December in a loop

Tue, 29 Dec 2009 12:53:25 +0000

As we head for the end of 2009 I thought it might be a good idea to put down some thoughts about what I am doing in my favourite hobby. This marks the end of the first full year of musical exploration and, with my experiments with building a Reaktor based looping instrument, I finally feel like I am beginning to earn my khaki shorts and pith helmet.

I got inspired by reading about Steve Reich and his 60's experiments with phase shifted looping. Notably It's Gonna Rain and Piano Phase. The basic principle is a simple one: Play two identical loops of sound at different speeds and they will drift out of phase from each other and these phase differences will create interesting effects and counter rhythms.

Here's a fantastic clip from a South Bank show on Steve Reich that discusses this early period of his work (Parts 1, 3, 4, & 5 are also available and recommended viewing if this kind of thing is at all of interest to you):

Throughtout December I have been experimenting with phase-shifted looping through building a Reaktor ensemble that I call The Reichatron. At heart Reichatron consists of three granular sampler modules. Why 3? I'm not sure but everyone else was using two so I decided to use 3.

The granular in granular sampler is important because, instead of treating a sample as a single chunk of audio they represent it as a stream of audio grains which may be only a few milliseconds long. The sampler module then resynthesizes the original sound by blending some of these grains. The advantage to this method is that the sampler can vary the speed of sample playback without changing pitch and vice verca. This turns out to be a very handy property.

In Reichatron the playback speed of each sampler can be varied independently. I normally set one to normal speed (1.00x), another to 1.01x, and the third to 1.02x. But I've also experimented with other relationships including reverse speeds with the same kinds of relationships.

A very early example of what I produced is Gnossiennes-1 Reiched Pt. 2 which takes a recording of the Erik Satie piano solo piece Gnossiennes #1 and loops sections of it.

The result is, I think, quite beautiful in itself and, I hope, does no injustice to Satie's work (a favourite of mine and piece I hope, eventually, to learn to play).

A few weeks later and Reichatron had evolved into a somewhat more sophisticated beast as I discovered that layering effects such as delay and reverb over the basic phase-shifted looping lends a more polished quality to the result. For example a piece I made from a 2 second long piano sample called Reichenbach Piano 1

Now one of my favourite Reaktor ensembles is called Metaphysical Function. Created by Mike Daliot, it is a monster of a sound generator that combines several oscillators, a sampler, and an effects signal chain.

One of the things I loved about MF was the way that automation of the controls was built right-in and I resolved to learn how to do that myself. Copying the structures from Metaphysical Function itself was impossible as the ensemble is insanely complex. I decided to take the challenge of learning to build them from scratch.

This turned out to be several weeks work and I was grateful for the assistance of my Reaktor tutor Ernest Meyer, a real old-hand, who helped me steer some of Reaktors dark waters. I was very pleased an happy that I was able to upload a finished & working control to the Reaktor User Library (my first such contribution).

Later on it occurred to me to also try modelling some of Metaphysical Function's signal chain for Reichatron and this began the process of Reichatron evolving from a fun experiment into a real instrument.

Again it was pointless to look at Metaphysical Function as anything other than inspiration so I copied the high-level block structure of oscillators (in my case samplers), filter, distortion, EQ, resonance, and reverb and substituted in components of my own, components from the Reaktor Factory Library, and some useful stuff from the User Library as well as a contribution from Computer Music's own rachMiel when I was having trouble building a resonator.

At the same time as I was developing the signal chain I was also experimenting with different ways of navigating the loop points of the sample being played devising different modes. In the beginning I started with one knob to control the start position of the loop and one to control the length. By the time I release Reichenbach Rekkerd 3

I had evolved the controls to include a range of modes. This piece uses drift mode which randomly introduces small variations into the loop start & end points. Rekkerd refers to Ronnie from rekkerd.og who provides a range of great, free, samples on his site.

One of the best comments on this piece was from Sister Savage who wrote that it was like:

"Some kind of underground bug conference, with drinks."

I liked that a lot. Indeed I have been very gratified that a small audience has developed who seem to enjoy these rather strange experiments of mine.

I kept improving both the signal chain and the looping modes and one of the more interesting pieces to come out of this process was Twisted Reichazoid 1 which has a rather experimental sound. But I liked it a lot.

A few days ago I reached a point where I feel Reichatron is beginning to look like a "finished version 1". To show off where I had got to I made the piece Reichatronic Flute 2.

along with an accompanying screencast:

The screencast shows the various features of the ensemble and I think the similarities between Reichatron and Metaphysical Function will be quite apparent. I hope Mike Dalliot wouldn't be too offeneded that I try and put myself in the same space.

There's a little more work to do on the looping modes, then I will select some samples for release and create some presets to demo it. Reichatron will be my first instrument upload to the Reaktor User Library and I am hoping other people may enjoy playing with it and, if they do, what they might come up with themselves.

What I have in mind for the future of the instrument is greater control over how the loopers and the signal chain interact to create more interesting compositions. But first version 1!

All in all December has been a most interesting month!

Curiouser and Curiouser! on steve-reich

December in a loop