Ashun Sound Machines Hydrasynth Review

It might have just been the most anticipated synthesizer of recent years, in a marketplace that's saturated with clones, copies and other lack lustre machines, the Ashun Sound Machines Hydrasynth brings a fresh new vocabulary of synth tones, modulation capabilities and tonal complexity to the game, from a brand new company who right out of the gate, have seemingly brought everything to table and delivered what I personally consider to be one of the finest polysynths ever...really, seriously. In September 2019 at Knobcon Chicago, ASM a subsidiary of very well established Chinese keyboard and instrument manufacturer announced their very first instrument, the Hydrasynth: an eight voice polyphonic digital wave morphing synthesizer with polyphonic aftertouch, a highly configurable sound engine, lush effects and so much more. Ashun Sound Machines Keyboard Available as both a 49-note keyboard (£1299 at time of writing this review) and a module (£799 at time of writing this review), the Hydrasynth not only delivered some fresh, forward thinking features, but at a really incredible price point too. Prior to the UK release I'd been very lucky over the last few months to get hands on with both variations a handful of times and at each opportunity the synth would leave me wanting to play with it more, my appetite had to be satiated so I took the plunge and bought a module from the first UK shipment, and after using it A LOT for a week and really really digging into it, I think I can effectively and convincingly pass judgement on this somewhat complex machine and give it a full review.

So what's a Hydrasynth do then, what is what is what...!?

Good question, as previously mentioned the Hydrasynth is an 8 voice polyphonic synthesizer, the keyboard and module share the exact same sound generating capabilities, but the module forgoes the (obvious) keyboard arrangement, loses the ribbon controller and also lacks a couple of hands on controls, but this isn't a major issue as all aspects of the synthesis architecture are completely accessible using the module select section. The module includes a cluster of RGB backlit pads, which serve as the note input, feature the aforementioned polyphonic aftertouch and can be configured Ableton Push style to quantize to a range of scales aaaand can be laid out in variety of ways to suit your workflow and level of musical capabilities. Me having a guitar background found that the fretboard layout made the most sense to my tiny brain, letting me quickly arrange chords and phrases straight away, but you have a myriad of other options that might fit exactly what you need. So whether you're interested in a module or a keyboard, you'll get access to the same array of mind bending capabilities, but you might just lose out on the wicked mega cool ribbon controller and a couple of knobs. It's also worth mentioning that the keyboard model includes a very interesting quantising option too; you can force the keyboard to run to a set scale and root note of your choice which also passes out to the MIDI outputs, meaning even the most novice of keyboard players can play convincingly and control their other MIDI equipped gear too! I'll prefix the remainder of this review by stating that I don't think there's quite anything else on the market that has been as well implemented and thought through as this machine, it gives a tonne of subtle nods to a more modular workflow with lashings of touch and assign modulation, looping stepped LFO's (Turing Machine style), macro controllers and really does throw everything in, without become cheesy, cliche or overbearing. There's zero menu diving to get to what you want, in fact the only time I've got into the menus was to set my MIDI channel and even that was super simple. The crisp OLED display serves as a scope for the final output and also your main navigation menu and the second contextual display serves as your one stop shop for controlling this insanely deep machine, and the way it's been introduced here means the Hydrasynth can spoil you with features, but you can grasp what you're doing. So what does it do then? Well, ASM have been quite cautious to call this a Wavetable synth probably because that infers a likeness to synths like the Waldorf Microwave XT (etc.) which have access to many thousands of individual single cycle waveforms, which by proxy the Hydra doesn't...but let's call it what it is, the Hydrasynth for all intents and purposes is a wavetable synth, but the way in which they've chosen to implement their wave morphing (wavetables!?) is really quite unique. Oscillator 1&2 share the same architecture and can be configured as singe or wavescan. In single mode they will play a single cycle waveform, of which there's hundreds (219) including your standard foray of analogue waveforms, plus a overwhelming amount of other more complex waves, which are all arranged to form banks of harmonically related content. In the wavescan mode, you can create a custom wavetable of between 2 and 8 waveforms, which you can select manually or using the quite ingenious random button, you can randomise the choices...or using the shift button, you can move the waves in series to create a group of harmonically relevant waves for smoother, predictable results. The resulting custom wavetables allow for smooth interpolation through the scanning, which can be controlled by the very intelligent and wide array of modulation sources on hand, allowing for slow subtle glides, to more aggressive biting tones depending on what you modulate it with. The oscillator section is really designed to be messed with, for example by making a wavetable on VCO 1 that comprises of 5 slices and a wavetable on VCO 2 thats made of 3 slices, you can easily get a rich, complex tone that evolves, moves and gives you an infinitely vast array of textural source material to work with. It really is quite staggering how much you can get out of the synth just from the oscillator section. VCO 3 features the same selection of waves as VCO 1 and 2, but forgoes the wavescan capabilities, which makes it perfect for use as a sub oscillator, a modulation source or a as a droning oscillator since you have variable key tracking for all of the oscillators, letting you crudely obtain some microtonal action if equal temperament just isn't your jam.

The "X Gene" AKA. Mutants and the filterz.

The oscillators 1 and 2 also feature two of these thingies called mutants, or mutators, which is where you find your options of linear FM with some exciting features (yes, multi-op FM is possible!), oscillator sync, wavestack (imagine a supersaw of ANY waveform) and a few flavours of PWM, the most interesting of which is the PWM-ASM, which gives you the ability to pick 8 points per waveform, where PWM would take place, the resulting tone resembles wavefolding more than traditional PWM...but the entire mutant section rather is brilliant to say the very least and sparkes up inspiration at all turns. It's also worth mentioning that mutants can feed into one another, creating a myriad of cascading, complex tones. As with all other aspects of the synth, the mutators can be modulated by the LFO's or the envelopes or pretty much anything else and combined with the complexity of the oscillators, you can easily get lost for hours and hours just feeling out for sounds and effects. So the filters definitely deserve a good amount of explanation too, well there's two of them, one state variable and one morphing filter which can be internally wired in series of parallel. Filter one can serve as one of eleven filter models, which were modelled using an AI algorithm and range from your average 24db low pass, through to more complex and articulate modes like MS20 low pass, through to a very convincing emulation of a vactrol low pass gate. Filter 2 is unique as it can be freely morphed in the vein of a SEM filter, between low pass, band pass and high pass, which is great for dialling out low end rumble is busier patches...even on the module where there's less controls on hand, you can simply flick between each filter and dial in the desired cut off, resonance and the drive or morph (model dependant). Each filter model is very distinct, each with their own resonance characteristics. There's even some filter models that have gain compensated modes where low end isn't lost in high resonance settings, like you might experience with say a 24db ladder. Whilst the filters are digital, I am yet to experience any stepping and in my extensive sawtooth sweep tests I am yet to find a model I didn't like the sound of, the 12db so far is my firm favorite, since 12db filters just ooze that smoothness I crave in a polysynth, but I've also been getting some pretty filthy squeals out of the MS20 models too! They really do sound fan-tastic. One thing to mention here so I don't forget, is that you can feed a specific amount of each oscillator into the filter, meaning you can make subtle adjustments to fine tune your sound, so simply bypass a given oscillator into a given filter...true freedom.

Modulate the modulating modulator for modulation.

It's worth explaining in a bit more detail how the UI works, because it's probably my favourite thing about the Hydrasynth, not knocking the sound by the way, the UI is just THAT good and incredibly intuitive. With a synth that has incredibly complex oscillators and filters, it would be a real let down to have had ASM skimp on the modulation, well they didn't. In fact they threw in no less than 5 envelopes and 5 LFO's...per voice, which might sound like overkill, but the way in which the UI handles modulation means you can make full use of the modulation tools on hand without getting flummoxed or lost. On the front panel you have a module selection section, which follows the signal flow of the synth itself, with neat tie lines to show you some of the internally normalled connections between envelopes, filters and VCAs. When you press a module you want to control, the contextually sensitive encoder and menu selection instantly shows you the range of controllers on hand for that particular "module". So let's pretend you want to set up a modulation connection between VCO 1 and LFO 1, well you simply press LFO 1 and then VCO 1 and the modulation matrix pops up and immediately assigns one to the other, from there you can use the encoders to navigate the options for VCO 1 destinations and apply a depth of the controlling LFO (in this case number 1) and that's it, modulation done. This touch and assign workflow carries throughout the entire synth architecture and since the LFO's and envelopes are super configurable in themselves, you can build complex modulation chains of looping envelopes, one shot LFO's that can form a whole mega series of sound shaping from a single key press. The modulation matrix is super easy to navigate, it has it's own dedicated shortcut key so you don't need to dive into menus and it's just so easy to see exactly what's going on and make changes and build sounds. The LFO's also have some pretty neat functions too, they offer 10 unique waveforms, a free running frequency of 0.02hZ to 150hZ with full tempo sync if desired, but the secret sauce is the 11th secret (not really) LFO wave called step. I mentioned earlier there was a subtle nod to the Music Thing Modular Turing Machine and this is it, tempo syncable stepped LFO's which can run between two and 8 steps, with each step freely configurable. So think of it as looping random which you've designed the levels of random for. In a synth that lacks a sequencer, this is a real joy to tinker with, letting you explore micro-tonal sequencing, of simply dialling in a specific modulation phrase to your destination of choice. And did you notice those mini-jack connectors across the top, yep. There's even connections for controlling and receiving control signals from a modular system, with MOD 1 and MOD 2 inputs being DC coupled so you can send in audio, voltages or pretty much whatever you want, into those inputs to be processed by the can even use them as impulse inputs for the sidechain compressor, which I'll get onto. Any modulation signal can be sent from the synth and vice versa, meaning that complex thing you made on MATHS that can you can't really do on anything else can be put to good use.

Aye up? What about Mixing and FX?

I'll forgo a deep talk about the mixer, it does what it says on the tin it mixes. I jest. The mixer isn't lacking any interesting features, here you can of course mix in each of your three oscillators, but you can also individually pan each oscillator (...yeah mental amiright!?), select the filter routing, apply ring modulation and even filter out some of the artefacts from the noise generator. I mean, they could have just plopped in a three channel mixer and I would have been content. But offering individual panning is a real game changer, especially for cinematic sound design where placing signals carefully in the stereo field can help create a mood. I've actually found it's pretty good for making parts fill out areas of a simple, minimal mix. And then there's the effects, and there are by no means throw away effects. There's actually 4 distinct effects processors, one offer pre effects, a dedicated delay, dedicated reverb and a post effects section. Pre effects and post effects share the same array of possible effects, from chorus, flangers, phasers and rotary speaker simulators, through to surgical EQ's and even a compressor with a SIDECHAIN (YES!!), each is very configurable, modulate-able and sound fantastic, the chorus in particular in this machine has a really rich and varied range of sounds and melds well subtle use of the reverbs. Ah, the reverbs. THE REVERBS. There's four of them, room, hall, plate and my favourite cloud. Each reverb has a wide variety of controls for shaping the sound pre and post reverb, but the best feature for me is that each of them can be frozen with infinite decay, letting you make those huge washes of reverberated goodness with a simple turn of a signal encoder. Real talk. The reverbs are great, like really great. Then there's the delay, with 5 modes from basic delays through to LCR to reverse delay, which can all be set to free run or slaved to BPM if desired. The delays are super clean, very useable and can easily take that simple minimal bleep into otherworldly sonic territory. You can even get them down to super fast timing if a little bit of Karplus Strong is what the doctor ordered. The delay and reverb feed into the post effects, which is where I've found myself fondling the compressor, using the sidechain capabilities taking a feed from my kick drum to give me some of that lovely paddy sidechainy awesomeness.

Strengths and weeknesseses

The Hydrasynth has a lot going for it, if you're into features I defy you to find a synth for this price (£1299 or £799) that does what this can, because there's really isn't anything else ever in the hardware domain that's been so well crafted and thought out, that offers sonic complexity at this level with any kind of immediacy. I mean, I didn't even mention that fact that it has technically infinite presets? Yeah, true - press that random button twice and it'll randomise all of the parameters within musically relevant confines...don't like the randomised sound? Just press that random button twice...and repeat ad infinitum until you get something that you do like. Using the synth is just pure and simple fun, it's inspiring and tickles almost every pleasure centre an instrument can and I get really grumpy when I have to turn it off and go to bed. With all that said there's a few short-coming's I'd mention, which for me personally aren't an issue, but for those who are less initiated in the ways of Hydra might question:
  • It doesn't have a sequencer, although the looping LFO's can make up for this somewhat.
  • It's not multi-timbral, but for a synth with this complexity do you REALLY need it?
  • It doesn't have a VST editor or any form of "total integration" yet...but I hear rumbles this is happening soon.
  • You can't control the LED selector colour per preset (my rather stupid personal gripe)
  • I would have preferred a smaller keyboard like the Elektron Analog Four in place of the pads, but that's simply because I've become accustomed to using said mini keyboard, perhaps I just need to use the pads more!
For the money involved, the amount of music you can get out of this thing and the years of endless sonic exploration on hand, these very minor things are just that. Minor. Because Dominic, Glen and the team at ASM really hit a home run with this synth and whilst many new synths have their time and fade out after a few months, I honestly think we'll be seeing and hearing a lot of Hydrasynth for years to come. It's hyper modern, with some really striking interface choices, infinitely versatile and delivers so much whilst demanding such little time investment to grasp its intricacies. I can't wait to get home and play with it some more.

Pro's - incredible depth, complexity of sound and a wealth of features to keep even the most enthusiastic sound designer busy, it's relatively affordable, is incredibly well built, the module ships with racks ears and it really feels like every aspect has been well thought through and has been well optimised...aaaand it sounds great.

Cons - for some multi timbraility is an oversight, the pads on the module whilst highly useable and configurable might seem a bit alien to some players and the lack of a true sequencer feels like the biggest hole in the Hydras game.

For more information on the ASM Hydrasynth, speak to our synthesizer Specialist Tom Lewis (that's me) or pop into the shop for a demo!