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ASM Hydrasynth Keyboard

Digital Wave Morphing Synthesizer with Polyphonic Aftertouch

ASM Hydrasynth Keyboard

A Replicant or a Mutant?…

Seen from the outside, the Hydrasynth, designed and manufactured by the young Chinese company ASM (Ashun Sound Machines), does not seem to be an impressive and exceptional synthesizer: 8 voices of polyphony, monotimbral, and a keyboard "only" of 4 octaves. So nothing that could a priori give desire. But the Hydrasynth hides its play well. ASM has designed the Hydrasynth which seems to combine the best of the emblematic synths, with some innovations. This synth seems to combine the characteristics of some famous synths, with concepts that seem quite unique. The Hydrasynth exists in two forms: the "tabletop expander" version the Hydrasynth Desktop with 24 pads and the keyboard version with 49 keys.

On the Keyboard version of the Hydrasynth, the keyboard is dynamic with polyphonic aftertouch - differentiated touch pressure for each key of the keyboard - and a ribbon controller covering the 4 octaves. It smells like the inspiration given by the famous Yamaha CS80… The return of polyphonic aftertouch on the Hydrasynth is a good thing because the keyboards with it disappeared from the shops at the same time as Ensoniq. This manufacturer implemented it on most of its keyboards (from the SQ-80 thru MR-61 et MR-76 through the VFX and VFXsd). On the Desktop version of Hydrasynth, the pads are sensitive to velocity and also to polyphonic pressure. The Hydrasynth keyboard with "Polypressure", named Polytouch™, was designed by ASM.

The Hydrasynth Keyboard is well finished. The construction inspires confidence. The two 4 mm thick aluminum sides give an impression of solidity. It's a change from wood or plastic sides, which look modern. It reminds me of a Roland Roland Jupiter-Xm, seen from afar souriant. The impression of solidity is also given by its weight of 10kg. The facade is sober. It is made of metal painted black with its orange silkscreen print "Roland Jupiter" to define the sections and white for the dedicated buttons. The lights, displays and other illuminated buttons do not make "Christmas tree" or "rainbow" like some recent synths. Well yes, I talk about it below in the "Light Show"… The screen printed buttons are backlit in white or with a nice amber color more or less bright depending on the context. Buttons with white text do actions and those with orange letters select functions. The amber LFO and ENV buttons can glow more or less brightly depending on the "voltage" generated by the low frequency oscillator or the envelope. That's nice! The layout of the control panel is well structured and invites you to manipulate the numerous potentiometers, encoders and other buttons. The controls are grouped into 7 sections. Numerous knobs, encoders and buttons make it very easy to change the patch while the performance. The 49-note keyboard with its normal size and light touch is topped by a 67 centimeter ribbon, the width of the 4 octaves. The ribbon controller has three modes of operation. It can be a Pitch Bend, a Theremin or a modulator. As for the left side of the keyboard, there are the classic pitch and modulation wheels. These wheels, which have a backlit circular segment on their circumference, are topped with a little stick that is a bit confusing when you are used to a hollow on the wheels. Above these wheels are two octave modifying buttons to decrease or increase the pitch of the keyboard (one octave at a time). To the right of these two [OCTAVE] keys is the one called [CHORD]. This button allows you to play up to 8 notes at a time by activating the [CHORD] button, provided that a chord is created beforehand so that this "one-finger chord" function can be used.

Mini-jack connections are located on the top left above the Arpeggiator section. These are seven 3.5 CV/Gate jacks for connection to the modular world. There are five outputs (Pitch, Gate, Mod 1, Mod 2 and Clock) and two inputs (Mod 1 and Mod 2). In front, under the pitch and modulation wheels - illuminated from the inside - are two headphone jacks associated with a volume knob: one in 6.35 mm and the other in 3.5 mm. Practical. The volume knob adjusts the level for both headphones. At the rear is the stereo output (balanced 6.35 mm TRS jacks), one input for a sustain pedal and another for an expression pedal (both in classic 1/4" jack), MIDI trio on 5-pin DIN, a USB type B connector (like on a printer), and an input for 12 Volt 1 Amp DC power supply. This panel is completed by a rip-proof hook for the power cable, a Kensington notch and the power switch.

The Hydrasynth does not have a large color display, like the Korg Kronos 61, Roland Fantom 6 or Yamaha MODX6, but five monochrome OLED displays including four smaller ones (hidden behind a Plexi® to look unique and larger). The four small displays allow to visualize 8 parameters at the same time, and even more if the PAGE buttons [▲] and/or [▼] are illuminated (highlighted). In this case, one or more other parameters are displayed by pressing them. This central layout reminds me a lot of the Ensoniq VFX. On the latter, when a program is being edited, the display shows a maximum of six parameters, three at the top and three at the bottom, sometimes on two pages. One of these six parameters can be edited by pressing the button next to the displayed parameter. This parameter is then underlined to identify it. Similarly, the "Programming" buttons for the editable functions are located on the right side of the control panel, but not in the form of a mimic diagram like the "Module Select" on the Hydrasynth, but rather in the style of a numeric keypad. Where the Hydrasynth is more pleasant, it is thanks to the 8 smooth encoders with a ring of LEDs, which gives a more practical and fast action compared to the two push buttons "plus" [▲] and "minus" [▼] or the "Data Entry" slider of the VFX. In the center, under the big "Browse" wheel to select a Patch, is a screen that displays part of the patch list, 5 lines. When playing, this screen turns into an oscilloscope and displays the waveform generated by the Hydrasynth. This Oscilloscope function can be deactivated in the "System" menu (Master, page 1, Control Knob 3), in this case the name of the patch is permanently displayed. When an envelope is edited, the 6 DAHDSR segments are represented as a curve, the same applies to the filter and the response curve, the LFOs, etc. For direct controls, 1 pot = 1 function, there is the ARPEGGIATOR on the left with 8 buttons including 4 potentiometers and 4 switches with 4 or 8 positions (Tempo, Ratchet, Chance, Gate, Mode, Octave, Division, Swing) and the FILTER CONTROLS part on the top right with these 5 potentiometers (Cutoff, Resonance, Drive, Morph, Env1, LFO1) and two switch buttons to activate filters 1 and 2. The two filters can be used in series, with filter 1 feeding filter 2, or used in parallel, where each filter has a direct path to the output.

The Hydrasynth is an eight-voice synthesizer with three oscillators per voice. Oscillators 1 and 2 can operate in "WaveScan" mode or single mode; oscillator 3 is always in single mode. In "Single" mode, the oscillator can be set to any of the 219 predefined waveforms of the Hydrasynth. It is not possible to add your own waveforms, neither by USB nor by SD card reader. The first five waveforms are simple and classic "analog" waveforms: sine, triangle, sawtooth up, sawtooth down, square. The other waves are more or less complex samples. This can be seen on the screen of the "Main Systems" section in Oscilloscope mode. They are organized in small groups of similar shapes, with more or less evocative names: Pulse, Horizon, Synclav, Vokz, Flux, Resyn, Harmon, etc. The "WaveScan" mode allows you to select up to eight waveforms from the list of 219 shapes. The WaveScan smoothly morphs (crossfades) between the selected waveforms. WaveScan gradually transforms the generated waveform between the positions in the wave list, using an LFO or other source via the modulation matrix. This produces progressive timbres like the Prophet VS, Ensoniq VFX or Korg Wavestation.

Oscillators 1 and 2 can each use two mutators (MUTANT). Mutants are processes that allow modifications, transformations, of the shape of the audio signal. Depending on the selected mode, the output of one of the mutants in a pair can be fed into the next Mutant and/or any other Mutant, including itself. In some modes, Mutants are dedicated to the oscillators with which they are paired. Each Mutant allows to choose among 8 processes: FM-Lin (FM with 2 operators), Wavestack (5 audio copies), Hard Sync (synchronization on one of the 3 oscillos), PW-Orig (pulse width modulation), PW-Squeez (softer PWM), PW-ASM (PWM on 8 sections of the wave), Harmonic (accentuated harmonics), PhazDiff (summing phase shifter). Each Mutant process brings its color to the outgoing timbre. The screen of the "Main Systems" section in Oscilloscope mode allows to "see" the modification of the wave.

The Ring-Noise module contains two additional sound sources that can be mixed with the oscillators to produce even more diversified sounds. Ring Modulation (Ring Mod or RM) takes two audio signals and generates a sound based on the sum and difference of their frequency content. Depending on the source, the result can be pure sinusoid-like, or it can be electric, "trash", or even erratic. The noise generator produces random and simultaneous frequencies over a wide range. The different colors represent specific frequency ranges, spectral power density (white, pink, brown, red, blue, purple, gray noise).

The three oscillators and the Ring-Noise enters a MIXER section. To set the relative levels of the sources press the [MIXER] key. The OLED displays will show the levels. In the top row are the levels for oscillators 1 to 3, while the levels for the Ring-Modulator and the Noise module are on the bottom row. To change the levels, use the appropriate encoder for each element and press the [SHIFT] key with the encoder to fine-tune the level setting. The mix then enters the FILTER section consisting of two filters (in series or parallel).

The filters can be controlled by the first envelope (ENV1) and/or the first low frequency oscillator (LFO1). This parameter sets the filter between its different states, with a low-pass filter at one extreme, a high-pass filter at the other, and a band-pass or notch filter in the middle. The types of filters are very varied. They are multimode, resonant, 2- or 4-pole, and voice formants (vowels). Along the way, there are hundreds of intermediate parameters. As the value changes, the graph on the large OLED shows the character of the filter.

As the signal exits these filters, it then goes into an amplifier. This can be controlled by the second envelope (ENV2) and/or the second low frequency oscillator (LFO2). The Hydrasynth has 5 envelopes with 6 DAHDSR segments (delay, attack, decay, sustain, hold, release) that can loop, 5 LFOs (noise, sample and hold, sawtooth up, sawtooth down, sinusoidal, square, triangle, clocked, delay) that can be in one-shot mode. What a lot of fun…

Hydrasynth has effects to sublimate the already rich sound. Four independent effects modules are available, two of which provide spacialization effects with delay and reverb, while the other two are modulation and dynamic effects: Chorus, Flanger, Rotary, Phaser, Lo-Fi, Tremolo, EQ, Compressor, Distort. The only difference between these two FX modules is that one precedes the Delay and Reverb and the other follows them. They serve different purposes due to their placement in the signal path, so they will often have different settings.

The [MOD MATRIX] knob provides access to a virtual patchbay that has a potential of 32 modulation routings per patch. These routes are in addition to the macros, although they can be controlled by them (and vice versa). Potential sources for the modulation routes include LFOs, envelopes, velocity, expression pedal, one of the CV inputs (Mod1 and Mod2) and any MIDI CC#, including the RIBBON. But the way the ribbon interacts with the Mod Matrix deserves special attention here. The variation on the ribbon can be relative or absolute (see page 70). The destination of the source can be almost any parameter of the Hydrasynth, including any Mod Matrix route. Additional destinations include the macro, MOD1 and MOD2, CV output and any MIDI CC#. A separate chapter describes how to use The Mod Matrix (see page 78).

The Hydrasynth has five BANKS of 128 patches. This makes it possible to store a total of 640 programs. The Hydrasynth, in V1.4, is delivered with factory programs in banks A, B and C. Banks D and E are empty; it's up to me to fill them. The factory programs are not in ROM. I can very well modify them or save another program in these locations. The large "Patch Knob" encoder above the large display allows you to select a Patch. To change the Patch number increment or decrement from 10 to 10, hold down the [SHIFT] button and press the [◄] or [►] button. To change the bank, hold down the [SHIFT] button and turn the Patch Knob encoder. By pressing the [BROWSE] button, the "Control knob" encoders can be used to change the order of the patches. There are three different sorting/displaying orders of the patches: by number, by name or by category. There is a Patch protection parameter in the system configuration that is enabled by default. For example, the first time I pressed the [SAVE] button, the left screen displayed the message "Protection is On! The protection must be disabled before a patch can be saved (System Menu, Master, page 1, Control Knob 4).

ASM had the good idea to create a table of 32 FAVORITE patches. This avoids reorganizing the banks of the Hydrasynth. This makes them easily accessible for quick selection. There are four groups of favorites, each containing eight patches. It is by eight because the four OLED screens only display 8 patches at a time. You can save the same patch in several locations in these favorites, for example if you need this patch more than once during a performance, such as a concert. To save a Patch in the favorites, refer to page 16 of the V1.5 manual. My Favorite Patches can be accessed from any other page. To display them, I press [SHIFT] and [BROWSE] to display my Favorites. I use the "Down" [▼] and "Up" [▲] keys to display one of the four favorite groups. Then I press one of the [Control buttons] next to the name on the OLED display to select a Patch from the group of 8 displayed programs.

The ARPEGGIATOR allows "arpeggiations" of standard notes (Up, Down, Order, Random, etc.), but also has built-in sentence arpeggiators (64 sentences). Parameters such as SWING, RATCHET and CHANCE will generate other rhythmic patterns with a certain randomness to add life and spontaneity to a sequence that is a bit too mechanical and repetitive. Most of the arpeggiator parameters can also be modulated. There are avenues to explore regarding the use of LFOs, envelopes, polyphonic aftertouch or the ribbon controller to modify arpeggios in real time. To enter ARP EDIT mode, hold down the [SHIFT] button and press [ON] in the Arpeggiator section of the top panel. The screens on the right display the first eight parameters of the Arp Edit mode. To display the parameters of the second page, press the "Down" key [▼] in the PAGE block on the right side of the screens. There is a word in amber letters under the [ON] and [LATCH] buttons: "EDIT" and "SUSTAIN". To access these functions, hold down the [SHIFT] button and press either one. The functions of the arpeggiator are numerous (see page 71 and following pages of manual 1.5).

To be able to use the MACRO commands, you must be on the Hydrasynth home page by pressing the big [ HOME ] button. Macro patches are designed to allow the user to have in-depth control of the synth in real time without plunging into menus and submenus. Located above and below the 4 screens, the 8 assignable encoders and buttons can each be routed to 8 destinations. Complete sound transformations can be made at the touch of a button or by turning an encoder. Each Patch has its own set of 8 macros. The macros are powerful and expressive tools for influencing the program being played through the 8 encoders and knobs in the Master Control section. Each macro encoder allows positive or negative variations of the destination, much like a private modulation matrix. Macros are control assignments to the 8 encoders and their associated knobs that allow you to change certain parameters of a Patch. This feature allows you to have appropriate controls "dedicated" to the Patch. There is a list of 125 different command macros, 8 of which are customizable. In "Home" mode, that of Patch selection and not editing, each "Control knob" paired with its "Control button" around the 4 screens controls up to 8 parameters at the same time: the encoders scan the values of the parameters and the buttons activate/deactivate, trigger or reset them. Modulation/modification levels can be positive or negative, so a macro can reduce the values, increase them or do both at the same time on different parameters. It's easy to see which macros are active on the home page: if a Macro field displays a zero or another number, it has at least one parameter assigned to it. If the Macro field shows a dash, not a number, then it is empty, unused. This feature reminds me of the 4 Control Knob de l'Audity 2000 and those of the FS1R or the Macro Control Box (MCB) of the K5000R. The macros created in the factory have been thought out a lot. These macros are ready to be used very easily and quickly in a Patch and allow sound exploration. The [SAVE] button saves the Patch with the Macro controls. When saving the Patch, the fourth encoder (Control Knob 4) allows you to specify whether the current positions of the Macro encoders will be reset to zero (Return), stored in their current positions (Save) or converted to new values for the parameters they control (Convert). Afterwards, if you find that there are not enough buttons to control Hydrasynth, you can use a control surface, such as BCR2000, and use the MIDI CC and NRPN that are widely implemented in Hydrasynth.

The factory programs are very varied and show the full range of Hydrasynth's sound palette. And in the first ones there are Vangelis-Blade Runner style. The factory patch  A004 BladeTitles PS  makes no mistake. Hydrasynth also makes very well String or Brass Oberheim style. There is even a factory patch, the  A033 St.Genviv FP , which has almost the same name as one of the patches on my Oberheim Matrix-6 :  40 GENVIV    . It sounds the same, with its characteristic timbre. The Hydrasynth knows how to make bass, E. Pianos, Organs, Leads, Brass, Strings, Pad, and strange FX sounds. It excels in evolving, aerial and ethereal pads/layers. I can do Ambient Music same as Brian Eno, Steve Roach or Cliff Martinez atmospheres. The "twisted" arpeggios are not to be outdone thanks to the SWING, RATCHET and CHANCE pots that give them life. Hydrasynth makes very beautiful "analog" sounds and also beautiful "metallic" and/or evolutionary layers which sound "digital". This synth comes out of the beaten integers with its wave tables and its Mutants. The expressivity of the polyphonic aftertouch is a delight, not to mention the "slips" caused on the ribbon. It is an expressive synth. I repeat myself, the sound palette is wide, very wide. So much so that I wonder if having the Ensoniq VFX, E-Mu Audity 2000, Kawai K5000R, Korg Wavestation SR, Oberheim Matrix-6 and Yamaha FS1R don't make a duplicate of Hydrasynth, so much so that Hydrasynth seems to have been inspired by their identity. Hydrasynth is able to compete in the diversity of timbres offered with these synthesizers: various oscillators, wavetables, sharp filters, wave sequences, FM, formants, and arpeggiator. Hum…, and no, they don't quite duplicate. I keep them. They are multitimbral, whereas Hydrasynth is not. And they have some very personal specificities… It will take me a while to explore everything about Hydrasynth. And that's a good thing.

The ASM Hydrasynth is or has been used by Sam Aaron, Roger Austli, Co5ma, Glen Darcey, Jexus, Nick Klimenko, Push-Pull, Aquila Rift, Matia Simovich

Constituant la majeur partie des instruments électroniques actuels, la lecture d'échantillons est un moyen facile de fabriquer des synthétiseurs à synthèse soustractive. En effet, plutôt que de fabriquer des formes d'ondes originales et évolutives, on s'est dit qu'il était intéressant de stocker une multitude d'échantillons sonores et de s'en servir de base pour créer des timbres complexes. Cette technique a rendu très réalistes les instruments basés sur ce principe. A cause du caractère reconnaissable d'un certain nombre d'échantillons, il est parfois difficile de créer des sons radicalement nouveaux. Elle n'est pas a proprement parler une véritable synthèse.

Le principe de la synthèse soustractive consiste à filtrer des signaux riches en harmoniques. Simple à mettre en oeuvre et économique, la synthèse soustractive s'est naturellement imposée sur les premiers synthétiseurs, dès les années soixantes. La synthèse soustractive peut prendre une autre source que le classique oscillateur délivrant des formes d'ondes périodiques simples, que celui-ci soit analogique ou numérique. A partir de la fin des années quatre-vingts, nombre de synthétiseurs soustractifs ont utilisé des échantillons numériques comme source de synthèse. Il peut s'agir d'échantillons d'instruments acoustiques ou électriques, pris séparément (piano, basse, orgue...) ou enregistrés ensembles (section de cuivres, de cordes...), mais également de voix ou de bruits divers. L'efficacité d'un filtre est fonction de sa pente, encore appelée "rolloff" ou "slope", exprimée en décibels par octave (dB/octave) ou en pôle. Le terme "pôle" fait référence au schéma typique d'un filtre ayant une pente de 6 dB/octave. Ainsi, on trouve des filtres 1 pôle, 2 pôles (12 dB/octave), 3 pôles (18 dB/octave) et 4 pôles (24 dB/octave). Additionner les pôles revient à placer des filtres identiques en série. On attribut à Robert Moog l'idée de mettre en série quatre filtres passe-bas, schéma désigné sous le terme de cascade de Moog. Sur un synthétiseur soustractif, deux paramètres principaux permettent d'ajuster l'effet de filtrage : la fréquence de coupure qui est la fréquence à partir de laquelle le filtre va entrer en action, et la résonance (disponible sur certains instruments), qui permet de faire entrer le filtre en auto-oscillation. Celui-ci se comporte alors comme un oscillateur. Il est également possible de modifier l'évolution temporelle de l'effet en adjoignant au filtre une enveloppe d'amplitude.

On attribue à Wolfgang Palm, créateur de la firme allemande PPG, l'idée du principe de lecture par table d'ondes : utilisant le schéma standard du synthétiseur, le système de table d'ondes vient remplacer le classique oscillateur, délivrant des formes d'ondes simples, par une mémoire contenant des échantillons numériques de formes d'ondes, chaque échantillon étant plus ou moins différent de l'autre. Il s'agit donc d'enchaîner en lecture plusieurs formes d'ondes différentes, avec des degrés de fondu variables entre chacune, afin de créer un effet de modification du timbre de la sonorité finale, ou au contraire des changements brutaux de tonalité. Les premiers synthétiseurs ayant utilisé cette technologie furent les PPG Wave. Korg avec le Wavestation, ou Waldorf avec le MicroWave et le Wave, ou Ensoniq avec les SQ et VFX, ont adpoté ce système, couplé généralement à d'autres procédés de synthèse.

La synthèse vectorielle est apparue en 1986 d'abord sur le Prophet VS chez Sequential Circuits grâce à une idée de Chris Meyer avec la complicité de Dave Smith. Utilisant aussi une manette (ou joystick) pour le contrôle de l'effet, la synthèse vectorielle n'est pourtant pas à confondre avec les systèmes de modulation matricielle utilisant le même type de contrôleur. La synthèse vectorielle est en fait, à l'instar de la modulation matricielle, plus un système de contrôle du son qu'un système de modification ou de création du timbre final par des processus électroniques. Contrôlant deux ou quatre sources sonores (oscillateurs, échantillons, opérateurs FM), la manette permet simplement de mixer le volume de chacune d'entre elles. Comme il s'agit d'un joystick, le fait de déplacer le curseur vers un point augmentera le volume du générateur associé à ce point, tandis que celui associé à son opposé se verra diminué dans des proportions inversement identiques. A noter qu'il est également possible d'intervenir sur l'accordage des éléments. Intégrant un système d'enregistrement de la position du joystick, permettant de stocker plusieurs secondes de manipulation et de boucler tout ou partie des événements stockés, associée à un système de déclenchement au clavier, la synthèse vectorielle permet quelques effets sonores intéressants. La vitesse de lecture du déplacement enregistré est par ailleurs modifiable.

La synthèse par modulation de fréquence a été mise au point au début des années soixante-dix par l'américain John Chowning à l'université de Stanford aux Etats-Unis. Naturellement liée aux technologies numériques, seules capables de fournir la précision nécessaire, la synthèse FM utilise un principe de modulation analogue à celui que l'on utilise en radiotransmission : on fait varier la fréquence d'une onde périodique, la porteuse, en fonction de l'amplitude d'une autre onde, la moduleuse. Malgré la simplicité théorique du système et le peu de calculs nécessaires à l'obtention d'un signal, programmer un son par synthèse FM demeure toutefois une tâche délicate car l'intuition n'est pas de mise : une légère modification d'un seul paramètre peut modifier radicalement la sonorité finale, ce qui n'est pas le cas pour d'autres procédés de synthèse.

L'expression en temps réel ! Moduler signifie intervenir sur certains paramètres du son, soit de manière interactive, de la même manière qu'un instrumentiste avec la vélocité, la pression, le Pitch bend, le Breath Controller ou n'importe quel contrôle MIDI, soit au moyen d'un effet prédéfini : enveloppe, LFO… La modulation matricielle est en fait, comme avec la synthèse vectorielle, plus un système de contrôle du son et permet de modifier ou de créer l'allure du timbre final par des processus électroniques. A l'instar des synthétiseurs modulaires, composés de divers modules connectables entre eux, la modulation matricielle permet de créer des connexions variées entre les modules du synthé (LFO, enveloppes, etc.). Il s'agit en fait d'une méthode extrèmement flexible de contrôle du son, permettant d'assigner la plupart des contrôleurs de l'instrument (clavier, molettes, enveloppes...) à des paramètres sensibles (filtre, LFO, amplificateur...). Sur les anciens modulaires, tel le Moog 55, il fallait brancher ("patcher") physiquement avec des câbles entre les modules ou insérer des fiches sur une matrice : jonction en X et Y (souces en lignes, destinations en colonnes) comme sur le EMS VCS3; d'où le nom de "matricielle". Sur les machines modernes sont déjà prépatchés la molette au LFO et le Bender au Pitch (hauteur de la note). Aujourd'hui, l'affectation des modules entre eux s'effectue par logiciel. Les synthétiseurs intégrant la modulation matricielle offrent généralement une souplesse d'utilisation et une palette de possibilités créatives très étendues.

Technical characteristics

Issue dateSeptember 2019
Synthesis typeSamples, Subtractive,
Wave table,
FM (2 operator),
Mutators (4)
Memory219 waveforms in ROM
KeyboardNumber of keys49
Full-Size Keys
Adjusts amplitude velocity response +/- 64.0
AftertouchMonophonic YES
Polyphonic YES
(Pitch and Vibrato)
Ribbon controllerYES
4 octaves (67 cm)
with Theremin mode
Touch PadØ
Potentiometers, encoders and commutators22
Display5 screens OLED
Programs, Singles, Voices (presets/progr.)640 programs
5 banks of 128 patches
Combis, Patches, Performances, Multi (presets/progr.)NON
Polyphony8 voice
Number of oscillators/generators24 oscillators
(3 per voice)
Drum soundsimitation
mono intrument
Effects Spacialisation :
Delay, Reverb

Modulation et Dynamique :
Chorus, Flanger, Rotary, Phaser, Lo-Fi, Tremolo, EQ, Compressor, Distortion
Phrases integrated
External storageASM Patch Manager,
MIDI (DIN)OUT (1) / IN (1)
USBConnectorYES (type B)
Version mini2
Interface MIDI YES
Audio NO
Compatibility OSWindows - MacOS
Driver NO
Class Compliant
FIREWIRE (IEEE-1394) ConnectorNO
Version mini
Interface MIDI
Compatibility OS
Audio outputAnalog Stereo JACK 1/4" TRS
Front Headphones output
Digital NO
OptionsSustain pedal,
Expression pedal
Compatibility programsASM Hydrasynth Desktop

Show some tricks and tips from ASM Hydrasynth…

SOLO function on OSC

When creating a patch you may want to hear one of the sources on its own while making adjustments to that source. Rather than setting the other levels to zero temporarily and restoring them later, Hydrasynth includes a Solo function. It’s easy to use:
Press Control button 8 to toggle Solo from O to On. The Control buttons for all 5 sources will light, which means they are still active.
Press the Control button of the source you want to hear. Its Control button will become brighter than the others.
Press another Control button to solo that source. The rst Control button will dim and the selected one will brighten.
Press Control button 8 again to defeat the Solo function.

Create a CHORD

To create a chord, hold [CHORD] and it will blink. Then play the notes you want the chord to contain. You can press them all at once or one at a time, allowing you to create chords that are outside your normal range. The lowest note you enter will become the root note. When you are finished, release the [CHORD] button.
A chord can contain between 2 and 8 notes.
The chord is not saved with a patch and will be deleted when Hysrasynth is restarted.
Chord mode puts the keyboard in mono mode (priority to the last note).
All notes of the chord will be quantized into notes of the selected scale.
The chord is not transmitted via USB or MIDI. A slave device will only receive the played note.

The ribbon in THEREMIN mode

When the ribbon controller is in Theremin mode, it reserves one voice for itself. This reduces the number of voices available on the Hydrasynth keyboard from 8 to 7.

The [RANDOM] button

Version 1.5 adds a second patch randomization option that generates a new patch by drawing a random selection of values from other patches, themselves randomly selected from other banks. This results in many more usable patches, as it combines various aspects of patches already known to be usable.

The [BROWSE] button]

By pressing the [BROWSE] button, different display settings appear on the 4 OLED screens. This display allows you to change the way the patches are presented in each bank. There are three kinds/sort criteria: by patch number, by alphabetical order or by category (Arp, Bass, FX, Lead, Pad, String, etc.).
The  Browse  page also contains a comparison function, as well as a sub-menu in which you can designate a patch as a favorite. You can store up to 32 patches in your favorites bank for quick access (see page 85 and following of manual 1.5).

The OCTAVE [DOWN] and [UP] buttons

If you wish to hear a Patch in octaves lower or higher than the physical range of the Hydrasynth keyboard allows, you can shift the range by one or more octaves. The Hydrasynth keyboard has dedicated OCTAVE [DOWN] and OCTAVE [UP] pushbuttons above the scroll wheels. Press the [DOWN] button once to decrease the pitch by one octave. The [DOWN] button will blink slowly. If you press it again, the pitch will decrease by another octave. The [DOWN] button will blink faster. The same goes for the [UP] button to increase the pitch by one octave. At the maximum offset, the [DOWN] or [UP] button is lit continuously. To reset the staff, press both buttons simultaneously. The variation range is from -4 to +4 octaves.

EXIT] button

The [EXIT] button lights up when you enter a setting page. Pressing it will take you back to the previous page. It can cancel a process if you decide not to do something (Initialize, Randomize, Save, etc.). The Home Page is the only page where [EXIT] is not turned on, because it is the top level of the Patch.

[HOME] Button

The [HOME] button is located in the center of the panel, under the large knob and the large display. It provides a quick way to exit from Hydrasynth setup/programming mode, and get to where the Macro controls are located. This is called the "Home Page".

crayon The polyphonic aftertouch of Hydrasynth is simply very expressive. The sensitivity to pressure is regular, as much on the white keys as on the black ones. Different parameters of the aftertouch are adjustable in "System Setup" (MonoAftT, PolyAftT, Curve, Delay, Fade, Offset, Release).

crayon The spacialization effects of Hydrasynth are very good bills. The reverb does not sound metallic and the delay is not chemical.

crayon In the VOICE module, the  Warm Mode  simulates the  warm  frequency curve of an analog synthesizer. You can see the effect in the Oscilloscope view, it reduces the top of the spectrum a bit and amplifies the bottom. Hydrasynth takes about 10 seconds to start (in version 1.5.2)… Some patches are a bit long to load. The sound is not immediate.

/!\ Hydrasynth boot in 10 seconds (in version 1.5.2)… Some patches are a bit long to load. The sound is not immediate.

Le Light Show

After unpacking, plugging in and turning on the Hydrasynth, I found its illuminations sober, the large Browse encoder has a white illuminated ring, and the pitch-bend and modulation wheels also have a white ring illuminated from the inside. I change the Patch, and there, the color of the Browse encoder and the pitch-bend and modulation wheels change to blue. Another Patch: pink, another: green, then orange!… Well, I thought  That's okay, it's soft . And then, consulting the manual, I don't touch the Hydrasynth anymore for a few minutes. And then it starts doing the  Christmas Tree . The knurls shine in all the colors of the rainbow, the OLED screens pulsate, the LED rings of the 8 encoders chase. It's party time!!! Well, you can configure the play of light in the system settings (Master, page 1, Control Knob 8: 10, 30 seconds, 1, 5, 15, 30 minutes. Phew, there's OFF!


See ASM Hydrasynth Owner's Manual pdf (3,1 Mb) FR

What is MPE ?

MPE stands for  MIDI Polyphonic Expression . It is a newer MIDI protocol used mainly by other controllers such as Roli, Haken Continuum and LinnStrument. When it is active, the voices in Hydrasynth are divided into individual channels so that each note can have its own pitch bend, timbre and pressure control.
Hydrasynth already supports polyphonic aftertouch, so the MPE pressure is automatically mapped to the poly aftertouch. Any patch that uses PolyAftT as a mod source should automatically respond to the pressure sent by an MPE controller.

MacTalk Until 2019, in new hardware, only the CME xKey controller had polyphonic aftertouch. But the low keystroke amplitude of the xKey does not allow for precise playing.

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