Yonac KASPAR Synthesizer Review – 8 Synthesizers In One Single App

The complete oscillator block (3 oscillators, & 1 noise generator) goes than to the filter section that features 14 different filter models. KASPAR includes 14 different filter models from more classic (analog LP, HP,BP…) to more special filters like a formant or comb filter.

The development and implementation of these special filters (formant, comb) was a good decision of Yonac because especially these filters gives sound designers a very wide spectrum of sonic possibilities. It’s always great to have good sounding and modelled analog filters inside virtual instruments but from a sound designer perspective this could be a bit boring because in every virtual analog instrument, you can find today good sounding filters. For this main reason, I find this special filter implementation here great.

The filter envelope curve has been solved very interestingly in KASPAR because musicians can simply move it with the fingers in all directions. Compared to other synths, this envelope is very deep because you have not a traditional ADSR but a ADSHFR  (Attack, Decay, Sustain Hold, Final, Release). A clever feature inside the filter is also the delay function that gives more freedom how to work with the envelope. For even deeper changes, you can choose between an exponential and linear filter env.  On the top right, you have also more classic filter controls like the cutoff, resonance, track and blent.

In summary, the filter section is great done by the Yonac developers because they gives you an amazing amount of high-quality filters which can really form and change your initial sound completely. I would be happy if in the future, it will be possible to add filter drive and FM in this section. Both parameters gives the sound character a far more dirty but interesting sound. Let see what they can implement in future. 

Continue with the amp section inside the synthesis structure. Compared to other virtual analog Synthesizers, this amp envelope is again very exciting. It features a delay amount an a ADSHR (Attack, Decay, Sustain, Hold, Release).

For more curve freedom in this section, the developers implemented here a versatile envelope where you can choose between different curve types. The way how to change the parameters for this, is identical to that in the filter section previously viewed. Touch it with your fingers and draw it in all directions. This is very clever designed because this gives you direct visual feedback how you programmed it.

Next to the LFO page where you have two LFO’s with seven different waveforms and different parameters. An interesting feature here is that you can add pulse width to the LFO waveform. On top, the developers think further and implemented a feature that makes experimental musicians happy. To add more a versatile touch to the LFO’s, you can add for each of the two LFO’s an sample and hold function. Inside the mod section, you can map both LFO’s to several parameters.

Beside two low frequency oscillators, you can find also on a separate page one more envelope with a ADSHR structure for modulating parameters. Compared to the amp envelope, this one doesn’t feature the options to change the curve type. 

Next to the separate envelope, you can find the modulation matrix that features 6 entries. This interface is very smart and intuitive designed.

It’s very easy here to map the modulation to the 21 targets. Cool here, you can also add modulation to the ring mod of oscillator 2 and 3. This gives some more sound design options. With the mod control, you can per example map the mod wheel of your MIDI keyboard to the modulation and control with it the mod amount. Looking back, I would like to see more modulation targets because especially when a Synthesizer is described as Supersynth, it must have more targets in my opinion.

Also I would love to see better support of innovative MIDI controllers which are missing in the initial v.1 of KASPAR. You can use MIDI keyboards like the ROLI and the LinnStrument with this app but it doesn’t exploit the completely potential of this new controllers.

On the next two page, you can find more creative features of KASPAR, the arpeggiator and chord maker. First, you have a full-featured arp with three different operation modes. The live mode is more the classical way how to play a arpeggiator. Press your notes and the arpeggiator will run. To offer here a wide range of arp sounds, the app includes multiple different how to play it. Up, down for more classical arpeggiator sounds but also more creative onces like random or chord more for more deep melodies. Beside more traditional directions, the arp also contains a chord mode where this section play chords back. Not to forget, users can also adjust the melody with all good known parameters like gate, swing, note, note repeat, octave and octave repeat.

The arpeggiator modules in KASPAR goes further and can be used also like a sequencer. In the program mode, you can design your own arp shapes like inside a traditional sequencer. In the program fix mode, you can only play the same notes with all the keys. This is an handy feature if you like to have a fix arpeggiator melody on every key on a specific layer.

On the last page, you can find a chord maker which allows you to create own synth chords. If you want to play only a specific chord for a layer, you can design it here very easy and intuitive.

Important note here: all these features which mention in the last paragraphs, are available in every of the 8 synth layers. There is no difference in the synth structure and all features are the same. Unlike the synthesis structure, the two effects pages are independent and doesn’t exist for every layer. You can route every page independent to the layers inside the mixer but are not available separately in the layers.


  1. This seems to be a very similar model to the Layr synth. Is there a lot of overlap, or do they occupy unique territory?

  2. The interface is in my opinion easier made here than in LayR. Not the biggest fan of the interface of LayR. On the synthesis side, LayR is deeper but KASPAR offers a wide range of waveforms and filters which can be used also for new sounds.

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