you can recall any snapshot as a ghost overlay for before/after comparison, or share it as an image or CSV. Exports carry a metadata header (FFT size, window, weighting) so the data stays interpretable.
Where is the user manual?
The full Field Guide is at sonospec.app/manual.