Harmonitron vs KP Viewer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Harmonitron
This app creates a rich, swirling harmonic tremolo effect, distinct from standard volume pulsing. It splits sound into low and high bands, modulating them in opposite phases for a lush, phaser-like character. Apply it to various instruments or full mixes as a standalone app or AUv3 effect.
- True harmonic tremolo with anti-phase modulation
- Voice control for morphing between classic and harmonic tremolo
- Split & Tilt for band crossover and balance
- Tube Drive and tone shaping
- Adjustable Rate and LFO Shapes
- Tempo Sync with musical note divisions
- Stereo Spread for auto-pan and width
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Harmonitron is a harmonic tremolo. The rich, swirling amp "vibrato" made famous by early-1960s brownface amplifiers. A normal tremolo just pulses your volume up and down. A harmonic tremolo goes deeper: it splits your sound into a low band and a high band, then sweeps them in OPPOSITE phase. As the lows swell, the highs dip and back again. That contrary motion is what gives Harmonitron its lush, watery, almost phaser-like character that an ordinary tremolo can't reach. Turn the Voice control and the effect morphs smoothly from a classic in-phase tremolo all the way to a full harmonic swirl. Drop it on guitars, keys, synths, pads, drums, or a whole mix. Standalone, or as an Audio Unit (AUv3) effect inside GarageBand, AUM, Logic, and other hosts. THE SOUND • True harmonic tremolo: anti-phase modulation of a low and high band • Voice: morph continuously from classic tremolo to full harmonic swirl • Split & Tilt: place the crossover and balance the two bands • Tube Drive and tone shaping for warmth and grit MOVEMENT • Rate from a slow tide to a fast flutter, shown in BPM • LFO Shape: sine, triangle, square, and ramp with adjustable edge Slope • Tempo Sync that locks to your project and lands on the beat, with musical note divisions from 1/1 to 1/32 (dotted and triplet) • Stereo Spread for auto-pan and rotary-style width HANDS-ON • A living hero orb whose two halves breathe in opposite phase — drag it to set Depth, tap to bypass • Grouped, color-coded controls: Motion, Sync, Harmonic, Stereo, Drive, Output • Factory presets: Brownface, Rotary Swirl, Slow Tide, Sync Chop, Wide Harmonic and more — plus your own saved presets PLUGIN & STANDALONE • Full AUv3 audio-effect support with host presets and parameter automation • Runs on iPhone, iPad, and Mac • Standalone mode with a built-in demo pad, live microphone input, or import a song and export the processed result
KP Viewer
This app provides a clear, at-a-glance display for Kemper Profiler Player users during live performances. It shows current bank, rig name, effect status, morph status, and an automatic tuner, turning older devices into a dedicated stage display.
- Live performance display
- Bank and Rig information
- Rig name display
- Effect status indicators
- Automatic tuner
- Dedicated stage display
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BEFORE PURCHASING KP Viewer requires a Kemper Profiler Player or Profiler Stage and a direct USB connection. • Lightning iPhone or iPad: USB-B-to-Lightning cable • USB-C iPhone or iPad: USB-B-to-USB-C cable Connect the cable, allow the Kemper to power on completely, then open KP Viewer. The app will not function without a compatible Kemper device and cable. KP Viewer gives Kemper Profiler Player users a clear, easy-to-read display for live performance. Connect your iPhone or iPad to your Kemper Player and KP Viewer provides the information you need at a glance, without navigating through menus. KP Viewer displays: • Current Bank and Rig • Rig Name • Effect status for A, B, C, D, X, MOD, DLY, and REV • Morph status • Automatic tuner display The interface is designed to be simple, highly visible, and useful on stage, making an older iPhone or iPad a practical dedicated display for your Kemper Player. KP Viewer is an independent application and is not affiliated with or endorsed by Kemper GmbH.
Screenshots
Verdict
The clearest difference is price: Harmonitron at $2.99 against KP Viewer's $19.99. KP Viewer's advantage is iOS requirement (15.0 vs 17.0). On rating, ratings volume, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Harmonitron costs $2.99 and KP Viewer $19.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for Harmonitron against 5.0 for KP Viewer. Both are backed by a comparable volume of ratings — 2 and 3 respectively.
| Parameter | Harmonitron | KP Viewer |
|---|---|---|
| Price | $2.99 — better | $19.99 |
| Rating | 5.0 (2 ratings) | 5.0 (3 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 2 | 3 — better |
| Update frequency | — | Every 4 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Konstantin Torsten Schutz | DEREK BERNARD |
Customer experience
Harmonitron
KP Viewer
In-app purchases
Harmonitron
No in-app purchases
KP Viewer
No in-app purchases









