ASM Leviasynth

The name Leviasynth suggests an enormous beast of tremendous depth... which isn’t too wide of the mark.

Ashun Sound Machines (ASM) are a brand of the Chinese manufacturers Medeli. This isn’t an unusual arrangement; many companies create brands to address different markets, often to minimise the impact of affordable products on existing, higher‑priced ones. But on this occasion, the concept has been flipped on its head. Known (or rather, not very well known in the West) for their budget arranger keyboards and digital pianos, it’s unlikely that a top‑end synthesizer would have made a significant splash had it carried the Medeli name. I don’t know whether this was the only reason that the ASM brand was established but, either way, it proved to be an astute move because, almost as soon as it was released, the ASM Hydrasynth became a respected and successful instrument. Now, seven years later, I have in front of me the evocatively named ASM Leviasynth. Is this a replacement for the earlier model, or something altogether new? Without wanting to give the game away, it’s the latter, and it’s rather exciting.

The Software

Astute they may be, but the people at ASM/Medeli still have the ability to confuse. When I first read about their eight‑oscillator, 16‑voice polysynth, I wondered how they had implemented half an oscillator per voice. Of course, they meant eight oscillators per voice. Well... sort of. The Leviasynth is, at heart, an extension of an FM synthesizer, so they really meant eight operators per voice. Mind you, all of the operators in an FM synth can act as carriers (ie. sound generators) if the appropriate algorithm is available, which it is. With each operator offering 323 single‑cycle waveforms and a six‑stage DAHDSR amplitude contour generator, you can construct sounds of great complexity on the Leviasynth without invoking any additional facilities.

Of course, this would restrict the Leviasynth to a minuscule fraction of its potential because it offers 144 factory algorithms, plus an editor that allows you to create any other feasible 8‑op algorithms. What’s more, the Leviasynth allows you to morph between up to eight of these as a sound develops, sliding smoothly between them (well, 100 steps per transition, but that’s pretty smooth) or even jumping backward and forward if you apply a suitable modulator. You can even save the sounds created between discrete algorithms! The possibilities are mind‑boggling.

The ridiculous flexibility of the initial sound generation doesn’t stop there because each operator offers seven modes. Yes... individually! In addition to FM, there’s phase modulation synthesis, three models of phase distortion synthesis, a form of width modulation that you can apply to all of the waveforms, plus something called HTE Sync, which is an extension of hard sync.

Once generated, each voice passes through two filter sections. The first comprises a digital filter with 18 modes including two SEM‑inspired, morphing state‑variable filters; a 48dB/octave low‑pass filter; and a morphing formant filter. The second is an analogue 24dB/octave low‑pass filter bank. Both filter sections offer overdrive, are resonant, and will self‑oscillate.

After the audio amplifiers (which offer all of the usual sound‑shaping facilities) the signal reaches four effects sections in series: pre‑FX, Delay, Reverb and post‑FX. The pre‑ and post‑ sections offer the same set of nine effects types, but this can possibly be justified because (for example) the sound of a signal passing through a rotary speaker effect before reverberation is quite different from what you obtain if you apply the reverb first. The effects algorithms are quite suitable for sound design and live work, but I might still be tempted to use external units or software in the studio.

Outside of the signal path, you’ll find five additional six‑stage, loopable, sync’able contour generators, with maximum stage times of 15 minutes! In addition, there are five sync’able LFOs that will oscillate as slowly as 100 seconds per cycle, and can be smooth or quantised to as few as three amplitude steps, as you choose. And, in addition to the preset destinations on the panel, there’s a 32‑slot modulation matrix within which you can apply these, the operator contours, and all manner of internal and external sources to a huge list of possible destinations.

The other main elements in the architecture are a multi‑mode arpeggiator with 64 factory and 64 user‑programmable phrases, and a three‑track sequencer that offers two Note Tracks and a Macro Track with eight lanes for recording your twiddling. These do everything that you might expect, but one facility deserves special mention. This is called Entropy, and it takes the fashionable concept of random playback variations and then force‑feeds it steroids. Currently, this is only available within the arpeggiator but, by the time you read this, it may also be incorporated into the sequencer. I suspect that there are many owners who are going to love it.

Oh yes... and, in addition to the Single mode, there’s also a Multi mode. This is misnamed; it’s a Duo mode...