Subject: Taurus Patch Programming #7
Date: Thu, 22 Jan 1998 21:58:52 -0800
From: timkoelm@iconz.co.nz
To: jv1080@emccta.com

Greetings JV/XP'ers!

Welcome to this week's patch programming presentation and mini-tutorial.

I got a couple o' ripping leads to share with you today. Lead synth programming is one
of my favourite hobbies, and it's a mini art in itself. As well a having to program a
sound with bite and punch, you have to take advantage of a synth's modulation abilities
to tailor the sound to the player. Today, I'll show you how I programmed a lead synth
patch, and how I modified the patch using the modulation matrix to make it even more
burning.

I've called this patch "Big Stereo Lead".  The modified patch is called "Str.Lead Wah".
It was my aim to make this lead patch as "big" and animated as possible. You can gauge
its success by comparing it to the factory lead synth patches - try preset B:82 "Edye
Boost" for starters. I'm sure you'll agree this patch is at least twice as fat!

For lead synth programming, the Super JV is down on a couple of factors to start with:
No oscillator sync, and no Pulse Width Modulation. These are two great resources for
creating fat, animated textures, and the Super JV doesn't have them - strange, as some
of it's direct ancestors *have* had them, eg. the JD-990 (oscillator sync) and the D-110
(PWM). Fortunately, the Super JV has other things up its electronic sleeves to make lead
programming more effective. In these two patches, I've made use of four of them - random
LFOs, Boosters, resonant filtering and EFX programs.

The basis of "Big Stereo Lead" is a sawtooth wave. I've used the familiar technique of
creating the patch using two tones, and then copying those tones. All four tones use the
same sample. For lead synth programming, I always use simple waves - square, triangle,
pulse, sawtooth and sine.

I've used the LFOs to create movement and animation in the raw sound - here, I've used
an LFO with a random waveform. The random waveform is just that: random. You can
modulate pitch, pan level and filter in random, user controllable amounts using this
waveform. I'm modulating pitch by a value of +/-4 for each tone. I've also detuned the
tones by fine amounts using the Pitch parameters. Then, for stereo depth, I've panned
each tone hard-left and hard-right. Detuning and then panning adds a great deal of
stereo depth to a sound, especially for leads and pads - I always aim to have maximum
stereo depth in my sounds before I add any effects.

I've then piped these tones through Structure 3. I've cranked the Booster up to its
maximum +18 dB - this introduces quite a lot of pleasingly rude distortion. As the pitch
between the waves changes in random amounts (through use of the LFOs), so does the
nature of the distortion. At this stage, listen to the patch with the effects diabled -
listen to amount of "buzz" and animation there is in the raw sound.

Before I go any further, I'll insert a clip from last week's post on Structures, as this
patch makes use of the techniques outlined in that tutorial. For more information, I
recommend referring to last week's post.

******************************************************************

WG ----|TVA|----|----|TVF|----|
                |             |----|BSTR|----|
WG -------------|                            |----|TVF| ----|TVA|

******************************************************************

WG   -  Wave Generator
TVA  -  Time Variant Amplifier
TVF  -  Time Variant Filter
BSTR -  Booster

"...The waves of tone 1 and 2 (or 3 and 4) are mixed by the TVA of tone 1, and then are
filtered by the TVF of tone 1 before being put through the wave Booster. The Boosted
signal is then filtered by the TVF of tone 2 and the master output is controlled by the
TVA funtions of tone 2...."

Examine the use of filtering closely and refer to last weeks tutorial to see how I've
arrived at the finished sound. The technique I've used is almost identical.

This patch is polished up by the EFX program ENHANCER->FLANGER. I've cranked the flanger
depth up to its near maximum, and the rate to it's minimum. This gives the tone its
thick, swirling texture. I've also added a mild pre-delay. The enhancer boosts the
high/mid frequency overtone content of the sound, and gives it "bite". Almost half of
the "enhanced" sound is mixed with the original sound.

Well that's one patch, and the next one "Str.Lead Wah" is identically programmed, for
the most part. The difference here is the use of resonant filtering, and the use of the
modulation matrix to put this filtering under the player's control.

Referring to the above diagram, (and last week's post) we can see that tone 1's (or 3)
TVF is located before the Booster. Well, this opens up quite a number of programming
possibilities. For starters, we can introduce a resonant "peak" to the sound, and have
that peak go through the Booster. That's what I've done here: I've used a TVF to create
a resonant peak, and that resonant peak is being processed as well as the raw sample.
Play around with this patch a bit - you'll notice the gnarly, distorted, acidy wah
effect when using the modulation and pitch bend levers.

Under the TVF section for tones 1 and 3, I've selected a Peaking filter. It's like a
Band-pass filter except the level doesn't drop away at either side of the resonant peak.
I've added a resonance amount of 60. The next bit is a little hard to describe. I wanted
a wah-type effect. A wah is in effect a resonant filter with a controller attached to
sweep the resonant peak up and down the frequency spectrum. I wanted a physical
controller onboard my XP-80 to do the same, so I selected the modulation lever. I swept
the cutoff frequency of our peaking filter down to a low amount, around 60. Then, using
the modulation matrix, I routed the Peaking filter cutoff frequency to the modulation
lever. Here's how to do this.

First, access the modulation screen - you'll find it under PATCH/LFO&CTL/CONTROL. You'll
then see a screen like this:

****************************************************************************************

<Common Source>                 <Control Dest: Depth>
1 (Modulation)          ->      CUT:   +23      OFF     0       OFF     0       OFF
2 SYS.CTRL1             ->      PL1:   +20      OFF     0       OFF     0       OFF
3 PITCH BEND            ->      CUT:   +14      OFF     0       OFF     0       OFF

****************************************************************************************

"Common Source" indicates a controller source - most commonly a physical controller like
aftertouch, pitchbend, pedal etc. You can use a maximum of three sources. "Control Dest:
Depth" indicates the destination parameter that controller will be affecting. For each
source, you can modulate four destinations simultaneously. You'll notice "modulation" is
in brackets - that's because "modulation" (meaning, the modulation lever) is a fixed
physical controller: you can't change it. Changing the controller sources and parameter
destinations, however, is as simple as scrolling around the screen to the appropriate
parameter and using the increment/decrement keys.

Here, as I intended, I've used the modulation lever to sweep cutoff frequency, by a
value of +23. This means the filter will *open* by 23 units when I push the lever. A
negative amount would "close" the filter even more. To have the desired effect, the
filter would have to be "closed" (strictly speaking not possible with a Peaking filter,
but stay with me) when the lever isn't being used. That's why on the TVF screen, I
selected a low cutoff frequency to begin with. Now, sweeping the resonant peak using the
modulation lever results in that resonant peak being processed, boosted and distorted by
the Booster - resuling in our raw, synth-wah sound. Still with me? This technique of
using resonant filtering with the Boosters opens up a whole world of synth programming
possibilties.

I also wanted the Pitch Bend lever to open the filter, so I also routed it to cutoff
frequency, though it doesn't open the filter as much as the mod-lever. I've also used
System Controller 1 - in this case aftertouch - to modulate LFO 1's pitch depth. This
gives us vibrato. Examine the relationship between the modualtion matrix and LFO 1, and
see how I've mananged to do this. I'd go so far as to say your patches are only ever
going to be as expressive as your ability to use the modulation matrix. Learning to use
it is very important.

To finish off this sound I've used a Stereo Flanger. Try programming this patch with the
Phaser program as well. You'll end up with a wonderful, morphy texture, that is great
fun to show off with!

Well, that's all for now, I think. Remember, I appreciate your feedback so don't
hesitate to email. And if any of you out there have come up with some new, hot sounds,
why not share 'em? Happy tweaking!!

Best Regards,

Taurus3

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