Ahornberg’s Malleability and How Computer Programs Mold Music

How do we evolve the 30 seconds of audio from the track above to finished seven-minute product, featured at the end of the article?

Music’s cutting edge is quite the departure from the stylings of Andres Segovia strumming on an acoustic guitar. Computers allow programmers to create the ultimate musical experiments by breaking down music composition at its base, mathematical foundations. The results are indisputably fascinating and drivingly visceral, but often risks pushing the limits of even the most ardent fans of ethereal audio.

An excellent case in point lies within the works of Vienna’s experimental and microtonal Ahornberg, whose latest album, ambient workout IV, was released on March 28th, 2016. Ahornberg describes the album as an evolution of the first track, The Source – a jarring bit of coughing psychedelia- to the final track, Melting Windshield Frost. The culminating track’s muse was a haiku by Michael Neal Morris

Melting windshield frost

Warm guitar in thin earbuds

Sun coming through leaves.

To get from point A to point B, Ahornberg enlisted the help of two programs: Paulstretch and Kaleidoscope.

Paulstretch is an open source program which literally stretches the audio, spectrally smooths the sounds and turns them textural. It doesn’t hold back, stretching audio 50 times beyond their original capacity. Your three-minute song now three hours of noise.

Created by Paul Nasca

This program doesn’t process the sound as a single piece: it cuts the sound in small pieces and process them. Each small piece is called a “window”. The size of the windows controls the size of the window in samples, which affects the frequency and the time resolution of the resulting sounds. The small windows have good time resolution, but poor frequency resolution. Also, large windows has poor time resolution, but they has great frequency resolution. Usually, a window of 7-12k is good for most music. Very big windows (larger than 100k) can be used for special effects (for smearing the sound very much and transforming it into a sound-texture even if the stretch is closer to 1.0).

If the playback is on and you change the window size, you have to press play again to have effect on the current playback.

Also, the window has another control, which is the type of the window. It set a trade-off between frequency resolution and the noise. The Rectangular/Hamming types has the best frequency resolution, but they produces a lot of noises. The Blackman types produces almost no noise, but has a slightly lower frequency resolution.


Kaleidoscope, meanwhile, is an amazingly spectral tool, which nearly allows you to create audio from pictures.

Image courtesy of 2CAudio

Kaleidoscope is both an effects processor as well as a content generator, meaning that it is possible to synthesize completely new sounds without any input sound or MIDI performance data as well as to transform incoming audio signals in other-worldly manners.

Kaleidoscope uses pictures to control sound. It scans an image from left to right where the horizontal access represents time, and the vertical access represents frequency. The brightness of a particular pixel in the image determines how loud the sound will be at that particular point in time and frequency. This is similar in some ways to a spectrogram or even to piano-roll notation in standard musical sequencers. The difference is in scope and the unprecedented level of control and flexibility offered by Kaleidoscope.

A single Kaleidoscope instance uses up to two pictures that can provide over two million points of stereo automation data to create incredibly intricate performances that evolve in time, frequency and space. These performances can be set to have any desired duration: an image could represent a one measure loop, providing 1/1024th note timing resolution, or it could represent an entire ten minute song. A single pixel could represent anything from one audio sample to one minute, one hour, one day, or more in duration, giving unprecedented control over performance time structures. Timing is sample-accurate for all cases and any tempo. Finally the timing of each Image Map performance can be independently set to establish evolving patterns and polyrhythmic structures that generate incredibly novel and interesting results that are guaranteed to keep the listener engaged with new surprises.


Obviously, these excerpts are tips of the icebergs in regards to such intricate programs. No one can be blamed for their eyes starting to glaze once getting into the grit. But Ahornberg has been able to properly utilize these programs towards creating an evocative final product. Because of the way that ambient workout IV is set up, we can get a pretty good idea of how he got from beginning to the end.

Originally The Source is a mere thirty second long. Ahornberg then stretches it 222 times, which serves as track two. He follows with using Kaleidoscope, then more time stretches and track manipulation. Lastly guitars are introduced and a third time stretch batch of 55. The final product is a mellow, layered piece of ambient music that is easy to get lost in.

Much of the composition along the way is a very difficult listen. It’s too much white noise and runs long. But it’s a great journey and a wonderful example of creatively using programs as instruments.  Appreciate the process an artist endures to get to the end of the road and it’s likely to learn something new as well.

Check out this musical workout, and more of Ahornberg’s music, here.

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