FFT is a high-resolution audio analysis tool for the iPhone and iPod touch. It uses the Fast Fourier Transform to analyze incoming audio, and displays a very detailed graph of amplitude vs. frequency.

Use this app with the built-in iOS device microphone, or upgrade to our iAudioInterface2 or iTestMic for a complete professional solution.

*** Designed for Acoustical Analysis

This application has been designed for acoustics work, and so the bins have been normalized to octaves, to get a display that will show a flat line for pink noise. You can control both the level of graph smoothing and decay time, to get as much or as little detail as you require.

You can also control the dB resolution of the graph, as well as the frequency range that is displayed.

*** Includes Signal Generator

Included in this app is the engine from our Generator app, which is a low-distortion, artifact-free signal generator. The signal generator appears as a heads-up display when you tap the icon, so you can see the graph while you adjust the generator. Generate sine waves, square waves (within limits), white noise, and pink noise, optionally in psuedo-balanced mode. All waveforms are generated in real time using high-precision algorithms.

*** Cursor Readout

Move your finger across the screen to get a cursor to read out exact dB levels and frequencies.

*** Touch-GUI Controls

Use a vertical pinch-open gesture to expand the dB scale.

Use a horizontal pinch-open gesture to expand the frequency scale.

*** Graph Smoothing

Smooth the graph by octave, 1/3, 1/6, 1/12, or 1/24 octave. Adjust the decay time from 0.5 seconds, for a very fast fluid display, to 8 seconds, or use Peak Hold or Average mode. Average mode is a true equal-weighted average, which can run continuously.

*** Peak Tracking

Turn on Peak Tracking to have FFT automatically find a label the frequency of the highest peak on your graph.

*** Tune the Parameters

Set the FFT size from 4096 to 32k points (depending on iOS device) , or select Equal Points Per Octave mode, for high-resolution analysis, even at low frequencies.

*** Calibration

FFT comes calibrated for the typical iPad, iPod touch, or iPhone microphone, and you can adjust the calibration. Microphone compensation files tailored to each iOS device are automatically applied.

*** Save and Recall

When your analysis is complete, you can save the graph image to your photo roll to include in a report, or export the data in an XLS file.

*** Display Multiple Graphs

Show a recalled graph on the screen in a different color.

*** Difference Mode

Use a stored graph as a baseline that is subtracted from the current graph in real time.

*** RTA or FFT?

If you are wondering if you should download this app or our FFT app, check out our website, we have a page devoted to this topic.

*** Other Audio Apps

Also, check out our other great audio and acoustics apps: AudioTools, our premier suite of audio and acoustics analysis apps, SPL, SPL Graph, for recording SPL over time, RTA, RT60, Generator, and Speaker Pop.

What’s New

Version 6.6

-Bug fixes and stability improvements

Ratings and Reviews

5.0 out of 5
1 Rating

1 Rating

madd skillzz ,

Useful Toy

First of all, if you use sound systems, buy this app. Even if you own top shelf gear like I do (2 TEF analyzers, SMARRT, B&K mics with calibrators etc) you will use this A LOT because it is in your pocket. I bought most of the Studio Six apps, and except for RT60 they are pretty handy.

They do NOT take the place of real gear for a bunch or reasons like non pro connectors, poor dynamic range, lack of frequency extension, characteristics of the built-in iPhone mic etc., and the only archiving is saving a pic of the screen, and when you do that it doesn't show what settings you have selected for that measurement. I am hoping that the long promised external mic helps fix a couple of these items.

Enough of the negatives...I use this app several times every day. If I had to give it back I would be bummed. Buy it.

RobertKap ,

An excellent tool

This is an excellent, well designed tool. I have already used it twice to tune systems, and am quite impressed.

If I could suggest a minor improvement, it would be great if the image could be flippable; the mic may be ostensibly omni, but I definitely noticed more accurate results when orienting it towards the speaker, which meant I would have to turn myself around on odd directions in order to get good results.

While this isn't a replacement for full SIMM, Smaart or Spectra-Foo systems, it is certainly capable of analyzing the way speakers behave in a room, and helping a good pair of ears to tune it up.

menicknicknick ,

Great app for the pros who need quick analysis

I am a professional freelance audio engineer and work in different locations every day with different consoles and different clients ranging from presidents to concerts. I have a pretty keen ear for pinpointing a specific frequency but when I am on the run this app is a great help. Usually I use a program called Smaart Live, a $700 RTA program created by EAW, but this app is a definite must for those who would need it, otherwise a fun toy -but a little expensive. The analysis is weighted for the iPhone mic, and it does pick up frequencies down to 30Hz. The decebel meter is fairly accurate.


Andrew Smith
27.2 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, French, German, Japanese, Polish, Simplified Chinese, Swedish

Age Rating
In-App Purchases
  1. Reference Curve Files $9.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

More By This Developer

You May Also Like