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The Slinkard Maneuver*

*(Not a paperback bestseller about high-tech espionage in a big city!)

This article will explain how to generate real variable width Pulse Waves on the ESQ/SQ80 or SQ8L VST.  Yes! It can be done!  And the method used to add this feature has come to be known “The Slinkard Maneuver” since the early 90’s.

But first, let me explain the standard operating procedure around here:

I Know My Limitations

I am not an electrical engineer or hardware genius. If you have a mechanical problem with your synth, I cannot fix it. Rainer Buchty and a few guys on the SQ80 mailing list have that propeller-headed Thomas Edison territory all locked up.  

If there is one tiny area of expertise I think I “own”, it is know-how in sound design and synthesis:

Given enough cables, I can patch a modular together to actually produce sound (!).

I used to be an expert in something called SuperCollider for granular synthesis, and I can actually rub four or six FM operators together to produce a harp or a bell piano before it starts to sound like Harvey Fierstein yelling into a garbage disposal (a not-uncommon occurrence, they tell me).

I once wrote enough lines of VB sound statements to replicate a digital sample of a creaky door slamming via the PC “beeper” speaker (because the customer didn’t have Soundblaster cards installed in their 486 PCs). Everyone thought they were hearing the real sample, but it was all square waves chopped up real tiny.

I Know My Strengths

So I should be able to claim a wee bit of synthesis expertise as my own little corner of the ESQ/SQ80 Universe, right?

Unfortunately here’s how things usually work around here:


What Is PWM?
And Why Should I Use It

Pulse Waves are a special kind of Square Wave that can be changed (modulated) from perfect, box-shaped square waves to narrow, sawtooth-sounding “rectangle waves”.  They’re a powerful addition to your sound palette in two ways:

1. Its like adding dozens of new waveforms to your old oscillators

Imagine if you could fine-tune each kind of oscillator to add different harmonics: Bring up only “even” harmonics, or dial-in only the “odd” ones -- or find a mixture of both!  Pulse Wave Modulation gives you a new level of harmonic control.

2. PWM isn’t just Static:  You can vary the width of the waveform While You Play

Pick any normal OSC Wave and you’re stuck. It’ll play the same way each time.  Even if you modulate it somewhere later in the voice architecture, you’re only changing the wave after the fact.  But not so with PWM!  Since they are “Variable Waves”, Pulse Waves can morph as they play, independently of any other modulation! It’s like having a head-start on creating complex timbres!

The ESQ/SQ80 Advantage!

Most Pulse Wave-capable synths offer PWM on square waves only (by definition).  But with the ESQ/SQ80, this technique applies not only to square waves but any other wave you can dial up.  You can create thousands of sounds that would be impossible on any other synthesizer!



    Hey, I’ve discovered a new trick.  I think I’ll make a page on the website to show it off.



Kirk Slinkard:

    Yeah, I wrote an article about that in 1991 for the Hacker.  I’ll send you a copy.


I Know When I’m Out of My League

Then the buzzard has the unmitigated gall to send me the article, providing documentary evidence that he is about 20 years smarter than me.

It’s a humbling experience, folks.


What I Bring to the Picnic

And true to form, Kirk Slinkard cracked the PWM on ESQ/SQ80 tutorial two decades ago.

So what can I do, beside reprinting Kirk’s article in its entirety? Well, since he attacks the problem from more of a technical angle, I can add some intro material about what PWM is, and why you would want to do it.

I can also throw in some audio examples, make his patches downloadable and add a couple sidebars to hand-hold novices through the technique. I’ve also illustrated the article with pictures of girls in miniskirts, which is never a bad idea.

See? I told you I was a genius.

Meanwhile, remind me to ask Kirk if he has any good stock picks or Superbowl wagers.  I bet I could make a fortune. 20 years from now. 


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