Yamaha VL70m

At under £500 — less than an eighth of the original price of its VL1 predecessor — Yamaha's VL70m constitutes a brave attempt to bring physical modelling synthesis within the reach of all musicians. Martin Russ joyfully welcomes this monophonic modelling module...

I can live without a VL70m. I can, definitely. No problem. I've managed for a couple of years with only minor withdrawal symptoms from the VL1. Spending a few weeks learning about the VL70m won't affect me at all. No sweat. And then I just send it back to Yamaha... NYAAAARGH!

Technology has a nasty habit of becoming affordable. If you bought one of the first CD players, you would have had very little change from a grand, and CD‑ROMs also used to cost thousands of pounds. In these technologically‑aware days, it's hard to imagine (or remember) what it was like when all TVs were black and white, and when a scratch could ruin a treasured LP. The pace of progress continues to increase — in five years, CD‑ROM prices have changed so dramatically that the disks have gone from being major purchases made only by multi‑national corporations to being virtually given away on the front cover of magazines.

The plummeting cost of physical modelling synths provides another fine example of the benefit of developing technology to the end‑user. The Yamaha VL1 (which I reviewed in SOS July '94) was the first synthesizer to bring the computationally‑intensive technology of physical modelling out of the world of academics and researchers, and into the hands of musicians. It was crammed full of DSPs, and cost £4000. Two years later, the first of the second generation of Yamaha physical modelling synths costs less than £500, and there's a deceptively simple circuit board inside, with only a few chips on it. It is much harder to try and say that you can't afford a VL70m.

Appearance & User Interface

The VL70m is a synthesizer expander module. 1U half‑rack cases all look much the same unless you really work hard, and Yamaha have striven to echo the gold, cream and dark brown colouring of the original VL1 by reworking an MU80 case. The result is that the large, backlit green custom LCD display dominates a front panel which looks rather like a top‑end hi‑fi separate. It's by far the classiest‑looking module I've ever seen. OK, so it isn't quite up to the real wood veneer of the VL1 — but then there's not much room for any wood!

There is no skimping on buttons: there are six for the different modes, and nine control/editing buttons. As with many modules, the 4x17‑character display tries to squeeze in as much information about the basic configuration as possible. The VL70m's display uses some custom icons and a bit‑mapped graphics block to make this possible. The latter is put to good use when you first press the combined power switch and rotary volume control to switch it on — the 16x16‑pixel graphics block shows a lighthouse with its searchlight beam sweeping across towards you. Other icons include a finger, someone blowing, a speaker, a suitcase, and an accordion. I couldn't figure out what the icon on the main page was, and had to resort to asking Yamaha — not quite the deep, probing type of question they normally expect from me! I'll save you from the embarrassment by revealing that it is someone playing a keyboard.

Despite all those buttons, and the large display, changing the parameters displayed on the main screen involves moving around with just a couple of cursor buttons, and changing the values with another pair. Beyond that, there's a similar 'scrolling and changing' user interface for all the other settings — and there are plenty of things to alter, even though there are no built‑in editing facilities for the physical modelling synthesis engine itself. Incidentally, although all the main screen parameters can be edited at all times, some of the deeper edits can't be made whilst the VL70m is playing notes.

I'm pleased to report that Yamaha have included their 'double‑click' shortcut for showing MIDI messages: press the 'Enter' button twice quickly and you see either the controller message or the SysEx message for the currently‑selected parameter. This isn't just for people who like to write their own editors or mixer maps — it's actually very useful for typing those messages directly into sequencers, and saves all that messing about trying to record MIDI messages.

Yamaha include a 3.5mm stereo headphone socket jack on the front panel, as well as inputs for a breath controller and a WX wind controller. Putting these inputs on the front panel brings these often‑overlooked MIDI controllers into sharp focus — remember that a keyboard is not the only way to play a module. Yamaha's breath controllers have improved incrementally with each generation, and the third‑generation BC3 (which Yamaha sent along with the VL70m to help with the review) is the best yet, but still not quite perfect — see the 'Breath Control' box elsewhere in this review. WX‑series wind controllers are something else entirely: the WX7 (reviewed way back in SOS December '87) and WX11 look like alien clarinets or oboes, and when they were used to control TX81Z‑type FM sounds, they sounded just a little too synthetic. But when you combine the formidable range of control they provide with a physical modelling synthesizer like the VL70m, then you are talking expression in its most interactive sense. My second‑greatest regret is that I was never taught to play the piano as a child — but my greatest regret is that I can't play a wind controller properly.

The rear panel has MIDI In, Out and Thru sockets, stereo audio quarter‑inch jacks and a DC In socket for the external power supply. There is also a mini‑DIN 8 socket for connecting the module to a computer serial port, and a 4‑position switch for choosing MIDI, Macintosh, or two varieties of PC (IBM‑compatible and NEC PC). Having a combined MIDI interface and monophonic synthesizer is an intriguing concept; you normally need a little more polyphony than one note to make best use of a computer‑based MIDI sequencer, and so it is reasonable to assume that you would need a polyphonic expander module in addition to the VL70m. I suspect that adapting the MU80 case meant that it was easier to include a MIDI interface than remove it.

How It Works & Editing

The VL70m utilises Yamaha's proprietary technology, Virtual Acoustics (VA), to make sounds. VA in turn makes use of a technique called physical modelling to produce the sounds — it literally uses a mathematical 'model' of the instrument, and calculates from this what would happen acoustically if you were playing the instrument in real life. As a result, VA sounds can exhibit the characteristics of real‑world instruments, because the sounds are produced from an analysis of how the real instrument works, and not because someone has programmed a synthesis algorithm to try and emulate them. Even the transitions between notes sound real! The disadvantage used to be the huge computing power necessary to make all the calculations, but in the VL70m, a single custom chip does almost all the hard work. And what hard work it is: in a Sample + Synthesis (S+S) synth, this sort of chip might be producing multitimbral sounds with 32‑ or 64‑note polyphony — but in the VL70m, it only produces monophonic sounds.

VA synthesis uses three basic elements: a driver, a resonator, and a modifier .

• The driver is the part that puts energy into the instrument — so it is the bit that you blow, pluck or bow, for example.
• The resonator is the timbre‑shaping part of the instrument — for example, the tube with holes in it, in the case of a woodwind instrument, the body and struts of a stringed instrument, or the tubing and flare of a brass instrument.
• The modifier is a special‑purpose set of effects, which are actually linked to the driver and resonator parts of the model. This includes a harmonic enhancer to change the harmonic structure of the sound, a dynamic filter for producing analogue synth‑type filter sweeps, a 5‑band parametric equaliser to tailor the overall tone, and a special resonator intended to produce a 'woody' type of resonance. You control these elements via a large number of parameters which determine how MIDI values (like velocity or information from a breath controller, pitch or mod wheel) are mapped to the physical model. The control parameters themselves have descriptive names which try to indicate their effect on the sound (some examples are Embouchure, Tonguing, Scream, Growl and Damping).

Two years of work on VA synthesis has improved the repertoire of the Yamaha programmers — the VL70m has a much more cultured and mature‑feeling set of sounds than the ones that I drooled over (or drooled into; breath controllers do that) in the VL1 when I reviewed it. There are two banks of 128 preset ROM sounds: the first is designed for optimal playing via keyboard, whilst the second is aimed at making the most of a breath controller or wind controller. Edited versions of these 256 sounds can be stored in the 64 user RAM memories, but the edits are restricted to the controller settings, and do not allow full user editing of the sounds.

The six custom memories are different. These are used to store sounds which are edited using software on an external Macintosh or IBM PC‑compatible computer (or a Japanese NEC PC 9801/9821). Here the editing allows full access to the individual parameters of the mathematical models themselves. There are a large number of values to change, and making meaningful changes requires considerable knowledge of the physics of musical instruments. Making random changes to parameters either does very little or changes the sound completely. To try and ease users into the editing process, Yamaha provide three pieces of free software:

• The Analogue Editor (Mac only). This provides very simple analogue synth‑type controls for a synth which is anything but analogue!
• The Visual Editor (Mac and PC/Windows). This presents a simplified user interface with pictures of drivers and resonators, as well as context‑sensitive hints on how to further process and control your creations.
• The Expert Editor (Mac only). This gives full control over the finest details of the VA algorithm.

Development of these programs is ongoing, and by the time you read this, the PC/Windows support may be better. The programs should be available from Yamaha dealers who stock the VL70m, or via the Internet. I got them from www.yamaha.co.jp/english/xg/html..., but some of the files are almost 1Mb in size, and will take a long time to download using a 28.8kbps modem. The Mac Visual Editor file exploded from 936K to a 3Mb folder, and all the Mac programs use the MIDI Manager. Not having a PC, I was unable to test the Windows Visual Editor.

If you find FM synths easy to program, editing VA using the Expert Editor may present rather more of an intellectual challenge — but if you found FM hard to grasp, you may prefer to use Visual Editor or Analogue Editor.

Playing & MIDI

There are two different playing modes. The default is called 'Voice' mode, and this is intended for use with other modules, especially non‑XG ones. Each voice has its own effects setting — which means that they are all swamped in reverb and chorus. In the other, 'XL for XG', mode, the VL70m is intended to be used as an additional XG sound source in an XG system. In this mode, editing of sounds in the internal memory bank is not possible, and only one set of effects settings is available.

Although the VL70m is monophonic, it is possible to chain several units together and thus increase the available polyphony, although this affects some of the performance controls you can use, like the monophonic portamento and bottom or top key assignment.

The VL70m uses an extension to Yamaha's XG sound set, called 'VL for XG'. The XG GM super‑set provides extra sounds, effects and editing capability, whilst VL for XG defines lots of additional NRPN controllers (Non‑Registered Parameter Numbers) and uses the Sound Controllers (46to 4AH). Complete GM or XG compatibility are not provided, because VA synthesis is restricted to particular types of sounds — although I can't say I particularly missed having GM's telephone, helicopter and canned applause!

In common with almost all GM‑type instruments these days, there is a Bank Change map showing how to access the variations on the preset sounds using bank change messages. Some of the variations seem rather sparsely populated: I'm not convinced that it is a good idea, for example, to have two banks which are identical except for one saxophone sound.

One peculiar feature is way the MIDI Out socket re‑transmits any MIDI messages which arrive at the MIDI In socket of VL70m, except for those messages which match the channel setting given by the 'Note Filter' parameter. This is intended to make it easy for the VL70m to be used with other modules, but carries the potential for all sorts of MIDI mayhem. The time delay for this 'Out as Thru' socket is about five milliseconds, which might become significant if it is used to drive another module with an equally slow MIDI response time.

Differences

As I spent time with the VL70m, I started to notice the differences between the 'series 2' VLR variant of VA synthesis that it uses, and the original 'series 1' VA synthesis of the VL1 family. The most important difference is that the VL70m only has one sound‑producing element, whereas the VL1 has two — although not all VL1 sounds use the 'dual' mode. This means that some of the subtler VL1 effects are not available on the VL70m, like having portamento on one element and not the other (this feature was used to great effect in the VL1's '50/50' preset sound). More importantly, the depth of detail which is available to the programmer on the VL70m is reduced — so the 'C Flute' sound on the VL70m does not have the same 'chiff' at the start of the notes as the VL1 version, because the VL70m is fully occupied producing the note itself, whereas the VL1 uses two elements: one for the note, the other for the chiff sound.

The underlying sounds in the VL70m are similar to those in the VL1, but not identical, and I suspect that there may be a difference in the sample rate — in certain sounds, some of the aliasing components sounded different on the VL1 and VL70m. The VL1 sounds are richer, more polished and sophisticated, whilst the VL70m has a slightly rougher, harsher feel — presumably the algorithm used is not as complex, and uses less processing power. The two actually complement each other very nicely — the VL1 has a smooth, rounded feel, whilst the VL70m is brighter and thinner.

The built‑in effects processing is also markedly different. The VL70m uses a 24‑bit effects chip which feels and sounds very GM in character: distortion is the first effect in the chain, and this is then followed by either the Variation effect (Reverb, Chorus and Echo, plus miscellaneous effects like rotary speaker and auto‑wah) and then the Reverb and Chorus in parallel; or the Variation, Reverb and Chorus all in parallel. It sounded just a little rough and grainy on the VL70m to my ears — but then I was comparing it to something much more expensive. The VL1 has a 32‑bit effects processor with less options (you can't have distortion and flanging together, for example), but it sounds much cleaner, crisper and smoother — especially the reverb.

The VL70m does not have a disk drive, which means that you have to use an external sequencer to store or load edited sounds via MIDI. But if you use the computer editors, then you don't need a disk drive in the module itself. Given the complexity of the editing process, the six custom memories seem perfectly adequate — none of my exploratory editing produced anything even faintly interesting. I wonder how many VL1 owners have used the user memories for their own custom sounds, rather than merely for edits to the controllers?

Conclusion

Very, very nice. For a price which would buy you an ordinary S+S GM module, the VL70m is an entirely different source of sounds. Words like flexible, versatile, striking, expressive and compelling don't often appear in reviews of synths, but they all apply to VA synthesis (see the 'Sounds' box for more on this). Physical modelling may mark a closing of the retro circle: much of the attraction of analogue synthesizers derives from the combination of the interesting timbres they offer and the expression and degree of control over these sounds that is available from the front panel of an analogue synth. The VL70m offers the same kind of focus on control and personal expression. This is not a module where you listen to the presets and then know everything that it can do — instead, you need to work with it, to coax it into producing your personal sound. Just as a musician can produce a distinctive sound from an real instrument, you can do the same with the music you make with the VL70m: but remember that you will need to invest the time and effort in learning how to use it.