ButterSynth vs TB Lowtone
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ButterSynth
This powerful synthesizer app offers a hybrid approach, combining wavetable, FM, and sample-based synthesis. Create unique sounds with a vast sonic range, advanced modulation, and a built-in effects rack. It caters to both experienced sound designers and beginners with extensive presets.
- Hybrid 6-oscillator synthesis (wavetable, FM, sample)
- Built-in wavetable editor
- FM engine with 4 operators
- Sample and Granulator engines
- 32-slot modulation matrix
- Internal FX rack with 16 modules
- Extensive preset library
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ButterSynth is a hybrid 6-oscillator wavetable/FM/sample-based AUV3 and standalone synthesizer with a vast sonic range, from gentle pads to screaming leads and basslines. Mix any combination of wavetable, FM, sample and other synthesis engines for one truly massive sound. For the more advanced users, you'll love using ButterSynth's thoughtfully designed interface, incredibly powerful modulation matrix, fully-featured internal FX rack, factory waveform and sample libraries, and almost limitless scope for fun, experimentation and sound design. For less experienced synth programmers, ButterSynth includes a library of hundreds of ready-to-use presets, sparking your creativity to start making music right away. Headline features include - Mix and match any combination of 6 synthesis engines to either emulate your favourite synths of yester-year or build a synth ready for the future. - Dual-wavetable engines also feature 9 phase modes, wave folding, and deep unison controls modelled on vintage hardware synths. - Built-in wavetable editor gives you the ability to tweak, morph, and hand-draw your own custom wavetables, with each wavetable supporting up to 256 frames. - FM engine offers 4 operators with a selection of 12 modulation paths. Each operator can be loaded with any waveform from the factory or user library, and can also self-modulate via the feedback dial. - Sample and Granulator engines both let you load samples (either imported or from the factory library) and control precisely how they are chopped, triggered and layered. Both also feature the same powerful unison modes available in the WT engine. - Highly configurable 32-slot modulation matrix featuring precise mix/max ranges, self-modulation (via the amount target), plus configurable response curves and layer modes. Simply long-tap any parameter to set it as a Mod destination! - Full suite of versatile control sources which includes: 4x MSEG-style looping curve envelopes, 4x LFOs, 4x step sequencers, X/Y pad with motion recording, 8x Macro dials and a powerful arpeggiator inspired by Kirnu Interactive’s Cream. - The EFX rack lets you build your own insert effects chain using any combination of the 16 built-in FX modules. Modules available at launch include delay, reverb, distortion, chorus, OTT compression etc. Note - FX parameters can also be targeted by the mod matrix, unlocking the possibility to program ‘per voice’ modulated effects. - All presets, wavetables, samples and other settings are stored in the Files app, making bulk import/export, backup and community sharing quick and easy. - All of this is housed in an irresistibly designed 4-tab UI that makes synth programming quick and fun.
TB Lowtone
This app is an innovative bass synthesizer and AUv3 plugin that uses loudness-domain harmonic synthesis for deeper, more consistent bass sounds. It features multiple oscillators, modulation options, and built-in effects, plus an AI randomizer for creating new patches.
- Loudness-domain harmonic synthesis
- 3 analog-simulated oscillators
- Voltage-controlled noise synthesizer
- AI randomizer for patch generation
- Extended LFOs and ADSR envelope
- Pro quality effects (reverb, chorus, delay)
- AUv3 plugin support
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TB Lowtone is an innovative bass synthesizer app and AUv3 plug-in featuring three analog-simulated, voltage-controlled oscillators with a large variety of waveform algorithms, continuous pulse-width modulation (PWM), Frequency Modulation (FM) and oscillator hard sync, complemented by a voltage-controlled noise synthesizer, parameter modulation a re-designed non-linear voltage controlled filter. TB Lowtone is the world's first bass synthesizer featuring loudness-domain harmonic synthesis, creating deeper, more consistent and production-ready bass sounds compared to conventional synthesizers operating in the (linear) amplitude domain. TB Lowtone also features an AI randomizer that generates new patches with a single click, and which learns from the patches you have already created to generate new, personalized patches! Loudness-domain synthesis Loudness perception of tones and harmonics is known to be highly non-linear and intricately frequency and level dependent. Equal loudness contours, or Fletcher-Munson curves demonstrate this drastic effect for sine tones, which is especially relevant for low frequencies. The loudness of a synthesizer bass note, and all its individual harmonics, will therefore depend strongly on what note you play on your synth's keyboard. To overcome the resulting inconsistencies in loudness and timbre, TB Lowtone features innovative, loudness-domain synthesis algorithms that adjust each harmonic individually to compensate for loudness deviations across frequency. Modulation and FX TB Lowtone provides two extended low-frequency oscillators (X-LFOs) featuring a wide range of waveforms. The LFOs can be beat and key synced, with a configurable onset delay and a specific number of cycles to run. In addition, a conventional ADSR envelope with configurable onset delay is provided. To top if all off, a gate editor designed to quickly put together modern production modulation patterns is available as well to modulate a range of VCO, VCN and VCF parameters. Reverb, chorus, and delay effects and a high-quality peak limiter are provided to produce production-ready sounds. Features: - 3 VCOs plus a VCN featuring a wide range of waveform algorithms - All VCOs support hard sync, pulse-width modulation (PWM) and frequency modulation (FM) - Lots of filter types for spectral shaping - 2 LFOs, one extra envelope and a gate editor for parameter modulation - Pro quality effects (reverb, chorus, delay, peak limiter) - Unique loudness domain synthesis algorithms - A smart randomiser that learns from your patches - AUv3 with resizable UI and dozens of color themes to choose from - Preset management including import and export options - Undo, redo, A/B switching What you should know: - Licenses acquired for this platform are not compatible with other platforms. - Audio Unit (AUv3) extensions require an iPad mini 2, iPad 4 or later models.
Screenshots
Verdict
The clearest difference is price: TB Lowtone at $9.99 against ButterSynth's $19.99. TB Lowtone also leads on rating (4.4 vs 4.0) and review sentiment (85% vs 59%). ButterSynth's advantage is ratings volume (63 vs 14). On update cadence, ads, in-app purchases and monetization model 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
ButterSynth costs $19.99 and TB Lowtone $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.
TB Lowtone holds the better App Store score, 4.4 against 4.0. Both are backed by a comparable volume of ratings — 63 and 14 respectively. Written reviews point the same way: 59% of ButterSynth's written reviews are positive against 85% of TB Lowtone's.
ButterSynth ships an update every 2 months, TB Lowtone every 3 months. The most recent releases landed on October 29, 2026 and October 24, 2026 respectively.
| Parameter | ButterSynth | TB Lowtone |
|---|---|---|
| Price | $19.99 | $9.99 — better |
| Rating | 4.0 (63 ratings) | 4.4 (14 ratings) — better |
| Positive reviews | 59.2% of reviews | 84.6% of reviews — better |
| Number of ratings | 63 — better | 14 |
| Update frequency | Every 2 months — better | Every 3 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 14.0 | 13.0 — better |
| Further details — not scored | ||
| Size | 468 MB | 13 MB |
| Age rating | 4+ | 4+ |
| Developer | Arto Vaarala | ToneBoosters |
Customer experience
ButterSynth
TB Lowtone
Bugs and requests
ButterSynth
Reported bugs
39 issues- App crashing with AUM
- Disappears in Cubasis randomly
- Crashes all the time inside Logic
- Changing a patch spikes CPU to 99%
- Crashes on every patch change
Show 34 moreShow fewer
- No audio when rendering or freezing track
- Keyboard doesn't load on iPhone
- iOS18 broke ButterSynth (audio recording issues)
- Failed to load as Auv3
- Crashes as soon as a preset is selected
- Some patches hanging/sounding without input
- CPU spikes to 100% on preset switching
- Audio crackles on preset switching
- Sample module has consistent buzz
- LFOs are extremely simple (no phase offset)
- Square wave LFO is not square (has slew)
- Step sequencer always has glide/slew
- Cannot save custom presets
- No undo function in wave table editor
- AUv3 plugin resets when ButterSynth crashes
- Does not show up as auv3 in Cubasis, AUM, or Audio Evolution
- Crashes regularly even on newest iPad
- Preset changes every time play is pressed
- Not resizing appropriately on smaller screens
- Crashes with unison function in AUM
- White noise on crash with unison
- Sound continues after song stops in GarageBand
- Preset changes on stop, rewind, or play in GarageBand
- Keeps crashing in GarageBand (AUv3)
- Patches in standalone sound different as AUv3
- Crashes when hitting play with arpeggiator/sequencer on iPhone
- No keyboard appears in iPhone standalone mode
- Audio Unit Extension quit error on export
- Lots of crashes in standalone and hosted in AUM
- MIDI not working
- Automation still doesn’t work in Logic Pro
- Random LFO is great for recording sequences
- Preset browser closes each time a new preset is selected
- Works as AUv3 after starting in standalone mode
Requested features
20 requests- MPE popup possible on top of the auv3
- Button to hide built-in keyboard
- Buffer size option
- Additional MIDI mappings (e.g., arpeggiator toggle)
- Sustain pedal support
Show 15 moreShow fewer
- Longer LFO speed for evolving soundscapes
- Alternative skins/color themes
- Pinable preset browser
- Virtual keyboard to remain active while browser is pinned
- Make app take up whole screen (no black borders)
- Master detune
- Parameter lock
- More presets
- Fix square wave LFO to be truly square
- Fix step sequencer glide/slew for discrete steps
- Undo function in wave table editor
- Filter key follow button
- Adjust envelope curves (especially release)
- Easier way to adjust modulation matrix amount
- Phase distortion inclusion
TB Lowtone
Not enough reviews yet to summarise bugs or requests.
In-app purchases
ButterSynth
No in-app purchases
TB Lowtone
No in-app purchases









