Virtual analog synthesizer

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A virtual analog synthesizer is an electronic musical instrument and a special type of synthesizer . It digitally emulates the behavior of the circuits of a classic analog synthesizer by calculating its behavior. This is done on a computer (as a software synthesizer ), on a sound card with a sound chip or on special hardware on which there are digital signal processors or FPGAs and suitable firmware . In contrast to the circuit simulation , all calculations are carried out in real time .

history

Clavia Nordlead

Virtual-analog synthesizers emerged at the end of the 1980s after the introduction of physical modeling - a form of synthesis that tries to imitate the generation of physical vibrations using mathematical models. They experienced a boom in the 1990s, initially as pure hardware solutions, then (from around 1997) increasingly also on a pure software basis. Some well-known synthesizers of this type, such as the Yamaha AN1-X , the Clavia Nord Lead and the Access Virus , became iconic devices. Companies such as Waldorf and Novation were also able to establish themselves in the VA synthesizer sector.

function

The electronic circuit is analyzed and the component behavior is converted into mathematical models. Depending on the type and scope of the platform and the computing power available on it, the models used vary in complexity and thus different degrees of proximity to reality. The spectrum ranges from the simple emulation of the oscillators used in synthesizers by means of sine waves through the use of oscillating circuit models to the complete calculation of electronic components. Similar to a circuit simulation in SPICE , the inadequacies and non-linearities of real electronics, which are the reason for the deviations from the simple ideal mathematical behavior, can be simulated very differently.

criticism

Critics - mostly fans of real analog synthesizers - complain that this method results in losses in the sound: Since the resolution (measured in kilohertz for the frequency representation and in bits for the amplitude ) determines the precision of the calculation process, the sound is only very high Resolutions realistic. In addition, the property of analog synthesizers to produce unpredictable errors that are partly responsible for their sound character cannot be reproduced and therefore the sound of virtual-analog synthesizers is more “sterile” than that of the originals.

The counter-argument put forward is that with the resolutions commonly used today (96 or 192 kHz / 20 or 24 bit), differences to the analog sound image due to the resolution are as good as inaudible. The only decisive factor is the quality of the model used and the calculation accuracy used. In modern virtual-analog synthesizers, the emulation of the "errors" of analog devices is also increasingly taken into account and implemented in the wave algorithms . This is countered by the fact that compromises are often made in terms of resolution and model accuracy due to the limited computing capacity. By simplifying the algorithms, more voices can be calculated on synthesizers and this is a stronger selling point.

An existing problem is that all digital synthesizers are controlled via the MIDI protocol and this only provides 7-bit for most parameters, which is why VA synthesizers in particular almost always use all internal parameters only in this resolution. This results in low modulated values ​​for z. B. the volume, vibrato or cutoff frequencies of filters comparatively coarse gradations. Should z. If, for example, a frequency-determining value for a filter that is 50 should be reduced by 10%, only 5 levels would be available, which would lead to jumps. Therefore, all incoming MIDI commands from the internal control group or external devices must be artificially smoothed to avoid audible levels. This leads to inaccurate behavior, while with the classic analog devices the parameters are specified via stepless potentiometers and have a delayed effect. This applies in a similar way to the MIDI-capable (retrofitted) analog synthesizers, which only process the note information and also have potentiometers for controlling the assemblies. This problem was not addressed until 2020 with MIDI 2.0 .

credentials

  1. ↑ Green Box: Yamaha AN1X VA synthesizer. In: AMAZONA.de. March 6, 2010, accessed July 26, 2020 .
  2. ↑ Green Box: Clavia Nord Lead, VA synthesizer. In: AMAZONA.de. April 7, 2012, accessed July 26, 2020 .

Web links

literature

  • Michael Dickreiter, Volker Dittel, Wolfgang Hoeg, Martin Wöhr (eds.), "Handbuch der Tonstudiotechnik", 8th, revised and expanded edition, 2 volumes, publisher: Walter de Gruyter, Berlin / Boston, 2014, ISBN 978-3- 11-028978-7 or e- ISBN 978-3-11-031650-6