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It's Cee Zee (Part 2)

Part Two of our two-part Programmer's Guide To The Casio CZ range of synthesizers catches Phil South explaining the nuts and bolts of sound modification, with tips and hints on how to approach the creation of your own PD sounds.


In this final part of our Programmer's Guide To The Casio CZ range, Phil South takes us one step closer to sonic paradise.

Once more into the RAM slot, dear friends. Yes, it's the second part of this in-depth guide to the care and feeding of your Casio CZ synthesizers, and in this thrill-packed sequel we'll be covering all the bits and bobs of how to programme, sequence and generally cope with these powerful, yet inexpensive synthesizers.

Last month we looked at the differences and similarities between the CZ, analogue and FM synths; asked what Phase Distortion is and answered ourselves; dabbled in a bit of geometry and physics; had a look at the control panel to see what we've got to work with and generally laid the ground work for this month's tome. Now that you're suitably genned up on the basics, it's now time for a little application, ie. some hands-on experience at programming a sound to do what you want it to; plus more on how to use the different parameters; some MIDI information; a word or two about CZ Library Editors and, finally, some patches for you to have, free-of-charge (go on, take 'em!), from my own private stock in our "but here's one I made earlier" department.

A NEW LEAF



And it's not even Autumn yet! Before we start, let's initialise a voice for us to doodle around with. Hold down the INITIALISE button and then press all the grey buttons in the parameter section, each in turn. This gives us a preparatory patch, producing a reasonably pure basic tone for us to work from. Now in order to start you off, and give me something to hang my explanations on, let's follow through the programming of one or two of my favourite sounds.

All the incremental data entry, or parameter twiddling, is done with the Up, Down, Left and Right cursor keys. So, in constructing our sound from this musically blank patch, the place to start is with DCO1, the primary digital oscillator.

When you press the DCO1 key, the words WAVEFORM and FIRST=1 SECOND=0 appear in the LCD window. When combining two waveforms on either of the oscillators, whereas you can select any of the eight possible waves on FIRST, you can only select 1-5 on SECOND. There is a technical reason for this making it difficult to bash two resonant waveforms together. The reason being that in order to combine two waveshapes, they're sampled from the waveform tables in ROM and played by the oscillator alternately and very quickly (see Figure D) so that they blur together. It just doesn't work with harmonically resonant waveshapes, so the designers of the machine have saved you the heartache of finding this out and made it physically impossible.

FIGURE D.

So having selected the wave, or combination of waves, that approximates the fundamental tone of the sound you're looking for, you're ready to treat and move the sound. Incidentally, it's a good strategy to use LINE SELECT to step through the different combinations of the two oscillators (all four of them) in order to hear the separate elements alone and together. One of the biggest mistakes you can make when programming a synth of this kind is to try and bash the waveshapes together randomly and see what you can hear. Although this kind of experimentation has its place, it is advisable to keep as many elements of the sound separate in your mind (and on paper) and combine them intelligently and deliberately.

In the case of our first sound, 'Piano 1', we are looking to create a metallic sound, like a string being hammered. We want to combine a couple of thin sounds, but one with a bit more strength or body. The thin quality of the pulse wave, with its strong fundamental, sounds promising but it needs something... perhaps the similar but more full-bodied sawtooth. So let's make DCO1 FIRST=1 and SECOND=3. It still needs something extra, perhaps another thin sound to phase with the pulse wave, and something else to fatten it out and make it a little more 'woody'. So make DCO2 FIRST=2, a square wave, and SECOND=3. The two pulse waves in the two oscillators will interact, giving you a slightly altered timbre with each key press. There we have it, the basic waveforms which we will now proceed to treat.

RATE & LEVEL



There are three envelopes you need to shape your sound: the Pitch, Timbre and Volume envelopes, ie. DCO ENV, DCW ENV, and DCA ENV. I have this theory that it's purely these envelopes that prevent most people from understanding and experiencing their CZ in a wholly meaningful and thoroughly West Coast fashion. It's one thing to twiddle a knob on an analogue synth and hear the shape, but because you have to digitally increment the envelope generators on a CZ it naturally forces you to try and visualise the sound envelope. It's exceedingly difficult to do this in your head, so it's always best to sketch out the kind of envelope shape you want and programme from that. If you can't use some kind of Library Editor program to alter the envelopes graphically on your computer (more about these later), then drawing out what you expect from the sound you're aiming at is enormously beneficial.

Some people have expressed confusion over how the CZ's RATE/LEVEL envelope works, so let me quickly recap.

FIGURE E.


For the Pitch, Timbre and Volume envelopes, the CZ uses a system where each of up to eight stages of the envelope are specified by just two figures - a LEVEL and a RATE, ie. the speed at which the change takes place between the previous LEVEL and the new programmed LEVEL. (See Figure E.) This is a very flexible method of creating envelopes, but due to this problem of visualising the trajectory of the envelope, it can be a little troublesome. But it's important to understand the way they work and how they can be used.

The Pitch envelope can be effective when used to place a fast pulse of pitch bend at the beginning of a sound, like a piano for instance. The initial action of the hammer hitting the piano string or tone bar causes just the tiniest bending of the string or bar, changing the pitch momentarily and giving that small atonal 'boing' at the front of the sound. This is as important a characteristic of the sound as the use of a sawtooth/pulse teamed with the square wave/pulse, to give it that basic metallic stringy quality.

So the Pitch envelope for our 'Piano 1' patch would be as follows:

FIGURE F.

As you can see, the Pitch envelope for the second DCO is slightly flatter than that of DCO1, bringing a tiny element of delay into effect. Let's face it, in a piano sound we need to imitate as many resonant surfaces as we can.

(In the selection of an envelope the ear does play a part, of course it does, but really you ought to start from somewhere close to where you want to end up; a value of 99 being fast, 45 being medium and 00 being slow. Then you can fine tune it to the position that sounds best, and you can play without your dog howling along!)

KEY FOLLOW



The DCW is the digital equivalent of the old analogue 'filter'. On the CZ range the DCW can be modified by an envelope to change the timbre (pronounced 'tam-brr') of the sound by filtering out certain frequencies as the note plays. As it has eight stages, like the other two envelopes, it is quite flexible in what it can do with the sound. For example, you can 'wow' and 'waa' the sound, imitating the once popular guitar effects pedal, taking the level of the envelope up and down in steadily decreasing amounts. Okay, so that sounds horribly dated, but the point is you could do it if you wanted.

The other very interesting parameter that comes into play at this point is the KEY FOLLOW number. KEY FOLLOW does one of two things depending on whether you apply it in the DCW or DCA of an oscillator. In the DCW it means that as you move further up the keyboard, more and more of the high frequencies are removed, making the sound less and less bright. This can be handy if the sound is fairly shrill anyway and playing it at the top end sets your teeth on edge. It just gives you a broader playing range for certain, otherwise unlistenable, sounds.

When applied to the DCA, KEY FOLLOW alters the duration of the sound, making it shorter as you progress up the keyboard (as per a sound sample). Both of these effects can add a certain 'organic' quality to a sound, especially when imitating an acoustic instrument whose tonal character changes in this same way, like a piano for instance.

In this light, let's give the sound a nice flat dose of KEY FOLLOW, with a setting of 9 on DCW1, 1 on DCW2, 4 on DCA1 and 0 on DCA2, and add to this the following DCW settings:

FIGURE G.

Now things are really beginning to shape up. Playing the sound, you can begin to hear the piano-like quality beginning to rise from the rude tone we began with. The Amplifier envelope is percussive, but with a low Sustain level, imitating the striking of a note and the sustain of the sound reverberating through the sounding board, but quite softly.

And finally, to shape the last element of the sound, the amplifiers DCA1 and DCA2, we require pretty much the same kind of envelope as we used for the DCWs - a sharp peak, higher in level this time, terminating in a long but low sustain. (See Figure H.) So now, having shaped our sound, given it a basic bunch of waveforms and enveloped the pitch, timbre and volume, we can start to add some effects to it.

FIGURE H.

To give it a slightly 'flanged' feeling, we can use the DETUNE function to offset the tuning of DCO1 and DCO2 by an infinitesimal amount. So, ignoring the OCTAVE and NOTE parts of the DETUNE mode, we must set the FINE tuning to 1, giving us a narrow flange. Compare the sound with and without this setting to hear how much better it sounds with it implemented.

Now all that remains is to set the OCTAVE to 1. (This sound doesn't need any VIBRATO. When did you last hear a vibrato piano? Ugh!) Et voila! Deep fried piano sound. This sound is at its best in the lower registers, so it might be a good idea to experiment with the OCTAVE switch, depending on what you intend playing.

Try feeding it through a reverb unit and you'll see that although it's not as good as the piano sounds you can get using FM synths, it is a good bog-standard piano-like timbre with enough roundness of tone to be melodic and enough punch to be rhythmic. You'll notice that this sound doesn't use RING modulation, NOISE or VIBRATO. Don't worry, I'm coming to that, but before I do I'd like to re-discuss DETUNE for a minute.

WHO CALLS DETUNE?



DETUNE is an interesting feature because not only can you use it to effect the sound in ways like adding flanging and phasing, but you can also do the FM trick of accentuating certain harmonics of a pitch!

The FINE function, as we've seen, allows control over small differences in pitch which change the quality of the sound rather than the harmonic content. NOTE gives you the ability to offset the two oscillators in semitone steps, like so:

INTERVAL NOTE
Unison 00
Minor 2nd 01
Major 2nd 02
Minor 3rd 03
Major 3rd 04
Perfect 4th 05
Diminished 5th 06
Perfect 5th 07
Minor 6th 08
Major 6th 09
Minor 7th 10
Major 7th 11
Octave 12

The last DETUNE parameter is OCTAVE, which alters the detune between the oscillators in octave steps. But the fun starts when you balance NOTE and OCTAVE together. In this way you can adjust the pitch offset so that it is exactly the right multiple of the fundamental frequency to make the harmonics sing out. To get the first ten harmonics out of a sound, you have to set the following NOTE and OCTAVE numbers:

HARMONIC NOTE OCTAVE
1 00 0
2 00 +1
3 07 +1
4 00 +2
5 04 +2
6 07 +2
7 10 +2
8 00 +3
9 02 +3
10 03 +3

Pretty sophisticated stuff, eh? After the first ten harmonics, the rest are quite hard to find, but two which are quite easy are the 16th harmonic (00, +4) and the 32nd (00, +5). Have a dabble around with some settings anyway and see what you come up with.

RING MODULATION



The remaining effects which we haven't touched on can be explained best by looking at another sound. In this next example, we want to programme a slap bass sound in the Mark King mould. I could have done the obvious thing and opted for a bell-like tone as our example, but I'm not an obvious kind of guy! And besides, the bell effect of ring modulation is well documented, while it's facility to tone down a sound is not, especially with relation to the CZ synths.

The best way to see what's happening here is to listen to the sound without RING and then with it. The slap bass is basically a very simple sound on one oscillator, with a double sine waveform for the high harmonics, along with a square wave to give the feeling of resonant wood. The DCA envelope is a straight on/off affair, but with a little rounded attack and decay added so that it doesn't just sound like a Bontempi organ! The discordant harmonics of the sound originate primarily from the DETUNE setting: +3 OCTAVE, 10 NOTE and 54 FINE. But, strangely, the ring modulation is aligning the odd harmonics (1, 3, 5 etc), rather than adding more strident and discordant ones! This is an effect better heard than explained, so I urge you to try it on your own synth.

In the CZs, the ring and noise modulation effects are only available when using two oscillators, due to the way the effect is made, electronically combining them to produce a multiplied wave, riddled with non-integer, atonal harmonics. One area where atonal harmonics really come into their own are guitar sounds, particularly distorted guitar sounds. Try it and see.

Table 1
(Click image for higher resolution version)


MULTI-TALENTED



Where Casio's CZ synths can really take the limelight is as part of a MIDI controlled music system. It's a little known fact but the CZ synths are among the most MIDI-compatible instruments around! But even less widely recognised is the way that they can be used as multitimbral MIDI sound sources in a computer sequenced set-up of the kind that has recently become very hip. The heart of such a system is typically one of the cheap home computers, like a Commodore 64, Spectrum (huh?), Atari ST (or even a Macintosh). Then, cascading off it, you have the multitimbral expander devices like the TX81Z or FB01, and your MIDI drum box, and you sequence them all to produce a live track with a great many voices and sounds. But it's possible to have a four-voice multitimbral device by using your Casio CZ.

FIGURE J.

All you need do is set up your CZ so that it operates in Mono Mode, and you can assign a different patch to a different MIDI channel (see Figure J). Then you can play four monophonic voices and sequence them all together. You could probably pick up two inexpensive CZ101's secondhand, which would give you eight voices! It's worth thinking about.

SSSSHHHH!



Why are we whispering? Oh, this is the bit about Library Editors, is it? Yes, by far the best way of programming your CZ is via a MIDI box and a computer using one of the many and varied Library Editors on the market. These are available for all the popular computers. They are a good idea for several reasons: they allow you to programme the envelopes, for example, and see the shape of them on-screen as you do so; you can store many banks of patches on one floppy disk (or in the Spectrum's case, on tape) and that means no fiddling around with (costly) RAM cartridges. They're not too dear either, with the cheapest being about £25 and the most expensive £140. Here's a quick round-up of what's available, so you can pick out the one for your particular computer.

HYBRID ARTS produce a handy program for the Atari ST called CZ-Android which includes a Numeric Editor (for tapping in numbers as you would on the synth), a Graphic Editor (where you can move the sounds around using the Atari's mouse) and a Patch Librarian, so you can store your sounds. It costs £89.95 and you can buy it from Syndromic Music ((Contact Details))

DR.T make a similar item, also for the Atari, in line with their excellent sequencing software, called the CZ Keyboard and FX Editor. This is a good quality package and if you already use a Dr T sequencer it might be worth getting this one, although it is slightly more expensive at £99. Available through Take Note ((Contact Details)).

OPCODE specialise in music software for the Apple Macintosh, and in the same series as their Midimac Sequencer you can now buy their Library Editor for the CZ synths. Cost: £139 pounds and also available through Take Note. Okay, so it's a trifle expensive, but if you have bought a Mac with a MIDI interface you can probably afford it.

JORETH's CZ Tone Editor works on the Commodore 64. Much the same sort of thing as the others but the major difference being that this was one of, if not the, first. It has an interesting side function where you can play a piece of music continuously while altering the CZ parameters, so you hear the changes as you make them. Superb value at only £44.95 from Joreth Music ((Contact Details)).

XRI SYSTEMS have an Editor which features the graphics and editing facilities of the other packages, but works on a humble Spectrum computer. Includes a free start-up library of 96 new sounds on cassette, ready to load. Only drawback is tape storage. But it is the cheapest way into this method of working. Just £22.95 from XRI Systems ((Contact Details)).

FINAL WORDS



To sum up, the key to programming your own sounds on CZ synths is planning. If you know the sort of sound you want before you start altering parameters, and you've drawn sketches of the envelopes you require, it's a piece of cake to imitate any natural sound or invent an original synthetic timbre. So plan carefully and you can't go wrong. Okay, so every synth has its own sound, and certain synths are good for certain jobs. The CZ has a warm, Moog-like sound, most un-digital in aspect, and as such can add many individual sonic textures to your sound.

Incidentally, I'm always interested in new CZ patches, so if as a result of these articles anyone comes up with some real corkers, then I'll be happy to receive them. Just send the patch sheet to me c/o Sound On Sound. Happy programming!



Previous Article in this issue

The Magic of Daniel Lanois

Next article in this issue

Soundbits Voice Master


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

 

Sound On Sound - Aug 1987

Topic:

Synthesis & Sound Design


Series:

Programmer's Guide to the Casio CZ

Part 1 | Part 2 (Viewing)


Feature by Phil South

Previous article in this issue:

> The Magic of Daniel Lanois

Next article in this issue:

> Soundbits Voice Master


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