The SH-09 synthesizer is a musical instrument capable of generating and modifying electronic signals, thus enabling a wide range of possible sounds. It belongs to the same category of electronic generators of modifiable sounds as the Korg MS-10 synthesizer. Like the MS-10, which was also developed in the late 1970s by a Japanese company, the SH-09 follows the common conception of an analog synthesizer, with its distinction between sound sources (oscillators and noise generators), sources of control voltage (keyboard, low frequency oscillators, envelope generators), and modifiers (filter, amplifier). In the mid-1980s, the paradigm of the analog synthesizer was largely displaced by digital synthesis, notably by synthesizers based on frequency modulation, such as the Yamaha DX7. However, since the 1990s it has seen a revival in interest. Like film photography or vinyl records, in the digital era the analog synthesizer has often been associated with a fuller, more authentic aesthetic experience by a niche group of enthusiasts. Historically, analog synthesizers are also remarkable for their intrinsic similarity with the analog computer, an early computing paradigm that has likewise been largely replaced by its digital counterpart.

The video demonstrates the typical use of the filter in analog sound synthesis. Here, a low-pass filter attenuates higher frequencies while also amplifying a small range around the frequency at which the attenuation starts. Changes in this “cutoff frequency” result in the well-known bubbling or whistling sounds of the analog synthesizer. First, a noise source is used, with different keys and differently adjusted sliders leading to variation of the cutoff frequency and the amount of amplification. The second part of the video shows the use of an oscillator.

Website offering sound examples and a detailed description of the controls of the SH-09 (in German)