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Yamaha AN1X

Analogue Physical Modelling Control Synth By Martin Russ
Published August 1997

At £899, the AN1x is one of the most affordable physical modelling synths on the market — and it's no less than 10‑note polyphonic, with a host of features designed to bring out the control freak in you. Martin Russ follows up our exclusive preview with this in‑depth studio test.

When I did the preview of the AN1x a few months ago (see SOS April '97), the prototype unit was in transit between NAMM and Frankfurt, and so time was short. Even though I'm used to the rigours of limited time being available for a preview, things were complicated because only a Japanese manual was going to be available. I'm still a beginner in Japanese (Nihongo o amari hanashimasen), and, as it happened, the manual arrived after the deadline anyway, so the preview necessarily concentrated on what the AN1x was like from the outside, since trying to figure out how something works beyond the sounds and the front‑panel controls can be quite tricky. However, I've now spent several weeks with my blue wedge‑shaped friend, and it's about time to prise my fingers from it and reveal all.

Writing about the AN1x is not straightforward — if you thought it was just another digital modelling synthesizer capitalising on the current analogue retro revival, you'd miss out on the true appeal of the instrument. Ordinarily, in a review of a synthesizer, I would expect to write mainly about the sounds and the synthesis technique used, and cover the user interface, MIDI and control functions as part of the panel‑control description. The AN1x does not fit into this cosy format. It is quite some time since I last used something where the synthesis method was arguably secondary to user interaction and the control functions — my WX11 wind controller springs to mind.


The AN1x throws away several conventions about how a synthesizer is organised, and does things in a new and very different way. The distinction between a patch and a performance usually found on modern synths is gone: the AN1x's basic unit of sound storage is a complete snapshot of the total sound — or rather, two sounds, plus all arpeggio, sequencer and other associated settings.

At first glance, the AN1x appears to have virtually the standard monosynth architecture. Two oscillators and a noise source are mixed together and pass through a timbre‑shaping filter, emerging from a volume‑controlling amplifier. Now I could be pedantic and take issue with Yamaha for calling the Oscillator, Filter and Amplifier by the 'Voltage Controlled'‑based acronyms VCO, VCF, and VCA, when the whole concept of voltage control inside a digital emulation is ludicrous. But I can't see any reason to complain about the use of the word VCF for something which, although only a mathematical model of an analogue Voltage Controlled Filter, sounds, feels and behaves just like a real VCF.

But unlike a monosynth, there's rather more to the AN1x than this cursory overview suggests. Firstly, for all but the simplest of operating modes, the AN1x produces stereo sounds. Secondly, the richness of the detailed synthesis implementation is rather unexpected. Having learnt my trade on analogue monosynths such as Minimoogs and ARP Odysseys, the first polyphonic synthesizers came as quite a shock to me, because cost‑reduction had forced manufacturers to pare away all but the most essential elements. So single‑VCO or (more often, digital‑DCO, single‑EG‑equipped polysynths appeared, often with a simple chorus effect tacked onto the output to try and restore the gorgeous detuned 'rolling' sound of the monosynth. There were exceptions, of course: the Yamaha CS80 cut no corners, and the AN1x follows in its footsteps.

The AN1x is rather more than a simple monosynth. It's more like ten rather well‑equipped monosynths. There are two VCOs, with detuning and LFO‑driven PWM for smooth, rounded pads and basses, and these can can be sync'ed together, so that the slave is forced to operate at multiples of the master's frequency, even when the slave's frequency is altered with an envelope, the LFO, or a knob controller. You can also use one VCO to frequency‑modulate the other, and, by combining Sync and FM, it's possible to produce some unexpectedly non‑analogue sounds. If you've ever used FM on an analogue synthesizer, you've probably been frustrated by how slight imperfections in the VCOs can restrict the usable range of decent sounds to a span of a few notes, or perhaps even just one — and even then the effects of drift or temperature are heightened alarmingly. Being digital, the AN1x's VCOs suffer none of these problems, so the sync'ing and FM functions make the very first part of the sound‑creation process considerably more productive than you might have imagined.

The main LFO has a remarkable selection of waveforms — not only the usual sine, triangle, sawtooth, square and sample & hold, but additional ones with DC bias, phase inversion, and an extra sample & hold waveform — that's 21 waveforms in total. The second LFO offers a triangle waveform only, and is intended for PWM control and additional vibrato. By using the so‑called 'Free EG' facility (see later for full details), you can record your own synchronous or asynchronous modulation waveforms to control most parameters.

After years of not understanding why some people raved about arpeggiators, I have now undergone a revelation — and it came in a wedge‑shaped blue plastic case.

The VCF acts as the focus for the sonic raw material. As well as the VCO outputs (plus some intriguing 'internal' extra waveforms when you use sync), there's a noise generator and a ring modulator. Ring Modulators got stuck in a rut producing Dalek voices many years ago, but, as the CS80 showed, a bit of ring mod can work wonders. The outputs of the VCOs actually have their own 'low‑pass' filters, which allow you to pre‑set how wide the filter can open, and thus its brightness, and let you balance them against other bits of the mix. The final input to the filter is an unusual one: the output of the VCA. Feedback is normally the province of modular synthesizers, and certainly not polysynths. As a nod to the monosynths of old, the VCF is preceded by a high‑pass filter — which allows you to remove the low frequencies which can so easily muddy the sound when you mix together lots of low‑pass filtered synth sounds.

Filters are personal things. Ladders, state‑variable loops, 2‑pole, 4‑pole and 6‑pole variants all go together to produce the characteristic thin and buzzy or dark and moody feels of the analogue filters of old. Yamaha have provided 2‑, 3‑ and 4‑pole low‑pass filters, plus band‑pass, high‑pass and band‑reject ones. The VCF sounds that most people remember are the strident and synthetic 2‑pole 12dB/octave type, and the 4‑pole, resonant 24dB/octave type. The AN1x sounds very similar to the real thing in both cases — by which I mean that if I do an A/B comparison with my analogue 24dB ladder filter, I can detect some differences but I'm not sure exactly what they are. Without the benefits of that comparison, the AN1x's filters sound like analogue filters. In fact, as I said in my preview, you very quickly forget that this is a digital instrument. I treated the AN1x as if it were the impossibly perfect analogue synth that I dreamed of all those years ago — and it did almost nothing to shatter that illusion.

These days, no synthesizer would be complete without the obligatory effects section on the output, and the AN1x is no exception. There are three separate sections: Variation, which offers 14 types of Chorus, Flange and other specialised effects; Delay, which gives five Echo and Delay effects, including a delay which is synchronised to the arpeggio or sequencer tempo setting; and Reverb, which provides eight different types of reverb. There is an extra section, which provides 3‑band EQ control of the tone of the instrument, but this is not affected by the effects bypass, which might be a trap for the unwary!

Front Panel

I won't bore you with a detailed description of the AN1x's front panel, but its organisation is interesting. The pitch‑bend and modulation wheels are in the traditional 'left‑hand side of the keyboard' position; above them is the ribbon controller; above that are the scene switches, and then the volume control. The ribbon controller is a revelation, with a crisp feel that puts it into a different league to the old ribbons found on Multimoogs (it also offers both sideways and pressure sensitivity). The positioning encourages you to use the ribbon with your left hand when you're not bending or modulating.

The eight assignable knobs can be used to control seven pages of synthesizer parameters, plus an eighth page which is preset to provide some very useful quick edits by Yamaha, but which you can edit to suit your own preferences. The seven pages of programming parameters are much easier to use than you might think, and I soon found myself hopping from page to page without getting lost. But you do need to refer to the front‑panel graphics to keep your bearings. The knobs have a built‑in switch that you press to confirm where the AN1x thinks the knob is, and you then turn the knob to position the shaded segment to the flashing segment on the display.

The custom LCD is small, but backlit, with a pale green light, and gives plenty of feedback about what's happening inside. Different modes tend to re‑use the same bits of the LCD, which isn't as awkward as it sounds — just a bit stingy in these days of huge LCDs. Then again, for the price...

The Program Change keypad needs little explanation, so I'll move swiftly on to the 'matrix' to the right of the keypad: a rotary switch is used to select the row, and ten up‑down rocking switches select (and control) the columns. Each cell in the matrix contains a parameter, whose value you can change with the rocking switch. This simple arrangement controls parameters pertaining only to 'overall' functions — arpeggiator and sequencer settings (see later), effects, and so on. The actual sound‑tweaking is accomplished via those eight knobs on the far left, which encourage you to make edits. I didn't find the matrix quite so welcoming, and it took me some time to get used to the allocation of the parameters to the rows, which isn't completely logical in some places. However, in its defence, the matrix does actually provide you with a map of each parameter, so there's no need to go searching through lots of scrolling menus to find something. You may not even need to do much with the matrix, since the AN1x's comprehensive patch storage means that lots of extra information is stored away with the sound. This minimises the need to change things when swapping from one patch to another.


The AN1x's 61‑note keyboard, with velocity and pressure (aftertouch) sensitivity is part of a whole array of real‑time performance controllers. Its arpeggiator boasts 30 different patterns, including some which play chords, and others which randomly select notes from those you are holding down. The 16‑step sequencer uses the same eight knobs that are used to program the sounds, and allows real‑time changes to be made to the sequence that is playing.

Having a short repetitive sequence playing cries out for some sort of slow modulation: filter sweeps, timbre changes, and so on. The AN1x allows you to morph between two sounds as you're playing, and has 'Free EGs' (Envelope Generators), into which you can record your own parameter changes — rather like a dedicated controller recorder. The sequencer provides 128 preset patterns and 128 user memories — and the pattern is stored as part of the patch, so that when you select a patch the sequence is automatically loaded and ready to go. MIDI clock sync, looped patterns and syncopated/swing rhythms all make the sequencer a powerful ideas generator. Best of all, the arpeggiator and patterns can be routed to the MIDI output, on the same channel as the main output from the keyboard, or on separate channels. Yamaha warn that using the same output channel for all of these outputs can cause problems, and I can confirm that it is possible to produce 'stuck' notes on external MIDI equipment (even on Yamaha stuff) — so you've been warned! Just about the only thing you can't do with the arpeggiator and sequencer is run them at the same time.

But there's rather more to the AN1x's control feature set than this. Some aspects of the machine's operation are what you might expect: different modes give you variations on Unison, Dual and Split voices, based on the idea of having two different sounds stored as part of a single patch. These two sounds determine how the morphing works, and are called Scenes, so you can have two variations on the same sound by tweaking those eight parameter knobs, or even editing one of the Scenes, leaving the other unchanged, and then mix them, morph between them by using the modulation wheel, and save the edited sound as one patch.

The arpeggiator begins to stretch things a little. You can have the whole keyboard driving the arpeggiator, and either one or both Scene sounds playing the arpeggio. If the keyboard is split, you can have notes to the left of the split played by one Scene sound, whilst the other side of the split plays normally. There are quite a few combinations of splits, Scene assignments and keyboard modes, but the upshot is that most combinations of sounds, arpeggios and normal playing are available. As with the sequencer, all these settings are stored away as part of the patch.

The step sequencer offers the same sort of flexibility. Although it's only a 16‑note affair, you can use keyboard splits to either shift the selected pattern in pitch, choose another pattern, or do both (the left‑hand side of the keyboard selects the pattern, the right‑hand side shifts the pitch), making it very versatile and powerful. Combined with different loop types (forwards, backwards, alternate, and so on) and Scene sound settings, the sequencer's additional 'feel' controls might be seen as overkill. These control 'swing' by shifting the timing of some beats, or changing the velocity ratio between the highest and lowest velocities (similar to using an audio expander or compressor), or altering the gate time. Wow.

Each sequence step can be entered using the appropriate knob — there are two 'pages' (1‑8 and 9‑16) for the 16 steps. You can set note number (there's a neat 'extra' here: pressing the knob down to get fine control helps set the note quickly); velocity; gate time percentage (1‑200%, so you can force legato playing); and even a MIDI Control Change value to be sent with each step. You can also make the sequencer or the arpeggiator automatically hold given notes, so that you don't have to keep your hands on the keyboard — play along with an arpeggio or sequence with both hands pecking away at the keys.

The Free EG is really an extension of the idea of Control Changes in the step sequencer. Imagine having four separate tracks of control information assigned to specific parameters inside the synthesizer, and which can either be sync'ed to the arpeggio or sequencer clock, or run asynchronously for a given time and then looped, and you have the Free EG controller (see diagram, right). Tracks can be recorded separately or all at once, and it's surprisingly straightforward to use. Free EG settings and information are, again, stored with the patch, and are very useful for providing evolving or constantly changing timbres.


In the sound department, the AN1x's basic architecture produces a series of variations on synth brass sounds, with woody basses and clichéd resonant decaying filter sounds. The sync function facilitates searing lead lines that encourage soloing, and also produces some remarkably bright bass sounds. The FM and ring modulator give you the bell‑like timbres and electric pianos that extend the synth's repertoire slightly beyond the traditional analogue synth range, whilst FM and sync, coupled with feedback around the filter, create sounds which are well beyond what I associate with analogue, and more like S&S or even physical modelling. There's rather more to this instrument than slushy pads and resonant sweeps.

And there's more — more than I can include in this review. Don't forget that having two Scenes means that you can not only layer two different sounds, but also move smoothly from one sound to the other. Yamaha told me that they had fixed some problems I reported with the morphing in the prototype, used for my SOS preview; and virtually all of the zipper noise has gone, so the algorithms used to control the change from one sound to the other are now very effective. Wearing my 'picky' hat, I did find one factory sound which had some vestiges of unwanted noise (BR:004 Major Brass), but this was the exception, not the rule. On the subject of factory sounds, I always advocate listening to them with an analytical ear, and then replacing them with your own sounds. Not bothering to get into programming an instrument like this is almost a crime.

Since those eight little knobs are just waiting to be tweaked, making real‑time changes to sounds as you play them is a doddle. I must confess that I've become rather addicted to raising the level of the echoed signal on sync'ed lead‑line sounds at appropriate moments, and changing the VCF cutoff frequency is such a powerful timbre manipulator that you wonder why it was ever locked away behind displays and parameters. Yamaha have obviously spent some time thinking about how best to maximise the implementation of the eight assignable knobs — so knobs 1 and 2 normally control attack and decay, 5 controls filter cutoff, 6 controls resonance, and 7 and 8 allow control over the effects section. Knobs 3 and 4 are assigned to suit each voice, but they tend to be VCO‑orientated. If you're not sure what a particular knob will control, press it twice (almost like double‑clicking as you would with a mouse) and the assigned parameter then appears on the top line of the display. Simple, neat, and in these computer‑literate times, almost intuitive!

The Manual

Yamaha's manuals have been very similar for many years, so this one came as a complete surprise to me. It looks more like a magazine than a manual, and it has colour adverts for the MU90R, EMX640 and A3000 as part of the cover. Inside, the 122 pages start with an overview, then run through the instrument in more detail, describing how to approach learning how to work with it. Then there's a detailed description of each function, followed by examples of how to program a few sounds. The whole thing is chock‑full of little notes, hints and tips on how to do useful extra things. Overall, it's one of the nicest manuals I've seen in some time, with a clarity that belies the complexity of what is being described.

And So...

The AN1x is the first synthesizer in a long time that grabbed me, shook me, and screamed "Play me!" rather than whispering "Hey, I'm a technically sophisticated synth programmer's dream". It's definitely a player's instrument, and, although there's plenty there for a programmer to work with, I suspect that the distraction of interacting with it is going to make anything other than quick edits rather hard to accomplish for many people. After years of not understanding why some people raved about arpeggiators, I have now undergone a revelation — and it came in a wedge‑shaped blue plastic case.

At the price, the AN1x has to be a dead cert for a runaway success. I only hope Yamaha are ready for hordes of performance‑frustrated keyboard players descending on their dealers and demanding one.

Factory Patches

When you try out the AN1x in your favourite music shop, here are my recommended first stops in your exploration.

  • 001:Co:Relaxx. Try the ribbon controller.
  • 011:Sq:Alan. Try assignable knobs 7 and 8, the ribbon, and the morph wheel.
  • 017:SQ:Doves. Again, try the assignable knobs 7 and 8, the ribbon, and the morph wheel.
  • 021:Co:Vinnie. Pattern pitch shift below the split. Solo above the split.
  • 049:St:Analog. Rich and slushy.
  • 058:Sc:Dust. Press both Scene buttons to enable morphing. Press the Arpeggio/Seq button. Hold down some notes, and tweak assignable knobs 5 to 8.
  • 065:Ld:Hard Sync. Play and use assignable knob 7. Repeat ad infinitum.
  • 085:Pd:Polyswell. Assignable knobs 7 and 8 again.
  • 106:Fx:FreeEGRhthm. Just play.

The Future

It used to be that Yamaha released the pro/flagship version of an instrument first, and then pared away some of the more esoteric features for the mass‑market release. The DX1 followed by the DX7, or the VL1 and the follow‑up VL70m are typical examples. The AN1x is evidence of a new strategy — the price, casing, small LCD and lack of memory card or floppy disk drive suggest that this is not intended as a pro/flagship instrument. When I quizzed them, Yamaha didn't give much away about the future, but from the available evidence of recent releases (VL70m, AN1x, MU90R,) I imagine you can guess what might be likely.

Apparently, the original planned name for AN1x was the CS3x, but the re‑naming makes possible a whole new series of 'AN' analogue modelling synths, whilst the CS series can continue with S&S.

Brief Specification

  • 61‑note keyboard with velocity and aftertouch.
  • 10‑note polyphony (maximum).
  • 2‑part multitimbrality (maximum).
  • 128 Factory and 128 User presets.
  • Arpeggiator with 30 patterns and 10 timing sub‑divisions.
  • 16‑step sequencer with 128 presets and 128 user patterns.
  • Free EG controller recorder.
  • Effects: Variation (Chorus, Flanger, Symphonic, Phaser, Auto Pan, Rotary Speaker, Pitch Change, Aural Exciter, Compressor, Wah, Distortion, Overdrive, Amp Simulator); Reverb (Hall, Room, Stage and Plate settings); Delay (five types); EQ.
  • Scene 1 and Scene 2 knobs.
  • 8 assignable control knobs.
  • Pitch‑bend wheel.
  • Modulation wheel.
  • X‑Z ribbon controller.
  • Backlit LCD display.
  • Stereo audio output; 3 footpedal inputs; MIDI In, Out, Thru; DC In.
  • External PSU.

Hidden Extras

For those brave souls out there who like to know everything there is to know about an instrument, there's a hidden 'test' mode in the AN1x, intended for factory and servicing use only. You enter it by powering up the synth whilst holding down the '0', '‑' and '+' buttons on the keypad. The '+' button then advances through the tests, and the '‑' button goes back. The 'Store' button enters a test routine and acts as the 'Yes' button, whilst the 'Portamento' button exits a test and doubles as the 'No' button. You can do all manner of nasty things with this mode, so don't!


Since this review has constantly referred back to analogue synthesizers, this seems like a good point to refresh some of the terms that were in common usage fifteen years ago.

  • EQ Equalisation.
  • FM Frequency Modulation: a synthesis technique.
  • LFO Low Frequency Oscillator: vibrato, tremolo, and so on.
  • PWM Pulse Width Modulation: waveshape changing.
  • VCA Voltage Controlled Amplifier: volume control.
  • VCF Voltage Controlled Filter: timbre control.
  • VCO Voltage Controlled Oscillator: sound source.

And how about a term that has been in popular usage for only about five years:

  • S&S Sample & Synthesis: sample replay.

Comparison: AN1X & CS1X

Because it looks like a CS1x, there are bound to be people who will think that the AN1x is an expanded or cut‑down CS1x. In fact, the two are very different in many ways. The outer casing is just about the only common bit. Here's a quick guide to the differences:
S&SAnalogue Modelling
Sample‑basedAnalogue emulation
480 patches128 patches
32 note poly 10 note poly
Ribbon controller
Arpeggios & Sequences at MIDI Out
Drum sounds
2 assignable knobs8 assignable knobs


  • 'Analogue' sounds and more — you forget it's digital.
  • 10‑note polyphonic.
  • 61‑note keyboard with aftertouch.
  • Neat arpeggiator and sequencing.
  • MIDI Thru.
  • Editable effects.


  • User interface is not 'one knob/switch per function'.
  • External power supply.
  • No computer MIDI interface.
  • Way too affordable.


Don't hesitate, BUY!