Hypersynth Xenophone analog synthesizer reviewed

July 24, 2015

When a new synthesizer comes out from a country that wasn’t previously known for making electronic instruments, I’m always curious and excited, and the Hypersynth Xenophone is no exception. Persian developer Hypersynth was previously known for their software instruments and editors, and this monophonic analog synth module is their first hardware offering. As we’ll see, it offers a lot of sound-shaping power and a unique sonic character for the price.


Enclosed in a small lightweight box with wooden sides (either flat or for a little more money, angled sides that turn the unit into its own desktop stand), the Xenophone is a ee-oscillator monophonic synth module with analog oscillators and filters, digital envelopes and LFOs (like many modern analog synths), and digital effects to round off the sonic chain. Editing is based on the interaction of its 26 rotary encoders with the info given by its two-line display. With two sub-oscillators, three LFOs, three envelope generators, three ring modulators, a multimode filter with ten modes, and a vast modulation matrix, there’s plenty to keep a dedicated programmer busy. To store your creations, you have 896 memory slots, organized in seven banks of 128 patches each. The manual is well written, and while it assumes a basic knowledge of analog synthesis, it’s quite exhaustive.

On the right side of the Xenophone’s display, you’ll find the only detented encoder (the other 25 are free-running). Its main function is to navigate thru the various pages, wherein you can adust the values of two to four parameters per page via the four “soft” encoders beneath the display. However, the most-used parameters also have dedicated knobs, which you can grab at any time on the various sections of the panel.  This causes the screen jump to the appropriate page, though there’s a setting if you prefer to prevent that. In addition, a button accesses frequently used categories of parameters directly, and also a submenu that scrolls through every category.

Something that left me perplexed is that on several pages, the “soft” knobs have no effect on the parameters which also have dedicated knobs on the panel; you have to use their dedicated knobs instead. I’d prefer both options: Soft for when I’m focused on the display, dedicated for live performance. Hypersynth is considering addressing this in a future update. 


The Xenophone offers an exceptional choice of possibilities for the oscillator section. Let’s start with oscillators 1 and 2, which are nearly identical: In addition to the usual sawtooth, square and triangle waves, you have combinations of square with sawtooth and with triangle, and also a “stepped” square, which is the combination of two square waves. For each of these waveforms you can set and modulate both the shape (morphing from square to sawtooth or vice-versa, for example) and pulse width. With a midway-morphed waveform, the PWM parameter only affects the square component of the wave, leaving the other intact. You can also set the phase of each oscillator, either forcing them to start at a specific point or letting their phase free-run. This can make a huge difference in the tone when combining two or more oscillators.

Oscillator 2 can be hard-synced to oscsillator 1. Furthermore, you can replace the oscillators with the result of ring-modulating square waves between oscillators 1 and 2. Impressed yet? Want more? Both oscillators 1 and 2 have dedicated sub-oscillators (again, producing square waves), which can be tuned either one or two octaves below, and also can be put into ring modulation with their parent oscillators. Another important parameter is Drift, which gives varies the oscillators’ random detuning and ranges from imperceptible to pretty wild.

There’s also FM: The triangle wave of oscillator 2 can modulate oscillator 1 in the audio range. Here, the possibility to disable keyboard tracking for either oscillator comes really handy for certain types of sounds.

Is a third oscillator necessary when you have all these goodies? Hypersynth seems to think “well, mayb,” as they treat it as a afterthought. First, it can only produce a square wave. Second, it shares a VCA with the noise generator, so you can’t use both it and noise at the same time This is one of the few shortcomings of this instrument. On the positive side, the noise source provides white, pink or red noise, plus something called C64 (an apparent homage to the Commodore 64 computer’s SID audio chip), which sounds like a kind of tuned noise. 

Mixer and Filter Section

There Xenophone’s panel lacks a dedicated mixer section, but couple of pages in the display let you adjust the levels of the main and sub-oscillators. The mixer can be slightly saturated by raising the levels, but be careful not to push to the point of unwanted distortion, as we’ll see later. There’s also a level control for the ring modulation between oscillators 1 and 2.

Next to this you’ll find portamento/glide. It has four modes: Fingered or permanent, constant rate or constant time. I would have liked a bit more resolution for the fastest settings.

Then, feedback does a lot to make the sound bigger and tighter, although it reduces the effect of filter resonance. Even more than for the other levels, you have to be careful with feedback level, as it could induce some clipping.

The Xenophone has a single filter offering a choice of ten different types. Both lowpass and highpass modes have a choice of 12-, 18-, or 24dB-per-octave slopes; plus, you get 12dB or notch and two different combinations of lowopass and highpass in series. Very good.

The Filter FM parameter routes oscillator 1 to audio-rate modulation of the filter, disengaging it from the audio mixer at the same time.

So how do these filters sound? I’d say that they tend to sound a bit “pushed,” giving an impression of slight saturation. The difference between the different slopes is very evident to the ear, but the overall personality tends to stay constant. As to the resonance, it’s not the kind that thins down the overall timbre as you raise it; on the contrary, it seems to add to the basic filter body, contributing to a generally robust, thick sound. 

Envelopes and LFOs

Each of the three envelopes starts with the classic ADSR configuration, with the addition of delay and hold stages. Then you can set response type for the envelope: linear, or three different types of exponential or logarithmic. Next is the Trigger Mode, which is where you decide how your envelope will restart at each key press: from zero, from the current level, or it can simply run until the end of its cycle. The envelopes can loop, too; a very desirable feature. As is often the design choice, envelope 1 is hardwired to amplitude and envelope 2 to filter cutoff, but you can set any other routing you like from the modulation matrix, and envelope 3 can be assigned freely.

Each of the three LFOs has six waveforms: sine, triangle, sawtooth, square, sample-and-hold, and finally sample-and-glide, a very useful function which smooths the transition between consecutive values of sample-and-hold. LFOs 1 and 3 have a separate “Target” section, with a limited number of often-used parameters (different for each LFO) to be used as destinations, without taking up one of the slots in the Mod Matrix. You can set each LFO to restart its waveform with every key press, only when you play staccato, or to run freely. The LFOs can be synchronized to clock (MIDI or internal), with note values between half- and 32nd-notes.

Modulation Matrix

When I first read that the Xenophone had eight “free” modulation slots with a huge list of sources and destinations, I thought of my Dave Smith Mono Evolver Keyboard, which only has four. So I anticipated going wild with multiple modulations—but then I noticed the Xenophone lacks most of the hard-wired modulations the MEK has. So, even with eight modulation routings, I found myself hitting that ceiling several times. On the other hand, Hypersynth really did their homework with the list of destinations. For example, you can modulate individual envelope segments, which I find extremely useful. You can even modulate the depth of another modulation routing. Yes, the programmer in me cries for more, but realizing that many analog synths—especially at this price—have only a few hardwired modulation routings, I shouldn’t be complaining too loudly.

Arpeggiator and Sequencer

The sequencer and arpeggiator are of course close relatives, although only one or the other can be used at any given time. Sequences are saved with patches.

Arpeggios can go up, down, or up/down. Adjustments can be made to tempo, division (from half- to 32nd-notes including triplets and dotted notes), duration, and range (one to three octaves). Latch lets the arpeggio or sequence run even after the keys have been released.

In the sequencer, notes can be input from either the screen or incoming MIDI data, and pauses can be inserted. Each of the four tracks has 16 steps maximum; track 1 is dedicated to notes, track 2 to velocity values, and tracks 3 and 4 can be assigned to any parameter. Sequences can be gated by MIDI notes or set to run freely. They can be transposed by incoming note numbers, and incoming MIDI velocity values can override the velocity track if desired. There’s also a parameter called Hold Step, which disables the gate-off signal for any given note. That’s used to make the pitch of one step in the sequence glide to the next, vintage Roland-style; the Portamento knob sets the speed of the glide.

Next up are the Slew Rate parameters on the Velocity and Assignable tracks. The slew rate here works like a lag processor, which according to the manual “limits the rate at which a signal can increase or decrease in value.” In other words, it acts as a smoother/compressor of the values stored in a track. Sequencer tracks also appear as sources in the modulation matrix, so one application for smoothing between consecutive steps would be to use the tracks as extra LFOs, driving any parameter you like.

Output and Effects

At the output stage, in addition to Main Volume and Balance there are two different effect sections: Distortion and Digital Effects (DFX).  The (analog) Distortion has five possible settings: Off, Light, Dirty, Harsh and Massive. They’re perfect for many styles of electronica, but for sounds that require just a slight amount of saturation, overall the Hypersynth’s distortion tends to change the timbral character of a sound a bit too much, even at its mildest setting. Lowering the output level of the oscillators didn’t really help, so I just had to give up using Distortion in some cases.

The Digital Effects are essentially reverb and delay, with different algorithms. They generally sound good and are a nice addition, especially for live playing. They’re not very editable, though—for each of the eight algorithms (which include various rooms and halls as well as a Ping-Pong delay) you can only adjust three parameters. These are generally well chosen, though, and it’s nice to be able to bring a true analog synth to a gig knowing that you won’t need extra effect pedals for a little sweetening.

A word of warning: with such a complex signal path, there are several places where poor gain-staging decisions on the user’s part can cause unpleasant clipping artifacts, especially if you apply ample doses of feedback, resonance, FM, and/or distortion. The solution is usually to lower the levels in the mixer section. 

Software Editor

The Xenophone comes with its dedicated software, which you can download from the company’s website. With an instrument that’s so totally editable from the front panel and 896 memory slots for patches, I don’t use it much. If you’re concerned with DAW integration, however, it lets you automate every parameter in the Xenophone engine (both MIDI CCs and NRPNs) from your host software. 

When a new synthesizer comes out from a country that wasn’t previously known for making electronic instruments, I’m always curious and excited, and the Hypersynth Xenophone is no exception. Persian developer Hypersynth was previously known for their software instruments and editors, and this monophonic analog synth module is their first hardware offering. As we’ll see, it offers a lot of sound-shaping power and a unique sonic character for the price.


Some on the Internet have cleverly observed that the Xenophone has a sound reminiscent of vintage Italian synths such as the Elka Synthex or Crumar Spirit. I find this to be true enough, but the Xenophone can also show a darker side of its soul. With its wide choice of waveforms, the robust and beefy filter resonance, and a vast array of modulation routings, it seems well suited to large, generous timbres. Brassy CS-80-like sounds are easy to achieve. In addition, the distortion section, the more complex filter combinations, the ring modulators, and so on seem perfect for programming more “acidic” sounds. Several of the preset patches seem to lean in that very direction, especially when the arpeggiator/sequencer kicks in.

The Xenophone has lots to offer to the synth-obsessed electronic musician. It can sound both vintage and modern, and its architecture allows a great deal of flexibility at a very interesting price. Of course, you have to like its basic sound quality; which, if forced to try and give a short definition, I would call “clear and tight.” Then there’s the price: It’s not be the cheapest monophonic analog synth out there, but it’s far closer to that end of the price spectrum than to the expensive end.


Rich, clear analog sound with a serious personality. Huge set of features with lots of modulation options. Good price/performance ratio.


Third oscillator can’t be used at the same time as noise generator. Some aspects of the OS can be confusing. When used, distortion tends to alter overall sound too much, even at low settings.


A very strong contender in the crowded “modern mono” market, with a powerful sound and great features at a very attractive price.

flat sides: $899 direct | angled sides: $922 direct | shipping to USA: $85


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