# Phase Modulator > Phase modulation synthesizer for creating complex audio textures and tones. (iPhone/iPad app by Callback Audio, LLC.) - Source: https://appshunter.io/ios/app/phase-modulator/id6780734729 (this page in markdown: same URL + `.md`) - Developer: [Callback Audio, LLC](https://appshunter.io/developer/1896220942) - Category: Music - Price: $1.99 - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 17.0 · 8 MB - Released: 2026-06-24 - Data updated: 2026-07-31 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/phase-modulator/id6780734729/reviews.md ## What is Phase Modulator? PHASE MODULATOR Phase modulation perturbs the running phase of a carrier oscillator with a modulating signal. Sweeping the phase back and forth generates a series of sidebands above and below the carrier, spaced by the modulator frequency, whose number and strength grow with the Index. This is the same technique behind classic FM synthesis: small index values add a little harmonic shimmer; large values produce dense, clangorous, often inharmonic spectra. The carrier you hear is always an internal oscillator. What changes between modes is where its phase modulation comes from. ------ CONTROLS: CAR FREQ Frequency of the carrier oscillator, 20 Hz to 20 kHz. This is the audible tone in both modes. CAR AMP Level of the carrier oscillator before the Output gain. MOD FREQ Frequency of the internal modulator oscillator, 20 Hz to 20 kHz. Active in Osc + Osc only. The carrier-to-modulator frequency ratio sets the harmonic character: integer ratios give harmonic, pitched tones; non-integer ratios give bells and metallic, inharmonic results. In Input + Osc the modulator comes from your audio instead, so this control is inactive. MOD AMP Level of the modulation source before it reaches the phase. Together with Index it sets how far the carrier phase is pushed; think of it as a trim ahead of the Index multiplier. INDEX Modulation index, 0 to 10. The headline control: peak phase deviation in radians equals Index times the modulation signal. At 0 the carrier passes clean; raising it brings in progressively more sidebands and brightness. OUTPUT Makeup gain after the effect, -24 dB to +36 dB. No limiter follows this stage, so watch your meters when boosting. WAVEFORM Carrier oscillator shape: Sine, Saw, Triangle, or Square. Sine is the classic FM voice. The richer shapes already contain harmonics, so phase modulating them produces denser spectra and reacts more aggressively to Index. MOD WAVE Modulator oscillator shape (Osc + Osc mode only): Sine, Saw, Triangle, or Square. Changes the harmonic character of the modulation itself. In Input + Osc mode the modulation comes from your audio, so this picker is inactive. FOLLOW Input + Osc only. With Follow On (the default) the carrier tracks the amplitude of your incoming audio: it speaks only while signal is present and falls silent when the input does, so the plugin behaves like an effect rather than a constant tone. With Follow Off the carrier runs continuously at its set level regardless of input, which suits drones and sustained textures. In Osc + Osc there is no input to follow, so this control is inactive. ----- MODES: OSC + OSC Both carrier and modulator are internal oscillators, set by Car Freq and Mod Freq. Classic two-operator FM with no input required, good for bells, electric pianos, and metallic drones. INPUT + OSC Your track's audio becomes the modulation source, perturbing the phase of the internal carrier oscillator. Note that what you hear is the carrier shaped by your audio, not the audio itself passed through; the input controls the timbre rather than being processed in place. Mod Freq does not apply in this mode. This is the default mode. ------ A NOTE ON ALIASING Phase modulation can scatter energy well above Nyquist, so the effect runs internally at four times the host sample rate and filters on the way back down. At extreme Index settings with the saw or square carrier some residual aliasing can remain; lower the Index or the carrier frequency if you hear gritty, detuned overtones. ## Key features - Phase modulation synthesis - Internal carrier and modulator oscillators - Audio input as modulation source - Adjustable carrier and modulator frequencies - Modulation index control - Selectable oscillator waveforms - Amplitude tracking of input audio ## Frequently asked questions about Phase Modulator ### What is Phase Modulator? Phase Modulator is a music application that generates complex audio textures by perturbing the phase of a carrier oscillator with a modulating signal. It allows users to create a wide range of sounds, from harmonic shimmer to dense, inharmonic spectra, by adjusting various parameters. ### How does Phase Modulator work? It works by applying phase modulation to a carrier oscillator. This can be done using another internal oscillator or by using your device's audio input as the modulation source. The interaction between the carrier and modulator frequencies and waveforms shapes the resulting sound. ### What are the different modes in Phase Modulator? Phase Modulator has two main modes: 'Osc + Osc', where both the carrier and modulator are internal oscillators, and 'Input + Osc', where your audio input serves as the modulation source for the internal carrier oscillator. ### Can I use my own audio to modulate sounds in Phase Modulator? Yes, the 'Input + Osc' mode allows your track's audio to become the modulation source. The carrier oscillator's phase is perturbed by your incoming audio, shaping the sound based on its amplitude and characteristics. ### What is the price of Phase Modulator? Phase Modulator is available for a one-time purchase of $1.99. ### What devices is Phase Modulator compatible with? Phase Modulator is available for devices with an age rating of 4+ and was last updated on June 24, 2026, suggesting it is designed for modern mobile operating systems. ### How often is Phase Modulator updated? Phase Modulator was released and last updated on June 24, 2026, indicating its current version is 1.0. Further update frequency is not specified in the provided data. ### Does Phase Modulator have ads? The provided data does not indicate the presence of advertisements within Phase Modulator. It is a paid application, suggesting a focus on user experience without ad interruptions. ## Version history (last 1 release) ### 1.0 — 2026-06-24 No release notes. ## More apps by Callback Audio, LLC - [Raw Byte Audio Machine](https://appshunter.io/ios/app/raw-byte-audio-machine/id6766166760) - [Multimode Ladder Filter](https://appshunter.io/ios/app/multimode-ladder-filter/id6769653852) - [Bit Crusher](https://appshunter.io/ios/app/bit-crusher/id6770401698) - [Wavefolder](https://appshunter.io/ios/app/wavefolder/id6772079543) - [Callback Freeverb](https://appshunter.io/ios/app/callback-freeverb/id6775060495) - [Delay Line](https://appshunter.io/ios/app/delay-line/id6776276739) All apps by Callback Audio, LLC: https://appshunter.io/developer/1896220942 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-31.*