2010
Didge(R)Evolution Instruments 
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Since the launch of the Didge(R)Evolution tools over two years ago, in several projects with instrument makers, musicians, sound therapists, and didgeridoo enthusiasts a number of interesting instruments were created. Because a certain number of alternative interior forms exist for any pre-determined set of sound characteristics, now the directed-evolution search algorithms are developed to select the forms with the best possible playability.
Größtes (232 cm) und kleinstes (123 cm) Instrument |
Example of an acoustic reconstruction of an instrument based of an old Adam Plack record (1992). Built and artistically designed by Bernd Lötzsch.
When exists good acoustic recordings, the appropriate internal forms are always found, because these instruments already exist or have existed, and so it is physically possible to reconstruct the sound characteristicsis by using the Didge(R)Evolution tools. The more sound information in a record are included, the more effective the associated internal forms can be found.
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Example of a desired sound-design of a modern instrument for Dan Flynn. For Dan's playing style, an interior form was found for an instrument with 6 pre-determined, playable natural resonances (Drone and Toots C,C,G,C,F,G#). Dan has built one of the forms found for this instrument (evo-4, Anyuta didge) and recorded the following sound example. Due to Dan's special playing technique and the use of flanger and delay effects, the piece reminds some of a Cello (particularly at about 4 min.). In addition to the projected playable Toots (Overblows, Intrinsic Resonances), Dan is also able to play (by good lip tension control) additional Toots known as "Pseudo Toots". In this example, the following sounds are played: |
G' |
Pseudo Toot (below Fundamental) 1st Intrinsic Resonance (Fundamental) Pseudo Toot (less easily playable) Pseudo Toot (less easily playable) 2nd Intrinsic Resonance (First Toot/Overblow) Pseudo Toot (less easily playable) 3rd Intrinsic Resonance (Second Toot/Overblow) 4th Intrinsic Resonance (Third Toot/Overblow) 5th Intrinsic Resonance (Fourth Toot/Overblow) 6th Intrinsic Resonance (Fifth Toot/Overblow) 7th Intrinsic Resonance (Sixth Toot/Overblow) (not specifically designed for) |
As part of this project, other instruments were designed to allow for additional playable pseudo toots between the standard series of overblow/toot resonances. These pseudo toots are playable as fundamental frequencies (by players with good control of lip vibration frequency) because a number of their harmonics fall on higher natural resonances. When such pseudo toots fall below the fundamental tone in frequency, they are playable as "undertones". Instruments with such properties below the natural fundamental frequency are sometimes called multi drone instruments too. By using the Didge(R)Evolution tools the location of this additional drones / "undertones" can pre-determined and are no longer random products.
Simulated Spectra Using CADSD Software (0 – 1000 Hz):
Black Peaks: Impedance spectrum, playable intrinsic resonances (Toots)
Gray Peaks: Summation and weighted impedance for the respective frequency's associated harmonic overtones
Red Peaks: Fundamental tone sound spectrum
Blue Peaks: First overblow sound spectrum
(The sound spectra for the other overblows are not shown for clarity.)
Examples for the design of instruments for special traditional styles and playing techniques. Greetings from the "virtual termites".
Yidaki-type instrument for NEAL-style (North-East Arnhem Land) built and artistically designed by Manfred Scheffknecht
By the symmetrical balancing of the intermediate and higher overtones to the location of the natural intrinsic resonances this instrument is playable pleasantly elastic and reacts with ringing overtones. The first overblow (toot) a half tone above the octave is playable light and soft.
Mago-type instrument for WAL-style (West Arnhem Land) built by Manfred Scheffknecht
By the Mago-typical location of the second and third natural intrinsic resonance -> combination tones from the fundamental drone and voice are especially emphasized. This heterodyne effects leads to an interesting contrast to the higher overtones.
Mago-type instrument for WAL-style (West Arnhem Land) built and artistically designed by Frank Geipel
Simulated Spectra Using CADSD Software (0 – 1000 Hz):
Black Peaks: Impedance spectrum, playable intrinsic resonances (Toots)
Gray Peaks: Summation and weighted impedance for the respective frequency's associated harmonic overtones
Red Peaks: Fundamental tone sound spectrum
Blue Peaks: First overblow sound spectrum
Associated FFT analysis of the actual built instrument in waterfall display:
The signals (in the lower third) are produced by slapping a hand on the instrument mouthpiece and holding it closed, and they correspond (in location) to the simulated black impedance spectrum. The signals (in the middle third) correspond to the red spectrum of sound when playing the simple fundamental. The signals (in the upper third) are produced by "passive" voice-assist technology to generate the typical mixed-Mago frequencies (heterodyne effects).
If the voice frequency (f voice) is sounded at a fifth above the fundamental frequency (f fundamental), the resulting combination tone or combination frequency (f voice + f fundamental) with this Mago type instrument is reinforced by the position of the second resonance frequency. Also, the resulting difference tone or difference frequency (f voice - f fundamental) below the fundamental is reinforced, giving this small instrument a fuller bass. In addition to these simple combination and difference frequencies, other combination tones arise from the overtones of didge tone and voice tone.
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