Look Ma, No Filters!

So far we've established the Buchla 200e modular system is unique in quite a few ways. One of the most obvious and interesting things I've grown into is it's capabilities without the ever present analog monolithic Lowpass Filter than so dominates most traditional electronic music

Perhaps the most well known filter de
sign is the classic Moog filter. Deep, powerful, ballsy, and used on countless other manufacturer's systems. Then there is the basic Multimode filter which offers Lowpass, Bandpass, and Highpass filtering as well as sometimes adding a Notch filter option. often considered the one filter to have if you're having only one, a multimode filter offers maximum flexibility in sound in a minimum package.

Filter sweeps are more than classic, they are the bread and butter of most electronic music genres from techno to space rock. Where would bands from Prototype 909 to Acid Mother's Temple be without their ubiquitous Frequency Cutoff and Resonance knob twiddling?

Over a decade ago I started experimenting with filterless synthesis. Call it a self imposed limitation if you will but I wanted to see what I could get up to if I took this basic staple of electronic music out. Could I still make interesting modulations? Would the music still have sweeps and creeps and drips and bleeps?

Enter one of the main tools that helped change my mind about filtering, the might Korg ER1 drum machine. While other manufacturers were jumping on the Groovebox bandwagon and even throwing basic filter designs (complete with Freq and Resonance knobs) in their drum machines and samplers Korg went the other direction and built one of the greatest new drum machines adding a Low Frequency Oscillator (LFO) modulation section with multiple waveforms (including noise!) amount and positive/negative directional controls and then allowed you to record live twiddling of all of this LFO madness and save it as part of each pattern.

All of a sudden warping a standard sine wave with a reverse sawtooth and pitch shifting the whole thing down two octaves seemed much more interesting than doing a simple filter sweep on the high hats or snare. You could minimally or drastically alter the sounds via waveforms just like the modulation sections of great old monosynths like the Roland SH101 (which also has a noise LFO waveform) or Sequential Circuits Pro One (a classic design of intermodulatiing VCOs).

Soon I became obsessed with waveform modulation with then lead me to explore all sorts of wavetable synths from the underrated Ensoniq SQ80 to the Waldorf Microwave and of course modular pieces like the Wiard Waveform City, Blacet Wiard Miniwave, original Modcan Wavetable 17A, and others. I even built a DIY 5Pulsar design by Ian Fritz which processed audio into waveforms. Filters? Who needs filters?

Well not to throw the geeky baby out with the bath water but filters still have their place in my music and processing. But my journey without them has helped me rethink their use (and potential overuse). I will happily admit there are few things more Emusically satisfying that tweaking the filter section on my Moog voyager but adding other elements make it really shine.

Enter the Buchla 200e. The system does have a filter module but in my experience I don't miss not having one in my modular at all. First of all the classic Buchla design, the 292 Quad Dynamic Manager, operates as the system's VCA in gate mode but also has it's own unique lowpass filter design as well which can operate in conjunction or separately from the gate function. if you insist on wanted a dedicated filter for the 200e you have the current choice of the 291e triple Morphing Filter or the insanely complex 296e Spectral processor - a 16 channel bandpass filter. If price matters both of these are on the higer end of the already high end price range with the 2926e currently costing the same as a small 200e system all by itself.

Fortunately as with most things Buchla, the complexity of the other modules in the system pick up some features that cover territory outside of their "primary" classic functions. Both the 259e and 261e digital oscillators have a number of features that offer filter like possibilities and truly warp, bleep, bump, and sweep with abandon - all without a classic Freg Cuttoff or Resonance control.

To see how far I could go with this I made a simple patch using both the 259e and 261e and set the 292e in gate only mode. I ran a sequence from the 250e into both and left their pitch CVs constant. I also set the envelope on two sections (one for each oscillator) of the 281e identical and constant. Futhermore I did not tweak the waveforms of either the mod or main oscillators while they were in motion.

What I did do was mess with the various Timbre sections of each oscillator; first manually and then with CV from their respective modulating oscillator sections. Behold an audio demo of Buchlidian "filtering" that uses no dedicated filters:




Buchla 200e Filtered demo with no filters by DAEDSound

The audio of this demo is split in a stereo image with the 259e on the left and the 261e on the right. The clip starts with the 259e and manual modulation of the Warp control. Then the 261e enters with manual modulation of it's various controls. Eventually I bring the 259e back and both Oscillators are modulated by their respective modulation oscillators with me manually adjusting the Mod index amount. Then all hell breaks loose with manual tweaking, crossing the Mod oscillators, patching into the CVs of the Symmetry, High Order, and Timbre controls, etc.

As with all things Buchla, the results are a bit skewed, unique, and left of center. But the aural sound of filtering is there regardless of the math used or names given to the controls. For those looking at getting a small 200e system and concerned about which module to get or leave out I would suggest the 261e does *not* need a dedicated filter to get traditional sweeping results. The proof is in the tweaks.

Bleep on!