Topic: My discovery: High frequency, low pass filter modulation

In honor of Robert Moog, I’d like to to share a discovery I recently had, a discovery interesting for you who are familiar to the world of modular synthesis. Chances are, there aren’t many of you around like me here, but I thought I’d give it a go anyway. If you share my interrest for synthezisers, I encourage you to read on.

It all started with the discovery of a British band named Redshift formed by Mark Shreeve. For those of you who are interested in electronic music and analog synthesizers, Redshift is a real gem. They sound a bit like Tangerine Dream did in the virgin years, only better in my opinion, and with a distinctive sound.
My first encounter with was their album “Halo”. When I first heard it, I instantly recognized that classic Moog Modular sound I’ve become familiar with on several Tangerine Dream albums, and read about in interviews on http://www.redshreeve.org

Perhaps you might think that key words like, “classic”, “analog”, and “Moog” (long live the memory of him) add up to a smooth, warm sound? Think again.

To make this easier to explain, download and listen to this excerpt of the first track, named Leviathan from the “Halo” album:
http://hyper.ia.agh.edu.pl/~rork/mp3/halo/Redshift%20-%20(Halo)%20-%2001.Leviathan.mp3

Copy the entire URL to get the file.
(The [url] bbCode tag doesn’t work with parenthesis signs 😯 )

The Moog can also sound very harsh and rough, and this is basicly what this post is about.
What makes Redshift sound so distinct, is not only their combination of instruments, but a clue lies in the way Mark uses the filters in his Moog Modular.
In the beginning of Leviathan, you’ll hear what you’d normally expect from a Moog Modular system, which is of course that heavy, warm and punchy sound the Moog name can be associated with. But, as the track progresses, something happens, something weird. It sounds like nothing else I’ve ever heard before, coming from an analog synth. At first, it sounds like some sort of harsh, metallic, digital lo-fi trickery, then you might think this is high pitched ring modulation. But, as you hear other tracks under the Redshift name, you will conclude this sort of sound simply cannot be done with a digital effect processor or a ring modulator in the signal chain.

As time went on, I listened to everything I could grab a hold of by Redshift. I though of many ways of how to do this particular sound. I tried and failed with ring modulation, high frequency oscillator modulation and so on….
One day, a good friend of mine told me to try and modulate the cutoff frequency of the filter in a rapid manner, and I don’t mean rapidly as in 10 to 540 Hz for instance, he suggested 1000 to 3000 Hz. I though it sounded so crazy that it actually would work. And it did!

So, how would you go about to try the same thing?
Well. first you’ll need a well written software modular synth, such as VAZ Modular or Reaktor. The clue with these software modulars is that they update their parameters on a per-sample basis. If you’re lucky, you might actually own a hardware modular. This trick applies to both worlds anyway.

To start, build your standard subtractive patch with two, maybe three oscillators, two envelope generators, a mixer, an amplifier and one 24db/oct low pass filter, as if you were to mimic the sound you hear in “Leviathan”.
Now comes the magic. When you’re done patching this seemingly basic structure together, add an additional sine wave oscillator patched through an attenuator before feeding it to one of the modulation inputs of the filter. Tune the sine oscillator to around 2khz to start off, and slowly open up the attenuator to modulate the filter cutoff as the sound plays. There you are!

Although not directly Podium-related, I hope some of you may find this interesting. If you have questions, don’t hesitate to ask, I’ll be happy to help 🙂

/Joachim