BREAKING DOWN THE ANALOG SYNTHESIZER An analog synthesizer is a music instrument that produces Analog synthesizers first appeared in the sounds using analog electronic circuits. In order to properly 1920s and 1930s, but became popular in understand what it is and how it works, it is important to the 1960s and 1970s. They declined in understand the differences between analog and digital popularity in the 1980s due to the synthesizers. Although the two can produce similar sounds, emergence of digital synthesizers. their differences begin fundamentally in their design However, recent years have seen a philosophies. resurgence in the popularity of the analog synthesizer. Digital Synthesis Digital synthesizers produce sound using techniques of digital signal processing, in which waveforms are represented as sets of discrete quantities and manipulated in terms of those quantities. In this way, a signal is closely approximated to its actual behavior, while existing in a form that allows the instrument to easily perform operations on it. The same technique is used in creating an MP3 file of a song. The digital synthesizer was invented to reduce the amount of hardware in a synthesizer by putting signals in a form A signal and its digital representation recognizable and producible by Source: http://www.diracdelta.co.uk computers and microprocessors. Digital synthesis has several inherent drawbacks that cause many to prefer analog synthesizers. First, representing waveforms as a set of discrete numbers limits the range of possible sounds a digital synthesizer can create. Secondly, digital synthesis produces sounds often referred to as “cold” or “hollow” relative to sounds produced through analog synthesis. [1] 1 | P a g e Analog Synthesis While digital synthesizers function by digital signal processing techniques, analog synthesizers employ a technique called analog synthesis. In this process, actual voltage signals are created and manipulated by analog circuits that function together. Unlike digital circuits that deal with a predetermined number of possible states, analog-based systems have a continuously variable signal. Analog Synthesizers can be sorted into two categories: keyboard-based and non-keyboard based. Keyboard-Based Analog Synths The synthesis process for keyboard-based synthesizers can be broken down into three basic components: Voltage-Controlled Oscillators generate the initial signal. The signal’s frequency (that determines which musical note you hear) is controlled by which key is pressed. Voltage-Controlled Filters edit the harmonic content of the signal generated by the oscillators. They typically do this by removing either the high-frequency harmonic range or the low-frequency range. Voltage-Controlled Amplifiers prepare the signal to be outputted as a sound wave by amplifying it by an amount set by the user. For some synthesizers, this stage also includes circuits that add special effects to the signal. Non-Keyboard Based Synths Many analog synthesizers operate without using a traditional piano keyboard to control the output. A classic example of this type of synthesizer is the Theremin, with which the user makes no physical contact (the Theremin is controlled by users contacting the electromagnetic field that surrounds it). [2] On the most basic level, many synthesizers of this type also rely on oscillators, filter and amplifiers to produce the sound. Unlike their keyboard-based counterparts, these synthesizers cannot be replicated by digital synthesizers. This is because digital synthesizers require a user interface with a finite number of possible The Theremin: a sound synthesizer without a keyboard Source: electronics.howstuffworks.com user inputs. 2 | P a g e Comparing Analog to Digital Digital synthesizers can closely approximate many analog synthesizers, but the recent resurgence of analog instruments indicates that this approximation is far from perfect. Unlike digital circuits, analog circuits are impacted by a wide variety of conditions like room temperature, humidity, and slight imperfections within the electronics. All of these conditions add sonic texture to the synthesizer’s output, making it sound “warmer” than many digital synthesizers. Conclusion All in all, the analog synthesizer consists of several different parts that work together to produce sound. Oscillators generate signals that are altered by Voltage-Controlled Filters, and the amplifiers boost the altered signals for output as sound waves. The arrangement of all of these parts makes the instrument unlike any other, in spite of efforts to digitally replicate it. References [1] Turner, T. Analog Vs Digital Synthesizers: A Basic Comparison. 2009. [online]. Available: http://voices.yahoo.com/analog-vs-digital-synthesizers-basic-comparison-3884938.html?cat=15 [2] Grimes, G. How a Theremin Works. [online]. Available: http://electronics.howstuffworks.com/gadgets/audio-music/theremin.htm 3 | P a g e .