Overdrive
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The ESQ/SQ80 doesn’t have an effects section...

-- Or does it?

Some might say that the ESQ/SQ80 series does indeed have two or three hidden effects that seriously transform the sound of your patches. 

This article may be your first introduction to the built-in distortion, saturation and overdrive effect. This hidden feature is another bonus of the powerful architecture that many ESQ and SQ80 owners were never aware of.

ESQ/SQ80 Built-in Distortion Effect

Effects. They are written in synth history. In 1987 Roland introduced the D50.  It had a less than robust synth architecture but it featured rudimentary digital effects (reverb, essentially).

It was a runaway hit.  Synth purists tend to decry such things (even the classic Roland chorus), but I, myself, was well aware that onboard effects were the wave of the future when first I heard the updated Korg Poly 800 II.  It featured an even more basic--but functional--digital delay, which sticklers and other fusspots still criticize.

A guy in the music store was demoing the new Poly 800, causing oohs and ahhs. After each ooh-worth patch, he would comment “the sound is all in the delay”. 

The Roland D50 had an even simpler architecture than the Poly 800, essentially two layered linear paths combined to make a voice (shades of the Yamaha CS80), but, aside from the sample-based oscillator loops, the real “ooh and ahh” of the D50 sound was very much “all in the effects”.

I don’t casually dismiss the D50, but never underestimate the power of the SQ80. Even Roland knew what they were dealing with. For example, D50 owners will be familiar with a preset called “Ensonicq GA9”.   It was a very characteristic Ensoniq analog sound, although drenched in reverb (typical!).  --But now I’m going to show you an effect that the D50 didn’t include on its 16/32 built-in ‘reverb types’.

Overdrive.

Generally speaking, we are talking about distortion, which has become a sort of Holy Grail in music production.   This popular effect is applied mainly to guitars, but can also be used across an entire sound mix--from bass/organ/soloist to just about anything. 

Distortion is introduced by intentionally driving too much signal through an analog amplifier. This process tends to square off the final waveform. In fact, you could say it “clips” the tops and bottoms of your signal. This is where the over-amplification term “clipping” comes from.   You will sometimes see this effect referred to as fuzzSaturation is also similar to the kind of distortion we are talking about, but the term opens up a can of worms beyond the scope of this article.

For our purposes, we will refer to this effect as overdrive, since that is how the effect is really being created.  Overdriven distortion adds additional harmonics and overtones to the signal.  This is often perceived as creating a richer, warmer, more organic sound.

So how do we take advantage of overdrive on the ESQ/SQ80?  Well, since distortion is an amplification effect, let’s lasso them amplifiers! Fire up your synthesizer and head for the Digitally Controlled Amplifier sections (DCAs, numbered 1,2 and 3. DCA 4, the final amp, does not contribute as significantly to this effect).

In a nutshell, the digitally controlled amplifiers can be overdriven--cranked up to “eleven”--to produce some warm acoustic fuzz. 

“Digital” Amplifiers?

“But wait!” you say, “I though distortion was an analog effect!  How can these digital amps (DCAs) create analog overdrive?” Well, perhaps some of you are way ahead of me: The amplifiers in your ESQ/SQ80 are not digital!  The are “digitally controlled”, but they are the same type of chip-based op-amp circuits used in hi-fi receivers and musical instruments for more than thirty years! These circuits pass real electrical signal (e.g. your analog sound, not “ones-and-zeros”) through analog amplification stages, under control of the CPU (the “digital” part).

The only “DSP” in the ESQ/SQ80 is the storage and playback of the OSC waves. After that, the signal is processed in the analog realm, even though it is under control of the CPU.  That is the advantage of digital control: Rock solid logic control, not subject to the variances of older voltage controlled technology.

So compared to the post-1995 crop of “Virtual Analog” synths (I’m looking at you, Nord), the ESQ/SQ80 is analog.  Nothing virtual here.

DCA 1-3 : These go to eleven.

As you might suspect, you go into overdrive when you turn the volume of the DCAs way up. DCA volume levels over the +50 mark tend to induce saturation, with distortion increasing as you peg out at the +63 maximum.  You’ll notice right away, that the technique that causes this overdrive is “real”, not a software or circuit-based simulation. Nothing is being faked, as the amplifier is literally being overdriven by too much signal, just as nature intended. Now, on the “fake” side, the SQ8L VST instrument makes a good attempt at simulating this effect in software (see the sidebar below).

Fakin’ It

Simulating saturation with the SQ8L VST

The SQ8L models the sound of it’s hardware predecessors to a remarkable degree. One of the factors contributing to this is the many useful ways the SQ8L give you to simulate the built-in DCA overdrive. There are DCA “smoothing” options both for the oscillator DCAs as well as the final volume DCA. 

If you’re running the widely distributed v0.91 version, take a look at the Options/Emulation menu.  I would leave it to “Set to program”, which allows individual patches to control their own overdrive.

Now load up a patch that would benefit from distortion.  Anything with PWM in the name is a good candidate. Select the teal blue-colored  MODES/EMU button and “arrow down” to the bottom of the display, the “EMU SMOOTH” page.

Set the DCAs to “EMU” and adjust the DCA 1-3 levels.  If it helps, add a “brick wall” volume normalizer (but do not compress the levels!) to the bus.
Additionally, load up a spectrum analyzer plug like Computer Music’s FreqAnalyst.  Play with the levels and you’ll be able to see--and hear--the fuzz fogging up the sound like a photograph filtered through a scrim of cotton.

In spite of what you may have read on the Internet, the overdrive effect is not just “automatically” switched on any time you set a DCA volume at a value over +50.  There are two factors which work together to deliver built-in overdrive:

  1. Overdrive is cumulative based on DCA volumes.
  2. The amount of overdrive depends on harmonic saturation.

The effect is additive, based on the values of other DCA’s.  A lone oscillator at a value of +63 overdrives a little.  Two oscillators at volumes of +60 overdrive even more (even though they are individually set to quieter values). Finally, three oscillators set to volumes of +57 will overdrive much more pleasantly than two loud oscillators. It’s essentially a summation effect

We have seen how the stacking of oscillators with volume levels higher than 100% is the catalyst for the distortion effect.  But the degree of distortion is determined by harmonic content, which we will discuss next.

The amount of the effect varies depending on the harmonic complexity of the oscillator being amplified.  What does this mean?  It means that simple waveforms like sine waves, metallic 1-shot partials and formants can’t be expected to overdrive with any regularity. 

On the other hand, harmonically rich waveforms like the ORGAN, SAW, NOISE and the other complex sampled waveforms, such as PIANO, are a veritable distortion-palooza!  Take a look at the rules of thumb below:

Distortion is based on sonic complexity:

  • 3 sine oscillators (harmonically simple) will not audibly distort at maximum values, but you can detect measurable distortion with an analysis tool.
  • 1 saw oscillator (harmonically rich) will noticeably begin to clip at +60 through +63.

Distortion is also based on cumulative amplifier volumes:

  • 2 saw oscs begin to distort when both are over +57 through +58
  • 3 saw oscs begin to distort at values over 50 (depending on other DCA and filter setings)

You could say that the 100% volume setting for a DCA is +50.  This is an axiom, however, not an absolute rule.  Using the rules of thumb above as your guide, you’ll soon develop a sense of how hot you can dial each individual patch before it starts to distort.

Upshot:

So how much distortion are we talking about? Certainly not Jimmy Hendrix levels here. If you had visions of creating a destroyer guitar wrapped in a massive wall of fuzz, I’m sorry to disappoint you.

Even though some of the folks on the web who have done harmonic analysis report a visible harmonic boost even on a single OSC sine wave, to the naked ear, the thickening effect will be understated. This patch-level overdrive is a subtle but distinctive effect. Your mom may not notice it, but it can provide a distinct extra layer of veracity and professionalism in a patch--the sheen that separates your work from the merely pedestrian.

If you like the idea of thickening up your synth leads or adding an extra layer of realism to your Hammond organ patches, you should definitely utilize the higher values to thicken up your sound. Distortion and Pulse Width Modulation go hand in hand for example.  And some of what you’re responding to in the terrific POWERSYNCH preset is the overdriven amp section caused by that big sound.

Now that you know about it, go forth and use this feature to your advantage!

But don’t use it everywhere! Think critically of its use on patches that don’t benefit from fuzz, like crystal clear bells or woodwind sections. You might consider reducing your DCA volumes below the +50-level to avoid the introduction of unwanted distortion.

Indeed, super-synth boffin Kirk Slinkard (who is all over the other pages of this website, by the way), recommends compliance with the programming standards laid out in Transoniq Hacker magazine issues 33 and 49, and we will not debate his profound wisdom at these proceedings:

Basic Standards: http://www.buchty.net/~buchty/ensoniq/transoniq_hacker/PDF/033.pdf#page=16

Tuning Addendum: http://www.buchty.net/~buchty/ensoniq/transoniq_hacker/PDF/049.pdf#page=20

Distortion Do’s and Don’ts

Do set DCA 1,2 or 3 over +50 to induce subtle overdrive.

Don’t use the overdrive effect on every patch.  Use it on the right patch.

Don’t expect noticeable distortion on harmonically simple sounds. A good rule of thumb is that if your sound is comparatively quiet with all the DCAs set to average values, then it is probably too harmonically tame to induce additive overdrive.  But tame sounds are just as important as chaotic ones.

Don’t expect massive Jimmi Hendrix overdrive.

Do use it on your AM Synch and PWM sounds. These are distortion-loving techniques .

Do feel free to run the synth through a guitar pedal, Amplitube, or similar, in order to just go nuts with distortion.  Consider it a cathartic exercise, balancing both the subtle and insane flavors of overdrive. Very Zen.  You’ll literally have distortion coming out the yin-yang.

Lowering the volume of certain patches to reduce distortion may leave some of your patches quieter than others.  But you may have noticed that there is no standard for patch volumes anyway. --Because of this, certain performers play with a compressor/limiter wired right out of the line level inputs. 

I would encourage you to perform this kind of volume balancing “after the fact”, when you have more time to tweak the volume levels in your mix. if you’re like me, you normalize your DAW tracks anyway, so volume levels can easily be balanced once you bounce your MIDI synth tracks to audio.

Conclusion

The built-in overdrive feature really is a feature, not a renamed bug. The designers were aware that they could run the maximum volume levels slightly “hot”, and thereby achieve a desirable musical effect.

It’s possible that you may have been subconsciously using this effect for some time. I know I gradually become aware of the effect DCA levels had on my sound after I started recording digitally, and could easily monitor subtle changes in volume and their effect on the tambours.  There was a noticeable difference in raising the volumes in Pro Tools versus raising the volumes with DCA levels.

Now that you are more aware of it, consider it a subtle “power-up” to your productivity as a sound designer.  You now have a little extra trick in your bag of holding that a mere mortal sound designer just doesn’t have!

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