SpellSynth vs Raw Byte Audio Machine
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
Raw Byte Audio Machine
This app generates complex musical patterns using a single sawtooth wave and a powerful expression engine. It supports binary and bitwise operations to create rhythms, harmonies, and melodies. Operates as a standalone app or an AUv3 instrument plugin.
- Sawtooth wave synthesis
- Expression engine for sound design
- Binary and bitwise operations
- Rhythm, harmony, and melody generation
- Standalone app
- AUv3 instrument plugin
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The Raw Byte Audio Machine allows the user to operate on a constant sawtooth wave that is calculated against the assigned sample rate and bit-depth. With each sample, the counter "t" increments by 1. Your expression is evaluated and the lowest bits become a PCM audio sample. Expressions allow for binary arithmetic like addition, subtraction, division, and modulo; and bitwise operations like AND/OR/NOT and bit shifting. With these combinations of tools, a single expression can yield tremendous musical results in complex rhythms, harmonies, and melodies, all while operating on a single sawtooth wave. Operates as a standalone app or AUv3 instrument plugin.
Screenshots
Verdict
The clearest difference is review sentiment: Raw Byte Audio Machine at 100% against SpellSynth's 50%. Raw Byte Audio Machine also leads on rating (5.0 vs 3.2) and price ($0.99 vs $2.99). On ratings volume, update cadence, 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
SpellSynth costs $2.99 and Raw Byte Audio Machine $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Raw Byte Audio Machine holds the better App Store score, 5.0 against 3.2. Both are backed by a comparable volume of ratings — 11 and 4 respectively. Written reviews point the same way: 50% of SpellSynth's written reviews are positive against 100% of Raw Byte Audio Machine's.
Both ship on a similar rhythm, roughly every 6 days. The most recent releases landed on October 19, 2026 and October 13, 2026 respectively.
| Parameter | SpellSynth | Raw Byte Audio Machine |
|---|---|---|
| Price | $2.99 | $0.99 — better |
| Rating | 3.2 (11 ratings) | 5.0 (4 ratings) — better |
| Positive reviews | 50.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 11 — better | 4 |
| Update frequency | Every 6 days | Every 6 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 112 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Chih Han Lin | Callback Audio, LLC |
Customer experience
SpellSynth
Raw Byte Audio Machine
In-app purchases
SpellSynth
No in-app purchases
Raw Byte Audio Machine
No in-app purchases






