The voltage was then transformed into sound with an amplifier. The notches of the disk created periodical tension variations which were then translated by the coil into electrical voltage. This huge instrument, which weighed 7 tons (and which transmitted sound via phone lines!), worked according to the principle of tone wheels, where a notched disk turned in front of a coil (like on electric guitars). by Thaddeus Cahill, who would manufacture a second version in 1906. The Telharmonium, the first instrument of the modern ─'electric' ─ age, appeared in 1896.

In fact, you could argue that one of the first instruments of additive synthesis was.the pipe organ! And there are several reasons for that. But the principle behind additive synthesis had been applied to music way before Fourier formulated a theoretical basis for it. It's important to note, however, that the solution to every analysis has some limitations and, thus, it's impossible to reproduce identically a sound previously analyzed.

And he quickly came to the idea of doing the exact opposite to recreate the complex sounds previously analyzed, stacking up their basic sine waves. Remember, it was he who discovered that all complex signals can be reduced to a group of sine waves. This procedure rests upon the work of one Joseph Fourier, whom we have briefly mentioned in this series before. Unlike subtractive synthesis, which consists of taking away elements of an harmonically rich audio signal, as if you were sculpting a marble statue, additive synthesis is based on the principle of stacking up simple audio signals to create a richer sound. Today, we'll meet the most ancient, but still very actively used, form of synthetic sound creation: Additive synthesis.

Additive vs subtractive synth