Melthaven vs SpellSynth
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Melthaven
This app provides a note-triggered phase shifter for guitarists, bassists, and synthesizers. It offers organic, rhythmic movement that syncs to your playing, with analog-modeled filters for diverse sonic textures. Enhance loops or create experimental sounds with its input-dependent modulation.
- Note-triggered phase shifting
- Analog-modeled OTA filters
- Responds to guitar and bass transients
- Enhances pre-recorded loops
- Input-dependent synth modulation
- Low-latency engine
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Melthaven is a note-triggered phase shifter built to give guitarists and bassists organic, rhythmic movement that syncs to their playing, rather than a fixed LFO. It's also highly suited for a number of synth basses and sounds with sharp attacks and fast decays. Its analog-modeled OTA filters provide deep resonance and character, ranging from wah-like effects to complex, shifting formant textures or even experimental tones, like bubbling or hard, slappy effects. For bright, harmonically dense signals – such as saturated or overdriven tones and synthetic sounds – the effect range also includes growls and glistening sweeps. FOCUSED ON BASS & GUITARS The effect was specially developed to respond to the frequency response and transient peaks of electric guitars and basses. Every pluck, pop, or pick attack re-triggers the phase sweep, effectively turning your rhythmic timing into the "engine" of the effect. USING LOOPS? BREAK THEM OPEN Add various resonant effects like growls, or vintage bark / quacks "after the fact." This unlocks a level of control usually lost the moment a loop is bounced. Instead of being stuck with locked-in sound design, you can now reshape the envelope of any pre-recorded sample, breathing new life into your loop library. FOR SYNTHS & SOUND DESIGN: INPUT DEPENDENT Soft signals like pads or heavy/layered effects can produce wild, unpredictable responses. While such use is outside the plugin's core design, the smoothing feature can tame these re-triggers, yielding a flow that can feel organic and physical in its instability when operating beyond the plugin’s transient-focused comfort zone. MOVING BEYOND ENVELOPE FILTERS The plugin uses low-latency note detection paired with its own envelope generator and LFO, allowing sculpting and even reshaping each note’s modulation profile or filter envelope. It even detects notes that hide under a consistent signal amplitude when using a traditional envelope follower. BASE FEATURES: - Built around a versatile preset from the Pro version to suit a wide variety of applications - Controls: feedback & panoramic position, attack & hold timings, LFO Rate - Smoothing: from envelope shaping to creating a weighted, fluid response, giving note sequences a sense of physical momentum - Low-latency engine: preserves natural playing feel when used as a real-time effect PRO FEATURES - Requires Pro Edition Upgrade (In‑App Purchase): - Additional envelope parameters, several envelope flavors with pre-mapped control subsets - Pro presets encompassing both strong and milder effects, including the quintessential rubber bass - Enhanced stereo phaser modes & internal stereo re-imaging modulator (for formant-like effects and more) - Vintage-style phaser feedback that can optionally build or ramp with each note onset (non-rampable in the base version) - Instant visual feedback via an audio scope with dual-channel envelopes overlaid on the input waveform TECHNICAL NOTES: - Place before creative effects (unless experimenting). It can be used before or after harmonic processing (saturation, amp sims) depending on your preference - Response may vary on sustained notes with shifting harmonic content - Not optimized for upright bass due to its reliance on sharp signal transients - Note detection involves statistical signal processing and confidence intervals. Weak transients and phantom notes could lead to a loss of output determinism, i.e. sensitivity to changes in certain project settings - While it offers multiple layers of real-time control, Melthaven operates primarily as an automatic effect; for full manual filter manipulation, please refer to RealPhase, a separate app PLEASE NOTE: • The Pro Edition Upgrade is offered as a one‑time In‑App Purchase • An AUv3-compatible host is required to use this app • Suported sampling rates: 44.1, 48, 96 kHz
SpellSynth
This app recreates a classic 1978 spelling toy with four engaging game modes. It allows users to type any word or phrase and hear it spoken aloud using vintage synthesized voices. Explore different speech synthesis eras and even play the keypad with a MIDI keyboard.
- Type and hear any word spoken
- Four game modes (Free Play, Spell, Mystery Word, Say It)
- Three distinct vintage voice characters
- MIDI keyboard support
- Export audio to WAV
- Adjustable gap between words
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SpellSynth is a playable love-letter to the 1978 spelling toy that taught a generation to read — rebuilt for iPhone, iPad, and Mac, in English and French, with five modes, a crunchy VFD display, and three vintage voice characters across two decades of speech-synthesis history. Tap a letter and it speaks. Type ANY word — your name, this week's vocabulary list — and SpellSynth speaks it back. EVERY WORD SPEAKS The 500+ bundled words across 20+ themes use a hand-recorded retro voice. Anything else — a name, your kid's spelling list — falls back to the system engine through your chosen voice, cached so the second tap is instant. • FREE PLAY — type any word, a whole phrase, or a number and hear it spoken. Tap SPACE to build a sentence; it's read back word by word as the VFD cycles. Numbers ("2" becomes "two") and contractions ("don't") speak too. A GAP control tunes the pause between words (50–500 ms), and a RECENT row keeps this session. • SEQ — a 16-step sequencer that speaks a word per step, locked to your tempo. Type four words, get a robot vocal loop. Put a single letter on a step and it says the letter name on the beat instead. FIT stretches each word to fill its step, so words pitch up as the tempo climbs. • SPELL — SpellSynth says a word. You spell it. Three mistakes and you get the answer, then try a new one. HINT reveals a letter when you're stuck. • MYSTERY WORD — the classic hidden-word game. You get the category and first letter free; pick letters until it reveals itself. Six wrong guesses ends it. • SAY IT — listen-and-repeat practice. SpellSynth spells the word letter by letter, then says it whole. REPEAT to hear it again, NEXT for a new one. • SHARE — render any word or phrase to a WAV and send it to Files, AirDrop, or your DAW. EN FRANÇAIS Pick Français in Settings and SpellSynth speaks French: 360+ words, French game screens and an apostrophe key, after the 1981 French edition. The AUv3 speaks French too. THREE VINTAGE VOICES Pick a voice character in Settings. Each one draws from a different era of speech-synthesis history, applied to every word you hear: • 1968 ODYSSEY — calm, deep-baritone monotone with a deliberately slow cadence. Aesthetic homage to the late-60s sci-fi AI voices. • 1978 LPC — the original Speak & Spell character. A 10-pole LPC vocoder driven by the actual TMS5220 chirp ROM, the same speech algorithm Texas Instruments shipped in the toy. Buzzy, granular, unmistakable. • 1986 DECTALK STYLE — fixed-pitch impulse train through formants extracted from your input. Modelled on the Klatt-style synthesis that defined Hawking's iconic computer voice. Deliberate, monotone, emphatically computery. • DEFAULT — clean system speech, no extra processing, for when you just want clear pronunciation. PLAY WITH A MIDI KEYBOARD Connect a USB, Bluetooth, or Network MIDI keyboard and the keypad plays from real keys. MIDI notes 60–85 (C4–C#6) trigger letters A–Z. BUNDLED AUDIO UNIT (AUv3) SpellSynth ships an AUv3 instrument extension, so the same voice engine loads inside GarageBand, AUM, Loopy Pro, Cubasis, Logic Pro for iPad, and any AUv3 host on iPhone or iPad. Type a word and it speaks. Twenty-four parameters cover pitch, speed, bit-crush, sample-rate reduction, filter, envelope, LFO, stutter, the step sequencer, MIDI shaping, language, and voice character. Ten factory presets; all four voices play in your DAW. A serious MIDI surface for performers: sustain pedal (CC 64) for hold-and-release phrasing, Channel Pressure (aftertouch) routable to any parameter, three velocity curves (Soft / Linear / Hard), a pitch-bend range from ±0 to ±12 semitones, and 14 MIDI Learn targets covering every performance knob — bound CCs ride along with the preset. Stutter locks to the host tempo (1/4, 1/8, 1/16), and a Letter Map mode maps A–Z onto MIDI notes 60–85 so you can sequence spelling right in your DAW. Perfect for producers chasing that Kraftwerk / Stereolab / Broadcast sound.
Screenshots
Verdict
The clearest difference is rating: Melthaven at 5.0 against SpellSynth's 3.2. SpellSynth's advantage is in-app purchases (none vs 1) and update cadence (every 6 days vs every 6 weeks). On price, ratings volume, ads 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
Melthaven costs $2.99 and SpellSynth $2.99 up front. Melthaven sells 1 one-off in-app purchase. SpellSynth asks for nothing beyond the download.
Melthaven holds the better App Store score, 5.0 against 3.2. Both are backed by a comparable volume of ratings — 4 and 11 respectively.
Melthaven ships an update every 6 weeks, SpellSynth every 6 days. The most recent releases landed on October 22, 2026 and October 19, 2026 respectively.
| Parameter | Melthaven | SpellSynth |
|---|---|---|
| Price | $2.99 | $2.99 |
| Rating | 5.0 (4 ratings) — better | 3.2 (11 ratings) |
| Positive reviews | — | 50.0% of reviews |
| Number of ratings | 4 | 11 — better |
| Update frequency | Every 6 weeks | Every 6 days — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 23 MB | 112 MB |
| Age rating | 4+ | 4+ |
| Developer | quantovox | Chih Han Lin |
Customer experience
Melthaven
SpellSynth
In-app purchases
Melthaven
- Melthaven Pro$4.99
SpellSynth
No in-app purchases







