Welcome to the Seystertron, a digital synthesizer programmed entirely in Java. I suggest that you hook it up to an amp that goes to eleven and crank it! Your neighbors will appreciate it. If you want to play with the synth right now, the Try the Synthesizer section has a quick guide to using it.

Synthesizers are at the core of electronic music. Instead of producing sound physically, like acoustic mucial instruments or electric guitars and pianos, or producing sound by playing recorded samples, like a digital piano, they produce sound with electronic circuits. The first synthesizers used analog electronics. The basic production of sound was done with oscillators, circuits that output a periodic waveform, such as a sine wave or square wave. This waveform can be output to a speaker, and you have electronic music!

Of course, discerning listeners will probably want to hear something a bit more interesting (and perhaps less obnoxious) than a single waveform. Waveforms from several oscillators can be mixed (added) together to create a more complex waveform. But making an interesting sound sound this way is still difficult. The most popular synthesis model is known as subtractive synthesis. You begin with a small number of waveforms. Most synthesizers use two oscillators, though some use three or four. Generally, these oscillators can generate waveforms such as square waves and saw waves that have a lot of frequency components. This signal is put through a filter that can "subtract" frequency components and is the key component in a subtractive synthesizer. The Seystertron has two types of filters, a low-pass filter (one of the most useful types of filters), which filters out high frequencies, and a high-pass filter, which filters out low frequencies. In analog synthesizers, these filters were designed using capacitors and inductors. Finally, you can process this basic signals through effects to tweak the sound. This signal path, along with mechanisms for changing effects parameters with time are the basis of a subractive synthesizer.

Unfortunately, analog electronics are notoriously difficult to work with. Designing them involves at least a little bit of black magic, and they are prone to failure. In addition, analog oscillators fall out of tune, requiring them to be tuned before performances. Eventually, synthesizers made the transition to digital electronics. In digital synthesizers, the sound is no longer represented as an analog signal. It is stored instead as digital samples, the way sound is stored on a CD. Analog filters are replaced with digital processors that mathematically simulate filter effects. At the very end of the signal path, the digital sound is converted to an analog signal so that it can be output to speakers. Digital electronics are extremely reliable and never fall out tune. Partly for these reasons, but mostly because it is not actually possible to program analog electronics on a digital computer, the Seystertron is a digital synthesizer.