Demonstrates how FM (frequency modulation) works in synthesizers and keyboards.
About FM Tutorial
FM Tutorial is a music & audio app developed by Frequent Mind.
Download Statistics
FM Tutorial has been downloaded 13 thousand times. In the last 30 days, the app was downloaded 0 times.
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App Information
FM Tutorial is FREE to download. The APK download size is 1.05 MB. The latest version available is 1.7. The last update was on December 5, 2025.
Technical Requirements
FM Tutorial requires Android 2.2+ or higher. The app has a content rating of Everyone. The app has been available on Google Play August 2012.
Description
This app demonstrates how frequency modulation (FM) is used in FM synthesizers to generate sounds. The app plays the FM sound, displays the carrier, modulator and resulting modulated wave as well as the power spectrum and the real and imaginary parts of the spectrum. Sound and display are changed in real-time as the user modifies the following parameters.
Modulation Index (Beta): "Depth" of modulation. The larger this value the more the carrier wave gets "warped" and the more harmonics appear in the spectrum
Carrier Phase (Phi): Shifting the phase of the carrier against the modulator changes the form of the modulated wave and the spectrum.
Carrier and modulator frequencies: These can also be altered.
A Help button (?) for a brief description of the buttons and a more detailed Help in the Menu are available.
The More button (upside down triangle) lets you toggle through the various parameter settings.
Switch additional spectra (real and imaginary) on and off by up and down fling on the screen. Zoom in/out by right/left fling across waves or spectrum (they zoom independently).
FM synthesis explained: In a nutshell, FM synthesis works by changing the frequency of a sound wave (carrier) in accordance with the current value of a second wave, the modulating wave (modulator). If carrier and modulator have the same frequency then the increase and decrease of the carrier wave's frequency takes place within the space of one period of the wave. The result is that the shape of the wave is changed while the period stays the same. If the un-modulated carrier is a sine wave then the modulated will be deformed into something different. This means the spectrum gets additional harmonics, i.e. the sound changes and becomes richer. A similar effect occurs when carrier and modulator frequencies form small integer ratios.
FAQ: Q: Why does the wave change faster/slower when LFO and/or Detune are ON and I toggle speaker ON/OFF (using the button in the app)? A: When the speaker is OFF then the speed with which the display changes can vary between devices, depending on how fast the number crunching is performed.
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Helps but tricky It's tricky to use, but it well explained to me the relationship of the components of an FM. helps me with my communication subject. Thanks by the way.
★★★★☆A Google User· Apr 28, 2013
Gud!! Plz add some thery material to understand the fm properly As lai ppl wil nt understand this
★☆☆☆☆Ian Lary· Oct 28, 2014
This app teaches almost nothing about FM synthesis; I'm very confused at what the Dev meant to achieve here.
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