Magazine Archive

Home -> Magazines -> Issues -> Articles in this issue -> View

Sequential's Prophet VS...

The new-wave sound

Article from Sound On Sound, July 1986

...'The first genuinely NEW keyboard since the DX7' proclaims our review. Mixing four different waveforms together in a technique christened 'vector synthesis', Sequential's new baby can create some stunningly different synth sounds. Could it be what the market's looking for? Mark Jenkins reports.

A new model, a new type of sound - a new start for Sequential? Mark Jenkins fills in the details.

A few years ago Yamaha overturned the keyboard world with the launch of the DX7, an instrument so powerful that at first many thought it could only be programmed by a computer. Programming the DX7 still presents problems for many players (147 parameters for each sound can't be sniffed at!), but FM synthesis has certainly made its mark on modern music. The question now is - are we about to see another revolution on a similar scale?

There have been a couple of attempts to create original sound generation systems in the last few years, Korg's Digital Waveform Generation System being one of the most interesting. But most electronic keyboard instruments could still be classified under one of three headings: analogue, sampled, or FM. Sequential had the analogue side of things covered very nicely with the Prophet-5 and 600, and now seem to dominate the pro sampling field with the Prophet 2000.

But of course, Sequential couldn't touch the patented FM synthesis technique (although Yamaha have licensed the system to a couple of computer manufacturers), and so have moved on to something potentially even more exciting - Vector Synthesis.

The Prophet VS takes its name from this system, which simply implies the variable mixing of four waveshapes using a joystick with Up/Down and Left/Right movement. The way in which the joystick mix is altered, manually or automatically, during the course of a note is referred to as a vector.

Although it sounds complex, Vector Synthesis is very easy to use, and the new Prophet's many options are laid out in a tremendously simple and logical way. This definitely is one keyboard you can play about with, without needing to stick your nose in the manual every five minutes.


The VS features a five octave (C-C) velocity and pressure-sensitive keyboard with eight-note polyphony. You can split the keyboard for two four-note polyphonic sounds, or layer it for a dual four-note sound. The velocity sensitivity is fine, but the pressure sensitivity on the model I reviewed was very stiff indeed.

Each of the Prophet's voices has four oscillators (A, B, C and D) which are mixed together with a left-hand joystick. This isn't sprung, but if you return it to the centre position the oscillators all have the same share of the mix. Each oscillator can have any of the 128 available waveshapes, as we'll see.

The VS features a sprung pitch-bend wheel and non-sprung modulation wheel, a 32-digit LCD for displaying sound names and other parameters, a two-digit LED patch number display, and ten Program Select buttons. Most programming is achieved through use of a data entry slider, but parameters are called up with mechanical buttons and there are conventional rotary knobs for Balance and Volume. The VS is very much a stereo instrument and I recommend that you have both rear output sockets connected up whenever possible to make the most of the sounds.

On the right of the main panel there's a slot to load further sounds from a cartridge, and a table of the Source/Destination combinations possible for the modulation functions - not as complex as those on the Oberheim Matrix-6 I might add, but pretty comprehensive. A similarly useful diagram at the top of the panel shows the five-stage envelope for the filter, amplifier or wave mix, plus the points around which the envelopes can loop (again, I'll delve into this later).

The VS filter has simple cut-off, resonance and envelope amount parameters, but its frequency can be modulated in several ways by two LFOs, velocity, pressure and much more, making it a pretty versatile tool.

And just to finish off the mechanics, there's a rear panel Aux jack socket to duplicate the arpeggiator latch function; an Alternate Release jack socket for a footswitch that's usually programmed to give a piano-like sustain; MIDI In, Out and Thru sockets with a switch to select Alternative Out functions on the Thru socket; and audio jack outputs in the form of Left/Mono and Right/Headphones. There's also a small preset to alter the viewing angle of the front panel LCD readout.

The VS holds 100 sounds in its memory, and since each oscillator can have a fixed or moving position in the stereo spread, you may find yourself using the Balance control quite a lot. Single, Split and Dual keyboard modes are available, and you can also use Unison to combine all 32 oscillators on a single note for monster bass sounds! The depth and routing of the velocity and pressure sensitivity and the modulation wheel, can all be programmed for each memory, but the pitch-bend depth can only be programmed up to a musical fifth for the keyboard as a whole.


One interesting facet of the VS is the built-in arpeggiator, which can play on quite unaffected by the pitch-bender if you 'latch' a series of notes. Why Sequential don't just go for a built-in sequencer is totally obscure, because their arpeggiator falls just short of being one. It offers a whole host of features including:

Footswitch-operable latching
Sequence storage during power-off
Programmable rate
External MIDI clock sync
Live overdubbing up to 120 notes
Variable Scan (Up, Down, Up/Down, Assign, Reverse and Random)
One to five octave range
One-note to four-note selectable repeat
Play of either or both sides of a split
Switchable velocity response
Second arpeggio layering
Selectable rest insertion using top C
Selectable clock rates.

And the first person to use all of these together is the winner!

Arpeggiators and such like are not the exclusive province of the Prophet VS though. What is unique to the VS is the effect of varying the wave mix joystick while playing, the depth of effect depending very much on the make-up of the individual sound. In fact, the VS does have one obvious forebear - the PPG Wave. The PPG stores waveforms in digital memory (as does the VS) but rather than mixing between a set of waveforms, it creates a long 'wavetable' and scans down the table during the course of a note. The smoothness or randomness of the table determines the basics of the sound, and some very 'jagged' metallic effects can be created.

Frustrated PPG lovers will be pleased to learn that the VS has a vast repertoire of Wave-like sounds. Most of its effects are smooth though, so calculated transitions are hard to programme. But it is possible to vary the wave mix in a completely random way using the LFOs or to set a pattern of sudden wave mix changes using the envelope generators, so there's plenty of scope.


Let's look at the Prophet's oscillator waveforms in more detail.

Each oscillator has 96 basic waveforms including White Noise, plus 32 waveforms you can programme yourself. As on the PPG, the actual nature of these waves is a mystery - you just have to choose them by ear. Your own sounds can be dumped to RAM and can use any of these programmable waves; ROM sounds supplied by Sequential will only use the 96 basic waves. A RAM cartridge holds 100 programs and 32 waveforms, and is likely to cost over £80.


Calling up a sound is easy, and if you want to change it, simply hit 'Program Edit' and the desired parameter button and the LCD display allows you to alter values with the data entry slider (á la DX7). The parameter buttons scroll through their various options simply by pushing them repeatedly - so you hit 'Oscillator Select' once to edit some aspect of Oscillator A, again for B, and soon.

The 'Review' function allows you to check your original sound before committing yourself to a change, and each program can be named with letters being called up using the data entry slider. Recently a few computer packages such as 'DX-Droid' and Steinberg's 'Pro-Creator' have been launched to create alternative sound settings on the DX7, but the Prophet VS has gone one better with its own 'Program Creation' function which assigns random values to every parameter - from mixer envelope to program name. I didn't have time to try this one out thoroughly, but as Sequential state, it's a very good way of avoiding 'programmer's block' even if only one program in ten turns into something useful.

Now on to the Link function, which allows you to set up a connection between two programs for Split or Dual modes. Hitting 'Link Select' while you're working on one program gives you an opportunity to choose another sound, and you can set a delay of up to 500ms between the original and linked programs to create ADT, echo or cascading effects.

If your linked sounds are in Double mode, you can mix between them using velocity or pressure sensitivity by applying positive modulation to one and negative modulation to the other. Velocity and pressure can also affect the wave mix, so let's take a look at how waves are mixed on the VS.


As Sequential point out, the Vector Synthesis method allows you to perform more of your synthesis at the waveform stage and perhaps less with the filter. As you move the VS joystick, the proportions of the four oscillators in a voice are altered, with 100% for each of the oscillators at the North, South, East and West settings and 25% each at the centre position. Each oscillator can have a complex waveshape, so the combination of the four is very complex indeed. And as you move the joystick, the LCD readout shows a percentage value for the volume of each oscillator.

You can also move the mix point along one axis or the other using an LFO, keyboard velocity or pressure, and along both axes with an envelope. Some of the changes produced are pretty unpredictable, so the VS appears better at coming up with totally new sounds rather than imitative effects. Having said that, there are very impressive string, brass, piano, organ and metallic patches in the basic presets.

'Oscillator Select A-D' calls up an oscillator for editing, along with its wave number from 0-127 (with 126 as silence and 127 as White Noise). In addition, coarse and fine frequency can be chosen. As on the DX7's Initialise mode, you can select a basic organ-like patch for easy editing.

Now on to those five-stage envelopes for filter, wave mix and amplifier. As far as the wave mix envelope goes, moving the joystick to a new position allows you to programme that position as the destination for one stage of the envelope. The first three sections of the envelope are covered while a key is held down, and the fourth (in its standard or Alternate Release versions) is covered after the key is released. Envelope points are numbered 0,1,2,3, and 4, and you can set up a loop from points 3 to 0, 3 to 1 or 3 to 2; the loop can be forward-only or backward and forward, and the preset sounds incorporate some crazy repeat, echo and warbling effects to demonstrate its use.

That right-hand modulation routing table isn't as complex as it seems, since as I mentioned you can step along your parameter options just by repeatedly hitting a parameter button. 'Modulation Source' offers you LFO 1, LFO 2, Pressure, Velocity, Keyboard, Filter Envelope and Mod Wheel, whilst 'Modulation Destination' offers Frequency, Filter, Mix, LFO 1, LFO 2, Amplifier, Pan and Chorus - and each available combination can be turned on or off completely. Some combinations aren't available - you can't modulate LFO 2 with LFO 2, for instance.

There are a few other performance features such as Glide, Voice Pan and Panning Modulation, which enable you to set up panning voices and wave effects to create a very complex stereo spread indeed. The 'Filmusic' preset patch is so complex that it's virtually a soundtrack in itself!

To get into the VS most fully, you'll want to create your own waveforms, which is done by punching 'Edit Waveform' to call up a new set of rules for the controls. The joystick is then used in conjunction with the oscillator fine tune controls, which become harmonic generators, to step each waveform along to its next harmonic. Your finished waveform can then be saved internally or to a RAM cartridge.


Typically for Sequential, the Prophet VS MIDI spec is highly advanced, including program select, patch change, MIDI clock for the arpeggiator, MIDI channel split, arpeggiator channel, MIDI control of left or right sound only, program or wave data dump to a computer and standard sample data dump - although assuming you can dump a sound from a MIDI Fairlight into the VS may be optimistic, to say the least.

MIDI Single mode allows each VS voice to respond to a different MIDI channel but doesn't give you multi-timbral playing, which is a shame; it does enhance glide effects and other performance parameters over MIDI though. The VS also has an Overflow mode, so that any notes over and above the built-in eight voices can be passed on to another synth for 16-voice playing.


As for the sounds of the VS, they're truly something else! The machine is quite capable of producing Prophet-5 type twangs and dense, lush strings, or screaming lead lines. But it also covers most of the PPG Wave's repertoire of metallic, digital sounds, plus a good deal of DX7-like programs, and a whole stack of noises which are indescribable. The basic common denominator is 'richness' - there's always a lot going on, particularly if you use the two-channel chorus and stereo outputs.


It's important for Sequential that the VS offers a lot of new sounds, because cliched synth sounds are the one thing that could kill off interest in the industry. It's also important that the VS is easy to use, and an obviously high-quality instrument. Thankfully, it fulfils all of these counts.

The VS is definitely the most exciting keyboard launched since the DX7 - of course, the Ensoniq Mirage is exciting because it's cheap, but the Prophet VS is (relatively) cheap at £1895 inc VAT, and more importantly it's something genuinely NEW!

As a studio or stage instrument the VS has a great future, and in combination with a sampler like the Prophet 2000 or 2002, it would provide almost everything the modern keyboard player needs. Sequential seem to be undergoing a revival of late, and it's nothing to do with the economic climate - it's everything to do with top-class, imaginative products like the Prophet VS.

Thanks to Rod Argent's Keyboards, 20 Denmark Street, London WC2 (Tel. 01-379 6690) for demo facilities.

(Contact Details)

Also featuring gear in this article

Previous Article in this issue

AHB Keymix

Next article in this issue

Patching Up

Publisher: Sound On Sound - SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...


Sound On Sound - Jul 1986

Donated by: Gavin Livingstone

Review by Mark Jenkins

Previous article in this issue:

> AHB Keymix

Next article in this issue:

> Patching Up

Help Support The Things You Love

mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.

If you value this resource, you can support this project - it really helps!

Donations for June 2024
Issues donated this month: 0

New issues that have been donated or scanned for us this month.

Funds donated this month: £0.00

All donations and support are gratefully appreciated - thank you.

Magazines Needed - Can You Help?

Do you have any of these magazine issues?

> See all issues we need

If so, and you can donate, lend or scan them to help complete our archive, please get in touch via the Contribute page - thanks!

If you're enjoying the site, please consider supporting me to help build this archive...

...with a one time Donation, or a recurring Donation of just £2 a month. It really helps - thank you!

Small Print

Terms of usePrivacy