Comparison

Harmonitron vs SL Prism

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read full description

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

About

SL Prism

Read full description

SL Prism is a precise, fast, touch-ready equalizer for corrective mixing and creative sound shaping. Create a band directly on the spectrum. Move it to set frequency and gain, then refine Q, filter shape, channel routing, dynamics, threshold, attack, and release. Every enabled response stays visible while you work. Use dynamic EQ to control frequencies only when they become a problem. Enable spectral processing for more focused reactions. Switch between Zero Latency, Natural Phase, and Linear Phase modes to match recording, mixing, and phase-sensitive work. Features: • 24 independent EQ bands • Nine filter types • Dynamic and five-slice spectral processing • Stereo, Left, Right, Mid, and Side routing • External sidechain support in compatible hosts • Realtime input, output, masking, and combined analyzers • EQ Match and resonance suggestions • A/B comparison, Undo, Redo, Auto Gain, Pan, Phase Invert, and Mix • Factory effects including Underwater, Telephone, Airy Vocal, Warm Vintage, and Lo-Fi Radio • AUv3 plugin and standalone app • Scalable interface for iPad Audio is processed locally on the device. Core EQ processing does not upload project audio.

Screenshots

Harmonitron2 screens
SL Prism3 screens

Verdict

The call

The clearest difference is price: Harmonitron at $2.99 against SL Prism's $19.99. SL Prism's advantage is iOS requirement (15.0 vs 17.0). On ads, in-app purchases and device support 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

CostPrice · In-app purchases · Ads · Monetization

Harmonitron costs $2.99 and SL Prism $19.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Scorecard2 real differences · 7 level
Harmonitron versus SL Prism: the parameters behind the verdict, then further details
ParameterHarmonitronSL Prism
Price$2.99 — better$19.99
Rating5.0 (2 ratings) — better—
Number of ratings2 — better—
Update frequency—Every 10 days
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.015.0 — better
Further details — not scored
Size3 MB18 MB
Age rating4+4+
DeveloperKonstantin Torsten SchutzVIACHESLAV ZHILTSOV

In-app purchases

None

Harmonitron

No in-app purchases

None

SL Prism

No in-app purchases

Questions

Is Harmonitron free?
Harmonitron costs $2.99, with no in-app purchases.
Is SL Prism free?
SL Prism costs $19.99, with no in-app purchases.
Do Harmonitron or SL Prism have ads?
Neither Harmonitron nor SL Prism shows ads.

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