Lisääväsynteesin

Lisääväsynteesin, a Finnish term, translates to "additive synthesis" in English and refers to a fundamental sound synthesis technique in electronic music and audio signal processing. This method involves constructing a complex sound by combining multiple simpler waveforms, typically sine waves. Each sine wave, often referred to as a harmonic or partial, has its own specific amplitude (loudness) and frequency (pitch). By carefully controlling the amplitudes and frequencies of these individual components, additive synthesis allows for the creation of a vast array of timbres and sonic textures.

The process begins with the selection of a fundamental frequency, which determines the perceived pitch of the resulting sound. Then, a series of harmonic frequencies are added to this fundamental. These harmonics are usually integer multiples of the fundamental frequency, forming a harmonic series. However, non-harmonic partials can also be included to create more complex and sometimes dissonant sounds. The amplitude envelope of each individual partial is also crucial. This envelope dictates how the amplitude of each sine wave changes over time, allowing for the shaping of the sound's attack, decay, sustain, and release. For instance, a rapid attack and short decay on the fundamental and lower harmonics, combined with a slower decay on higher harmonics, can create a percussive sound with a bright, evolving overtone structure.

The computational requirements for additive synthesis can be significant, especially when generating sounds with many harmonics. However, its strength lies in its direct control over the spectral content of a sound. This makes it a powerful tool for sound designers and musicians seeking to meticulously craft specific timbres, recreate acoustic instrument sounds, or explore entirely new sonic territories. Early electronic instruments like the Telharmonium and more modern synthesizers utilize additive synthesis principles, demonstrating its enduring relevance in sound creation.