TB Lowtone 4+

Bass synthesizer


    • 4.7 • 12 Ratings
    • $9.99



TB Lowtone is an innovative bass synthesizer app and AUv3 / IAA 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 a smart 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.

- 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
- Inter-app audio (IAA) support

What you should know:
- Inter-App Audio (IAA) can only use one instance of this app simultaneously. We recommend to use an AUv3 host to use multiple instances.
- 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.

What’s New

Version 1.1.1

New functionality:
- New multi-note arpeggiator!
- Make VCF response graph interactive for dragging
- Add VCO reset option upon key-on events
- On-screen piano keyboard now supports channel pressure (drag keys up) and slide gestures
- VCO note has new left-right micro edit drag mode for microscopic tuning edits
- FX panel is now draggable
- New option to modulate Punch amount with key-on velocity
- New sustain pedal 'hold' option by double tap on sustain button
- New presets!

- Fixed an issue with legato note handler in certain edge cases
- Fix an issue with modulation indicator lighting up when no modulation was present
- Fixed a keyboard focus issue with program drag and drop operations
- Improved UX for manual entry of slider values
- Make tooltips appear faster with larger font

Ratings and Reviews

4.7 out of 5
12 Ratings

12 Ratings

;$&-%#! ,

Another winner from ToneBoosters

Lowtone has quickly become the monosynth I reach for first when I’m starting a new project. Beautiful lush layered tones. A really excellent noise generator. Great filter section. Super fun and easy gate effect. Tons of great sounding presets serve as easy jumping off points for sound design.

I wish there was round-trip preset compatibility between the iOS and Mac versions of Lowtone in Logic (i.e. I wish the Mac version included an AUv3) but other than that this is just a fantastic instrument.



Anything from toneboosters is hands down amazing. Their apps could fetch more but they are modest in their pricing and deliver the goods straight out the gate! They always put out updates where needed and the look of all the apps is very streamlined and very visually pleasing and you can change the background colors whenever needed. Thanks for your additions to the ever growing auv3 market!

Developer Response ,

Thanks for the feedback!

Superpod wow ,

This is how I wanna bass

Subtle. Fat. Growling. Filters galore. Fun waveforms. This is hard to put down. My neighbors will eventually get used to it.

App Privacy

The developer, ToneBoosters, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

More By This Developer

TB Spectrogram
TB GonioMeter
TB Equalizer
TB Reverb
TB ReelBus
TB Barricade

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