TB Lowtone vs QuadroSphere
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
QuadroSphere
This audio plugin allows musicians to sculpt immersive soundscapes by controlling stereo placement and effects across four distinct frequency bands. Create dynamic, atmospheric audio with automated movement and morphing between saved settings.
- 4 configurable frequency bands
- Control stereo separation, level, and pan per band
- Create and morph between 12 snapshots
- Modulation control for automated sweeps
- Per-band effects (Haas, Delay, Reverb, Chorus, Compressor)
- Convert mono to pseudo-stereo
- MIDI CC control
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QuadroSphere is a great tool for bringing an instrument to life by creating a soundscape with a constantly moving sound source. QuadroSphere splits the incoming audio signal into 4 distinct coloured frequency bands using the frequency bar. Each band has an associated coloured sphere allowing you to control the pan, stereo separation and volume level. You can use this plugin as a way to impose subtle control over stereo placement with little or no movement, or go crazy with random automation. Adding effects such as reverb or delay on a specific frequency band can help create a lush atmospheric swirling which surrounds the listener. This is great for musicians trying to create minimalistic ambient or tranquil soundscapes. You can create up to 12 snapshots of the sphere parameters and effect settings, then morph between them at a designated speed (measured in beats). You can also enable continuous randomization mode, and have full control over which spheres and control which parts are automated. You can also use QuadroSphere as a stereo splitter, using the additional outputs to add your own effects to band outputs. Key Features: ○ 4 Configurable frequency bands. ○ Control stereo separation, level and pan for each band. ○ Create up to 12 Snapshots. ○ Morph between various panning, width and frequency band levels. ○ Modulation control for automated sweeps around pan center. ○ Convert MONO signals into a pseudo-stereo image. ○ Per band Haas, Delay, Reverb, Chorus and Compressor. ○ Allows combined and individual per-band audio outputs. ○ Continuous randomized morphing of the stereo field. ○ Built in Preset Manager with drag and drop support. ○ Power and Solo for each band. ○ Controlable morph speeds. ○ Various animated transition modes. ○ Access most options using AU parameters or MIDI CC control.
Screenshots
Verdict
The clearest difference is rating: QuadroSphere at 5.0 against TB Lowtone's 4.4. QuadroSphere also leads on update cadence (every 3 weeks vs every 3 months) and review sentiment (100% vs 85%). TB Lowtone's advantage is price ($9.99 vs $14.99). On ratings volume, 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
TB Lowtone costs $9.99 and QuadroSphere $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.
QuadroSphere holds the better App Store score, 5.0 against 4.4. Both are backed by a comparable volume of ratings — 14 and 10 respectively. Written reviews point the same way: 85% of TB Lowtone's written reviews are positive against 100% of QuadroSphere's.
TB Lowtone ships an update every 3 months, QuadroSphere every 3 weeks. The most recent releases landed on October 12, 2026 and October 20, 2026 respectively.
| Parameter | TB Lowtone | QuadroSphere |
|---|---|---|
| Price | $9.99 — better | $14.99 |
| Rating | 4.4 (14 ratings) | 5.0 (10 ratings) — better |
| Positive reviews | 84.6% of reviews | 100.0% of reviews — better |
| Number of ratings | 14 — better | 10 |
| Update frequency | Every 3 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.0 | 13.0 |
| Further details — not scored | ||
| Size | 13 MB | 18 MB |
| Age rating | 4+ | 4+ |
| Developer | ToneBoosters | 4Pockets.com |
Customer experience
TB Lowtone
QuadroSphere
In-app purchases
TB Lowtone
No in-app purchases
QuadroSphere
No in-app purchases









