Unit 5: Synthesizers

The Telharmonium

The Telharmonium, also known as the Dynamophone, was an early 1896 model of the now-famous electrical organ. Created by Thaddeus Cahill, the Telharmonium made use of tonewheels to generate sound from electrical signals via additive synthesis. 

Tonewheels, also used in the renowned Hammond Organ, are electrical devices used to generate musical sounds from electrical signals sent by user input. Mechanically, this device is much more complex, however its mode of operation is not relevant for this topic.

Example of a tonewheel mechanism

While the patent for the Telharmonium was approved in 1987, the first working model was built in 1901. The Telharmonium Mk. 1 weighed 7 tons and encouraged financial backing for the project.

The Telharmonium Mk. 2 would come to life in 1906, weighing in at a staggering 200 tons. 60 feet in length, the organ required 2 players to make use of its 145 electrical generators and multiple keyboards. 

The Cahill Telharmonium Company of New York would make attempts to market entertainment generated by the Telharmonium to customers over the telephone; however, their equipment was claimed to be faulty by the Bell Telephone Company and Cahill was forced to switch to radio technology.

Their efforts would be realised in 1907, though, as Dr. Lee DeForest managed to make successful tests at broadcasting the sounds from the Telharmonic Hall miles away wirelessly.

It would be in 1911 that the final Telharmonium would be built, the Mk. 3. Similarly to the Mk. 2, it would require 2 players and would be installed in a special performance room in New York City.

So, why was the Telharmonium so unsuccessful? Most notably, its size and weight. Other reasons included its hefty retail price ($200,000) and its tendency to interrupt telephone broadcasts, surprising users with unsolicited electronic music. The interest for the Telharmonium dwindled in 1912, and the Cahill Telharmonium Company of New York was declared not successful in 1914.

The Telharmonium

Sources: https://en.wikipedia.org/wiki/Telharmonium

https://en.wikipedia.org/wiki/Tonewheel

The Theremin

Named after its creator Leon Theremin, the no-contact device was invented in October 1920 as a part of a Soviet government research project into proximity research. Leon Theremin would move to the U.S. after its creation, and secure a patent for the Theremin in 1928.

Its strange nature comes from the method of playing it - performers would not touch the instrument, but would simply hover their hands to control the pitch and volume separately. 

The unique sound of the Theremin is created by the 2 aforementioned 'antennae' (they are not actually radio antennae, rather plates of capacitors), which react by producing different pitches and amplitudes depending on their distances from the player's hands. Two oscillators can be found within the pitch circuitry, one at a fixed frequency and the other at a variable frequency to reduce the risk of radio interference.

Block diagram of a Theremin with volume control in blue, pitch control in yellow and audio output in red

Despite the Theremin's ongoing availability, the release of new, easier-to-play electronic instruments following the Second World War would ultimately lead to its decline in popularity. A user of thereminworld.com cites its monophonic nature as one of its primary drawbacks, as so much modern music is comprised of polyphonic instruments (able to play more than one tone at a time) like pianos and guitars.

Although the Theremin has suffered to maintain its impact on the music industry as a whole, it is still commonly used for movie soundtracks and video games for its unique sound.

Etherwave Theremin Kit

Sources: https://en.wikipedia.org/wiki/Theremin#Concert_music

http://www.thereminworld.com/Forums/T/27652/why-has-the-theremin-never-gained-popularity

Synthesis Techniques

Additive synthesis is the process of adding multiple sine waves to create one uniform sound with a certain timbre. 

In life, generally, sounds are not built from only one frequency - a range of frequencies, some more apparent than others, come together to build a certain timbre. Replicating these frequencies with stacked sine waves allowed synthesizers to embody a range of different sounds, like those from a grand piano, upright piano, guitar etc. 

Subtractive synthesis, as its name suggests, is the process of subtracting unwanted frequencies from a sound to achieve a specific timbre. This is done with the use of a filter.

For subtractive synthesis to be possible, a sound must have overtones (any frequency that is an integer multiple of the fundamental frequency, e.g. harmonics). During subtractive synthesis, these overtones are modulated to produce a particular sound.

FM synthesis, or frequency modulation synthesis, is the process of using one sine wave (the modulator) to modulate the original sound (the carrier). This allows the timbre to be altered without the use of filters.

A diagram showing how a complex waveform can be created through FM synthesis. In this case, the modulator is modulating the frequency of the wave.

Physical modelling synthesis is the process of synthesis where the waveform is generated by a mathematical model, equations and algorithms to generate a musical sound. This method of synthesis includes several complex parameters and aims to model the exact physics of a physical sound.

Granular synthesis uses grains (samples 1-100ms in length) layered on top of each other with different speeds, phases, frequencies, volumes etc. This typically creates an atmospheric soundscape unique to the method of granular synthesis.

Sources: https://en.wikipedia.org/wiki/Additive_synthesis

https://en.wikipedia.org/wiki/Subtractive_synthesis

https://cymatics.fm/blogs/production/fm-synthesis?srsltid=AfmBOorsgOmHxCAQeZY2zyy6KCeLt7z0bo0REkRvmMxbzdSCjFILYSiw

https://en.wikipedia.org/wiki/Physical_modelling_synthesis

https://en.wikipedia.org/wiki/Granular_synthesis

Modern Digital Synthesizers

Digital synthesizers rely on DSP (Digital Signal Processing) to produce sound. While analog synthesizers use electronic curcuitry, digital synthesizers are essentially computers with keyboards as they produce all of their sounds digitally. This allows for a combination of techniques, including traditional analog synthesizer emulation and sampling along with digital synthesis.

One such digital synthesizer can be found in Logic by the name of Alchemy. Although there are a wide variety of functions found within, there are certain fundamental features that it is built on.

Alchemy allows for additive synthesis, granular synthesis and spectral synthesis. The sources page contains all of the information for oscillators. To edit the parameters for a particular source, you can use filters, glide, volume, pan, change the number of voices, change from mono/poly, and use your preferred model of synthesis.