iPD Digital Synthesiser
Casio's latest synthesiser employs the successor to the company's own PD synthesis system - interactive Phase Distortion. Bob O'Donnell investigates a new phase in synthesis.
Big sounds, a new approach to FM and a built-in graphic display are all standard on Casio's latest "Z-series" synth.
BACK IN 1985, when Casio launched their CZ101, they managed to convince a lot of people that the Phase Distortion (PD) synthesis found on the CZ series of instruments was fairly similar to old-fashioned analogue principles. For example, the Digitally Controlled Wave (DCW) parameter that gave the impression of opening and closing a filter actually adjusted the modulation amount of a "control" oscillator - just like a modulator in FM. But by using familiar terms they avoided the confusion that Yamaha ran into with FM technology. They managed to disguise the wolf of digital synthesis in the sheep's analogue clothing. The truth of the matter remains that Phase Distortion is actually a variation of FM.
All this makes Casio's announcement of a new instrument utilising a technology called interactive Phase Distortion (iPD) - which even more closely resembles FM - a bit less surprising. The VZ1 is not a DX7 clone, however - let's make that clear from the start - though it does share some basic principles and sonic characteristics with DX instruments. It also maintains several of the features found on the original CZ series, and adds many advanced capabilities of its own.
BASICS FIRST: THE VZ1 is a 16-voice, multitimbral synthesiser with a 61-key velocity and pressure-sensitive keyboard. For better or worse, there are no samples, effects or sequencer built in - this is a synthesiser, pure and simple (or complex, in the VZ's case). The rear panel features two independent audio outputs and a single mix output, the usual complement of MIDI In, Out and Thru jacks and a handy little MIDI on/off switch (which, curiously enough, turns the transmission and reception of MIDI data on or off). Other connections include a headphone jack, and inputs dedicated to a sustain pedal, a volume pedal, a footswitch for stepping through programs, and a programmable footpedal - or "foot variable resistor", as Casio call it.
The front panel is where things get interesting. Off to the left are three performance wheels - the first is dedicated to pitch-bend and the other two may control a variety of different effects that are programmed per patch. The middle control is suited to modulation and hence has no spring detent but the third wheel is spring-loaded and returns to its original bottom position when released.
The VZ1 features internal memory for 64 normal patches and 64 "Operation Memories". These allow you to combine up to four different patches in any configuration of splits or layers you like. In addition, the VZ1 comes with a ROM card which holds 128 more of each type of patch. Sliding the card into the slot on the instrument's back panel, gives you immediate access to an impressive 192 patches and Operation Memories (RAM cards which can hold 64 of each are also available). The VZ10M, a 3U-high rackmount version of the instrument, offers similar facilities, but adds an XLR mixed audio output for studio use.
THE VZ1 IS divided into four basic modes of operation: Operation Memory, Normal, Combination and Multi Channel. The first two correspond to the types of patches stored in the VZ's memory. To play either of those types you enter that mode by hitting the appropriate button, and select from what's available. When you want to edit normal patches you enter the Menu sub-mode by hitting one of the three Menu buttons - each one is dedicated to a particular set of parameters - and proceed to the appropriate software page on the display. Easy enough. Things aren't quite as simple with Operation Memories, however, because they can only be edited in the Combination mode - which is really nothing more than a working edit buffer. Unfortunately, you have to first write the Operation Memory you want to edit into the Combination mode - it won't appear there automatically. It's not a big deal to go through the extra step, but I don't understand why the Operation Memory mode couldn't have had its own edit sub-mode.
Moving on, the Multi Channel mode is for creating one multitimbral setup for the VZ1 when it is to be used in conjunction with a sequencer. (Just one?) The VZ1 can operate on up to eight MIDI channels at a time, playing eight different timbres. Each part, or Area, can be assigned one normal patch, have its own fixed polyphony (there's no dynamic allocation), its own output level and its own MIDI channel. In addition, the tuning of each patch can be set per Area (over an amazing 10-octave range) so that you can recreate some of the detunings used when combining patches into Operation Memories. As for outputs, Areas 1-4 are all hardwired to output 1 and 5-8 are hardwired to output 2. On the MIDI and performance side of things, each Area can be programmed to respond individually to solo mode and portamento parameters, as well as pitch-bend, aftertouch, the two definable controller wheels and the footpedal.
NOW FOR THE fun stuff. The VZ1 derives its distinctive sound from an iPD sound generation system. With it, you control eight modules - each of which consists of a Digitally Controlled Oscillator (DCO) and a Digitally Controlled Amplifier (DCA). One of the reasons that the VZ sounds as big as it does is because it offers a choice of eight different waveforms for each of the oscillators. In addition to FM's usual sine wave, there are five different sawtooth waveforms with increasing amounts of harmonics and two noise waveforms (one with a fundamental frequency that will track the keyboard, and one that's just plain noise.) By accessing Menu 1 (voice editing menu) each of the DCOs can be tuned over a theoretical 10-octave range and either track the keyboard or remain at a fixed pitch.
Theoretical because both the high end and low end of the range cannot be accurately produced by the VZ1 - which makes me wonder why offer that large a range in the first place? On the high end, in particular, the VZ1 ends up producing all sorts of strange alias-like noises and warbles. On the positive side, included in the tuning functions of the DCOs is a Harmonic parameter, which will instantly set the musical interval defined by the selected harmonic. This is just like FM's Ratios. It can be set over a range from 1:63 (1/63) to 63:1.
The DCA portion of each of the eight modules per patch has an eight-stage rate and level envelope generator - true to Casio tradition - which differs from previous Casio envelopes in that the Level amount of the end point is not automatically set to zero: as on the DX7, the "release" level can have a positive value to produce drones or to increase the modulation amount when a note is released. A single eight-stage pitch envelope is also available to globally affect all eight modules.
Once you've created a sound you like, the VZ allows you to do a great deal of room to tweak it into a performance-ready patch. First off, each of the nine EGs in a patch (eight modular DCAs and one global DCO) has a depth control to determine the overall level of the envelope. In addition, the rates and levels of all EGs can be affected independently by user-definable, six-point Key Follow curves as well as by velocity. In other words, the keyboard position of the note you play and the strength with which you play it can alter any envelope's shape - either by moving the levels up and down, making the rates longer and shorter, or probably a combination of the two. You can program a single six-point Key Follow curve which globally affects the overall rate of any of the nine EGs and program nine independent six-point curves to affect the overall level of any single EG.
In addition, you can choose from eight different velocity curves (16 if you include inverting them) and 32 sensitivity amounts for each EG to control how velocity affects its overall level. Finally, you can select one curve to affect the rate of all the EGs - in which case the VZ1 allows you to select which step(s) of each EG you want to be affected. For example, you could have velocity affecting the attack and release segments of the pitch envelope and the first four segments of the DCA envelope in module 3. This is definitely one of the instrument's finest points.
Other parameters available per patch include an octave function and independent global settings for vibrato and tremolo - including a choice of four waveforms, rate, depth, delay and multi (key sync) controls. Finally there's an amplitude sensitivity setting per module, which determines how strongly the modules will be affected by tremolo or amplitude envelope bias.
Vibrato and tremolo rate and depth, positive or negative pitch-bend, portamento time and the aforementioned amplitude envelope bias (which affects the overall level of selected modules) can all be controlled independently by aftertouch, the two definable wheels, and the footpedal. These routings may be defined per patch. The pitch-bend range is four octaves in either direction and if you use it at this extreme, you can get some slowed down sample-like effects.
On the MIDI front, the VZ1 permits you to transmit any MIDI controller from 12-31 with the second definable wheel. In addition, MIDI volume transmission can be enabled or disabled and you can initiate SysEx dumps from the front panel - a big improvement over previous Casio synths.
Once you've got some individual patches you like, you can put up to four of them together in Combination mode (though polyphony will be reduced to four notes). As with the Multi Channel mode, each patch can have independent pitch, and level amounts, and can respond independently to solo, portamento, pitch-bend, aftertouch, definable wheel and footpedal settings. In addition, individual patches can be set to respond to or ignore sustain pedal messages. Most importantly, patches can be grouped together in eight different keyboard assign modes, with various combinations of splits and layers. Up to three independent split points can be set. If you'd prefer not to have hard splits, you can use the VZ1's impressive positional crossfade function to smoothly spread out the various patches.
If you're working with a layered patch, you can set up to four different velocity splits, with user-definable velocity ranges. You can also invert the velocity response of any patch for velocity crossfades, and delay each patch independently. Finally, you can invert the vibrato and tremolo effects independently per patch.
CASIO HAVE USED the "manual on the panel" approach with the VZ1 and, as a result, I initially found the front panel to be a little busy. I have to admit, however, that it does come in handy once you become more familiar with the machine and its operation.
What I didn't find particularly handy was the way you move through parameters. Once you select one of the Menu buttons for editing you can scroll through the various functions, but to edit any parameter nested within those functions you have to hit the appropriate Menu button a second time. When I first started using the machine, as soon as I reached the desired page, I instinctively started using the cursor and value buttons to make adjustments. By doing so, I ended up on a different page. I did get better at it, but it's not what I'd call intuitive.
I'm willing to overlook this small problem, however, because of the helpful nature of the VZ1's graphic display. In the middle of the front panel is a large (64X96 dot), backlit LCD - similar to the one on Casio's FZ samplers. By hitting Display when on the appropriate pages (envelopes, key follow curves, velocity curves, positional crossfades and so on) a graphic representation of the numbers that are usually present will appear on the screen. And yes, you can edit the envelopes while in this display mode and instantly see the results. You can also zoom in and out to one of several different viewing levels for fine tuning. I find this kind of system much easier to work with than a series of numbers - though even the VZ1's numeric pages are neatly laid out and easy to understand.
Another helpful graphic on the VZ1 is available by pressing Line. Whenever you're programming or editing a patch, you're going to want to constantly refer to the overall combinations of the various modules and by holding down this button the VZ1 will display the complete Line configuration. As soon as you release it, you're back to where you were.
Casio have also speeded up the editing process by offering eight individual module select and module on/off buttons (they double as the patch select buttons), and comprehensive copying and initialising functions. If you're working with a function that can be independently set for each module, jumping from one module to another can be easily accomplished by hitting the appropriate button. Also, if you want only to hear a few modules at a time when building or editing a patch, the on/off buttons are invaluable.
Last, but definitely not least, in case you do get confused, the VZ1 actually has a decent owner's manual with a complete function index and helpful tutorials. I would have liked more information on applications of the various functions, but the unique presentation of the index deserves high marks. To give you an idea, the DCO Envelope page in the index lists and explains all the parameters and their range of values, explains what Operating System buttons need to be pressed to reach it, points out that three software pages are dedicated to the function, that graphic editing is available, and that the function affects all eight modules globally, and finally, lists any related functions.
THE FIRST THING you notice about the VZ1's sound is that it's big. With the possibility of having up to 32 sawtooth waves at once in an Operation Memory I suppose that's not a huge surprise, but nevertheless it's one of the instrument's most endearing traits. The multi-waveform modulation also allows it to produce some nasty, biting sounds. It's also capable of producing some useful electric piano and bell patches, but the VZ1 sounds a bit warmer to my ears than other FM synths. The noise waveforms also enable it to produce some fashionable, complex "airy" sounds. I don't think it's particularly well-suited to imitative synthesis, but the synth sounds are great.
To get an idea of the variety, there's no better place to look than the factory presets. Many normal patches work well on their own, but the really good stuff comes from the Operation Memories. The appropriately titled 'See God', as well as 'VZ EP', 'Ice Horns', and 'Headbanger' give a good idea of the VZ1's sound capabilities. What they might also demonstrate if you listen closely enough, unfortunately, is a small noise problem the VZ1 suffers from. It's nothing terminal, but you can hear the noise floor cut in when playing softly and it continues for about a half second after key release. I don't know why, but it seems that lately just about every synth I've heard has been slightly noisy - I hope it's not a trend.
ON THE WHOLE the VZ1 sounds good and is capable of producing a wide variety of different timbres. The iPD synthesis system offers familiar ground to FM users, but is appreciably more flexible. In addition, the small details of the voice structure and the numerous options for combinations make it a very musical instrument.
I can't say enough about the value of the VZ1's display. I realise displays are expensive, but I wish other manufacturers would follow the lead that Casio and Kawai (on their K5) have set. Although the VZ1's graphics are no substitute for a computer and editing software, they are a huge improvement over other synths' LCDs.
Casio have a valuable new instrument in the VZ1. If you don't need a synth with a built-in sequencer or effects, and don't mind spending some time learning another new synthesis system, check it out. It'll be well worth the time spent.
Prices VZ1, £1299; VZ10M, £899; RC110 ROM card £49.95; RAM card, £39.95.
More from Casio Electronics Ltd, (Contact Details)
Review by Bob O'Donnell
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