Review of Synthmaster One VST by KV331 Audio

KV331 Audio has introduced Synthmaster One, a wavetable synthesiser built using the same engine as its bigger brother Synthmaster. It is available for Windows and Mac OSx in 32 and 64 bit versions typically priced at $79. A demo version is also available.

Synthmaster One is intuitive and flexible using a one window interface. Essentially it consists of 2 oscillators with associated sub-oscillators, the mixed output of which feeds into two filters which in turn output to one or two envelope modulated amplifiers followed by a series of master effects.

Synthmaster One was created with sound design in mind but it also comes supplied with about 500 presets which can be filtered by categories such as type and author. The presets cover a wide range of arps, sequences, synths, leads, basses and pads. The sound quality is excellent, for instance there are a range of basses from classic analogue to 80s sounds to modern DnB sounds. The pads contain sounds such as strings, evolving textures and darker edged sounds. The arps and sequences also sound great.

The latest version at the time of review is 1.0.4. There have been a number of bug fixes and improvements, it’s good to see that KV331 Audio are responsive to feedback and are providing timely updates. Version 1.0.3 for instance solved compatibility issues with Bitwig 2. This latest version has scaled user interfaces and supports retina screens on Mac OS X. Unfortunately Synthmaster One would not run in my primary DAW, Sensomusic Usine Hollyhock II although KV331 Audio are investigating this issue. The review was carried using MuLab 7.

The stereo oscillators can use standard analogue-style waveforms, single cycle waveforms and wavetables. A number of waveforms are sampled from a range of classic and vintage hardware synths providing a wealth of alternatives to regular analogue shapes.

Wavetables are taken from hardware and are multi-period waves designed with movement in mind. The index control can be used to move the ‘playhead’ backwards and forwards through the wavetable either manually or by modulation, creating effects such as smooth textural shifts or sample and hold style effects. The ability to load custom wavetables gives the potential to create a huge range of sounds.

The raw output of each oscillator can also be shaped using one of 16 algorithms in four categories – spectral, bend, sync and other. As well as waveform displays and algorithm controls, the oscillators also have volume; pan; octave (-3 to +3); semi-tone; fine tune (-64 to 63 cents); unison (upto 16 voices with 5 spread parameters); detune; width; free and detune curve controls.

You can also independently apply drift to each oscillator for that analoge synth feel.

Each oscillator has an associated sub-oscillator which can be used as an audible signal generator or a main oscillator modulation source. There are the standard sine, triangle, square and sawtooth shapes as well as 8 noise types or a wave from Synthmaster’s ‘waveforms’ library. There are also 5 modes of use – sub-oscillator, ring mod, amp mod, phase mod and frequency mod.

There are two zero delay feedback analogue filters with four categories – ladder; diode ladder; state variable; bite. This gives a range of lowpass, highpass. bandpass and bandstop filters. The filters can self-oscillate.


The signal flow between the oscillators and filters can be configured as split, parallel or series. The central display panel gives a visual representation of the chosen mode as a series of blocks, each one containing the respective waveform, frequency response curve or envelope shape of its corresponding oscillator, sub-oscillator, filter or amp envelope.

The effects section acts like a rack holding up to 6 effects with the signal flow running from top to bottom and you can swap and reorder effects as required. These effects sound really good and include 11 in total comprising distortion, Lo-Fi, Ensemble, Phaser, EQ, Vocoder, Delay, Chorus, Tremelo, Reverb and Compressor.

Synthmaster One also has extensive modulation options, up to 12 modulators can be assigned to 24 targets. I especially like how these can be assigned by drag and drop, that’s an excellent feature. They can also be assigned in the modulation matrix. There are several modulation options – constant, alternating, bipolar and unipolar. The modulation amount can be edited and is displayed as a ring around the relevant modulated parameter.

The LFOs are hardwired to the filters but can be available as assignable modulation sources and there are a number of modulation sources available separately for each voice – 4 ADSR envelopes; 2 LFOs; 1 vibrato LFO; midi velocity; bipolar/unipolar/random; alternating.

Arpeggiator / Sequencer
Synthmaster One has a very well featured step sequencer up to 16 steps with each step having its own velocity, length, slide, hold, delta (arpeggiator) and note number (sequence mode). This means that you can create rhythmic arpeggios and polyphonic sequences.

There are a number of classic up/down patterns and various combinations. Arpeggiate mode lets you design your own custom arpeggios by setting successive note increments/decrements defined by midi note input and the range of octaves. Sequence mode allows you to edit, record or import monophonic or polyphonic chord sequences with each step capable of playing up to 4 notes at once. You can record via midi or import midi files.

Background Noise
Synthmaster One can generate one of five background hiss types sampled from hardware synths – Moog sub phatty; Korg MS20; Roland SH101; BOOM SEM; Novation Bass Station. The hiss is summed with filter output then routed to the amp envelope.

Polyphony mode
There are 3 configurations – poly, mono and legato. There’s also 2 glide settings for mono and legato mode, normal and slide which have settings between 3ms and 11s.

Recording quality
Synthmaster One has different rendering quality settings determined by Engine Quality and engine buffer size. Engine quality sets the internal sampling rate – draft (no oversampling); good (2x); better (3x) best (4x). The buffer is the smallest size at which the LFOs, envelopes etc are recalculated – short (16 samples); normal (32 samples); large (64 samples); X large (128 samples).

The Verdict
Synthmaster One is not just a cut down version of its bigger brother Synthmaster. It uses the same engine but has been built from scratch to be an intuitive and easy to use synthesiser. The one screen display is well laid out and easy to use, the central display provides a summary of key parameters such as filter routing and effects.

Starting with the init patch it’s easy to create your own sounds starting with the oscillators, filters, effects then setting modulation parameters. The filters shape the sound really well and you can get some really nice movement in the sound modulating the filter cutoff and resonance settings for instance.

The sound quality is very impressive, Synthmaster One has a very full, deep sound and is capable of producing anything from analogue basses to evolving pads to harsh synth lead sounds.

I’ve really enjoyed using and learning Synthmaster One during this review. I’ve created an album using Synthmaster One as the only sound source processed with various external effects. A lot of the sounds I have programmed myself and have used the odd preset. I have also used drum and percussion loops. The album is embedded below.

I also really like how you can grow with Synthmaster One, It is a synth that you can use straight away using the large number of bundled presets but as you start to create your sounds you start to learn and experiment with features such as loading your own wavetables, optimising filter settings, modulation, LFO drift and hiss settings and you start to get more and more out of it whilst creating your own unique sounds.

When you combine all of these features with excellent value for money Synthmaster One is a very capable synth offering extensive sound creation options suitable for a wide range of styles.