Spectrum Analyzer+ Audio FFT
Find Peak Hz, Hum & Room Modes
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
New: capture 5 seconds of sound and get the strongest frequency, top peaks and energy split on one card. Save it and compare after every change.
Spectrum Analyzer+ Audio FFT shows the live frequency spectrum of any sound your iPhone microphone hears, then lets you capture a 5-second average and read the result: the strongest frequency in Hz, the top components and where the energy sits.
▶ See the spectrum live
• 32 bands from 20 Hz to 20 kHz, computed with a 2048-point FFT
• Four views: Bars with peak hold, Line, Waterfall and Spectrogram
• Peak frequency and peak level update as you listen
• Min / Max traces in the Bars view, tap a bar for a cursor readout, freeze the display to study it
• Adjustable dB range from 30 to 120 dB
▶ Capture 5 seconds, get an answer
Tap Capture 5 s under the graph and hold the sound steady. The app power-averages the spectrum over five seconds and shows a result card:
• Strongest component in Hz, with the musical note and cents in Voice mode
• Up to three top components with their levels
• Share of the detected energy in the low, mid and high part of the selected range
• Strongest band level and the FFT resolution of the measurement
If the sound is too quiet in that range, the card says so instead of inventing a peak.
▶ Compare before and after
Save a capture as a reference (up to 10). Make a change — move a speaker, add treatment, adjust a machine — capture again in the same mode and the card shows the average band-level difference in dB. References can also be overlaid on the live spectrum.
▶ Pick the job
• Voice: 80–4000 Hz, shows the note of the strongest pitch
• Machine: 20–2000 Hz, looks for 50/60 Hz mains hum and its harmonics
• Room: 20–500 Hz, the low end where room modes build up
▶ Export and share
• Export a CSV of the live spectrum or of a 5-second capture
• Share a short text summary of a capture
▶ Extras
• Calibration offset from −20 to +20 dB in 0.5 dB steps to line up with a reference meter
• Pink noise generator, unlocked for 24 hours by watching a short ad
• Interface in 30 languages
▶ Good to know
Levels are relative to the microphone's full scale (dBFS). A phone microphone is not a certified sound level meter, so use the numbers to find frequencies and compare changes, not for compliance measurements. Audio is analysed in memory while you listen and is not saved as a recording.
For musicians checking a tone, home studio and hi-fi owners chasing a boomy note, and anyone tracking down a hum from a fridge, fan or transformer.
Ratings & Reviews
• Capture 5 s: average the spectrum for five seconds and get a result card with the strongest frequency, top components and energy split
• Save a capture as a reference and see the dB difference on the next one
• Start and Capture now sit right under the graph
• Czech, Danish, Finnish, Hebrew and Dutch now show their own language
The developer, Kyu-Hee Jang, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Kyu-Hee Jang
- Size
- 72 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
18+
- 18+
- Contains
Advertising
- Copyright
- © Copyright 2026 Simon Jang. All rights reserved.