SynthMaster Oscillators – a Close-up Look

SynthMaster lives up to its name in many ways, but nowhere more so than in the power and flexibility of its oscillators.  We take a close-up look at them in this in-depth examination.


by David Baer, Sept. 2015


If there was an annual award for the developer offering the most synth bang for your buck, I have a feeling that KV331 Audio would be the perennial winner for its SynthMaster software synthesizer, which is routinely available for well under $100 USD.  This is a very deep instrument that easily rivals competitive products costing twice as much.

KV331 quite recently released version 2.7 that contained, among other things, some significant upgrades to the already powerful and flexible oscillators.  One thing SynthMaster is unlikely to win any awards for, however, is the comprehensiveness of the documentation.  The new features have yet to be mentioned in the manual and the old ones are not covered in much depth in the first place.  So a close up look at the oscillators seemed to be a very good idea, and that’s just what we’ll do in what follows.

For those needing an overall introduction to SynthMaster, Rob Mitchell reviewed the instrument (version 2.6) back in 2013.  All of what was presented is still relevant, but now there are more features than ever.  Read that earlier review here:


Oscillator Context

We are truly going to focus on the oscillators here and little else.  But we must start the discussion by showing where they live within the SynthMaster scheme of things.  A preset is comprised of two identical layers (see image right), and in each of these live two identical oscillators in a parallel configuration.  An input modulation port for each oscillator allows for audio-frequency modulation of phase or frequency.  The output of the oscillator can be amplitude modulated at audio frequency rates as well.  The outputs then are passed thru to a filter stage and on to FX, none of which will be subject of discussion here.

The modulators, as such, are not a part of the oscillator but we can hardly ignore them, so we’ll quickly say a few things and move on to the main topic.  There are four modulators, which are themselves fairly capable oscillators.  They can run any waveform that the main oscillators can, which as you will see shortly means that there are a whole lot of options available (including external audio).




The four modulators can be dropped into any of the phase/frequency or amplitude modulation slots in the combinations you see in the menu to the right.  Although the capabilities don’t equal that of a full-blown dedicated FM instrument like FM8 or Rhino, there’s still plenty of FM possibility if that’s your goal.






All about the Basic

But enough of what’s outside the box – let’s go inside the oscillator where things start to get very interesting.  Oscillators operate in one of five modes: Basic, WaveTable, Vector, Additive and AudioIn.  We’ll start with Basic which is probably the mode that will be used most frequently.

In Basic mode, the oscillator produces a single signal based upon a single-cycle waveform or an SFZ-based sample set, any of which can be your own that you can import.  For single-cycle waveforms, there is an extensive list of available waveforms, from basic ones to a vast collection of analog waveforms to exotic waveforms to mayhem.  See the (severely cropped) menu image below to get an idea.  There are over five dozen waveforms in the Moog category alone.

We need to take a brief timeout to discuss terminology.  What we talking about at the moment is using wavetable synthesis for sound production.  These days a lot of people think that term, “wavetable synthesis”, implies that an oscillator must be able to morph between different waveforms.  But that’s not technically correct.  SynthMaster does that kind of multi-waveform morphing as well, and it’s called the Wavetable mode in SynthMaster.  But there are other synths, such as Rapture Pro, that do not do the multi-waveform morphing but do, in fact, implement wavetable synthesis.  So, now that we have that cleared up … 🙂 

The bottom row of the oscillator UI does double duty – it’s effectively tabbed in order to accommodate all the common controls.  As can be seen in the Osc tab, we have a Volume, Pan, Course Tune and Fine Tune controls.  These are common to all the algorithms (we’ll get to algorithms next).  The Remaining two knobs are algorithm-dependent.  By the way, all these knobs are modulation targets.

The Voices tab of the lower row is all about Unison mode, and we might as well talk about that now.  For single-cycle tone production (but not SFZ), up to nine detuned voices can be invoked, and this feature works in the way you’ve seen in many instruments.  What’s interesting about SynthMaster is that a detuned unison operation can be invoked at the higher layer level.  So, what – we don’t just have super-saws, but maybe super-duper-saws?  OK, probably overkill, but it’s there nevertheless.

There are a number of algorithms that can be invoked that are organized into four categories: Spectrum, Bend, Sync and Other. See the composite menu image below to see all the choices.  All the choices do some kind of manipulation of the selected waveform.

Depending upon which is selected, the rightmost two lower-row knobs of the Osc tab provide some kind of control appropriate to the task at hand.  I’m not going to detail these assignments, but I’ll throw in a few examples as we go through the algorithms.

For the Spectrum algorithms, we have six filter options which should need little explanation.  For the Bandpass algorithm, for example, the two algorithm-dependent knobs are used to specify low and high band frequencies.  This set of algorithms should be no mystery.  Like all manipulations in basic mode irrespective of algorithm, as one alters the frequency spectrum for the waveform, the waveform image is updated accordingly – a very nice feature in my estimation.

The next category will be familiar to Massive users.  We have Bend+, Bend- and Bend+/-.  These elongate part of the waveform and squash the other part.  A picture is probably best at this point.  Below we see the Bend+/- algorithm in three bend positions, all-left, middle and all-right.  The middle position is the original, unaltered waveform.

Moving on, next we have the Sync algorithms: No, Half, Cos, Tri and Saw Window.  First of all, the waveform is shortened and duplicated, just as happens in conventional oscillator sync processing.  But then it’s also bounded by a window as described in the algorithm name.  Again, a picture is best.  To the right is a waveform synced and fitted into a saw shaped form using the Saw Window algorithm.

Lastly we have the Other options, Pulse 1, Pulse 2 and Bit Crush.  Pulse 1 and 2 are essentially variants on conventional PWM operation.  Bit Crush is just what it says (although further distortion is certainly available downline in the filters and FX).

There are a few other details before leaving basic-land.  The oscillators can be set to free-running or not, so that when in unison mode, there is or is not a consistent timbre at note-on.  Pitch key-tracking can be altered from the normal, occasionally useful for FX presets or other strange tuning scenarios.  More welcome, to my mind, is the easy-to-invoke pitch deviation control to simulate analog hardware frequency-drift behavior.

You will notice that there are boxes in the second row of UI controls to indicate modulation source for FM and AM.  The modulation source can be selected here just as it can in the layer UI window.  Change it in one place and it’s reflected in the other.


Wavetable (If You Must Use That Term … ) Mode

I have several minor disputes with terminology in the naming of the oscillator modes.  I would definitely have called this mode “Vector”, the name given to the next mode we’ll talk about.  But no matter …  🙂

With Wavetable, we have an array of slots into which different waveforms can be placed.  The position in this table can be selected using the knob labelled Wave Idx, which clearly begs to be a modulation target.  You can use as little as two slots or as many as sixteen.  As one scans through the array, the waveforms seamlessly morph between what’s loaded in the adjacent slots.  In the screen image, you will see that the Wave Idx selection is midway between slots three and four, and the resultant wave reflects that combination of the two wave shapes.

This mode is similar to capabilities found in other synths like Zebra or Serum.  It’s quite straightforward and should hopefully require no additional explanation.


I Have Your Vector, Victor

Vector is similar to the previous mode in that multiple waveforms come into play.  However, here we select four waveforms that are placed in the corners (or on the sides) of a square shape (pictorially it’s a rectangle, but all sides are of equal significance).  All the wave options available in basic mode are candidates here, including SFZ choices.  One can then use the mouse to position the cursor to a location within the bounded control area, and a proportional amount of each waveform will be mixed into the signal based upon that position.  Position movement can, of course, be MIDI learned.  Needless to say, if you happen to have a joystick control at your disposal, this is a great reason to enlist its services.

One thing to notice is that we have little boxes with numbers in them next to each waveform box.  These work as follows.  One can specify an integer, in which case it becomes a frequency multiplier.  Thus with 1, we get the designated pitch, with 2 an octave above, and with 3 an octave and a fifth above (more or less but the frequency of that exact multiple will not be exactly equal to the tempered-scale note equivalent).  Rather than integer multipliers, the other option is to provide an offset in semitones numbering between 1 and 96.  These presumable would be equal to the tempered-scale note at that offset.

Vector mode has two options: 1D and 2D.  We saw what 2D looks like above.  To the right is the 1D configuration.  What’s the difference?  In 1D you will always have at least two waveforms as part of the resultant signal.  With 2D, you can restrict it to a single component waveform by placing the cursor in a corner.






Additive Before Subtractive

SynthMaster is a subtractive synth at heart, so what’s this with an Additive mode?  Well, it’s not precisely an additive synth in the way Harmor or Alchemy … a moment of respectful silence for those in mourning, please … is.  I’d be more inclined to call it “Mashup” mode.  In this mode, we can specify wave selections (again, same ones as in basic mode) in eight slots.  Each has a frequency adjustment, just as in Vector mode, that can be a multiplier or a semitone offset.

So, we can do limited pure additive using sine waves and higher partials.  But other than some simple organ-like sounds, the pure additive is a bit limited compared to real, dedicated additive instruments that can accommodate many dozens of partials.  But this is a very powerful option nonetheless.  Think of it as “Mashup” mode instead and I think you’ll see just how far you can take things in this fashion.  The combined individual sounds can be tuned, panned and mixed in whatever way makes sense.


AudioIn Mode

The final oscillator option is AudioIn.  The sound source is just that: an input audio stream.  I assume that this mode exists, in part, because SynthMaster offers a vocoder feature further down the signal chain in the FX stage of the instrument.  But it can also be used to turn SynthMaster into an FX processor.

The UI for the AudioIn mode shows some controls on the left that clearly are some kind of envelope follower.  On the right, we see an audio trigger for a single MIDI note.  There is zero discussion in the manual for how to use this capability, so I can only speculate that the purpose is to allow SynthMaster to be used as a pure FX plug-in without needing to send it a MIDI stream to open the gate.  Personally, I have little interest in employing SynthMaster in this fashion.  That’s not to imply that the onboard FX options are second rate.  Rather, with the wealth of FX plug-ins available on my DAW, I’m going to reach for something from FabFilter or Melda or Plug & Mix or … you get the idea … when I want to add some FX action to a track.  So, I haven’t been motivated to pursue the AudioIn option.  I’ll just be lazy and … as they say … leave that as an exercise for the reader.  🙂 



I hope you have enjoyed this tour of the new SynthMaster oscillators.  I was well impressed with what SynthMaster could do even before 2.7 came on the scene.  Release 2.7 simply made a great synth even better.  If you have yet to experience this powerhouse, you can find out more here:



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