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| quote: | Originally posted by ibizzzaaa
NO 
It's more of the question of how all of the hardware produce all of those particular sounds and samples. |
There are many different ways of going about it depending on the module.
All analogue synthesizers generate their sounds from a Voltage Control Oscillator (VCO). Which for lack of a better description is a switch that changes the voltage in the circuit causing a variable, cyclical AC signal. The oscillation can be swtiched to a number of a basic waveforms, the most basic being a sinusoidal wave which has a fundamental frequency and absolutely no harmonics.
Sine wave oscillators and noise generators are the basis of pretty much all analogue drum machines and drum sounds. The infamous 808 for example derives all of its drum sounds by pitch bending sine wave oscillators and summing the signal with filtered white noise. All the high hats on an 808 are generated using unfiltered white noise, shaped using an amplifier envelope (which automatically fades it in/out). An 808 bass drum is a sine wave oscillator and a noise generator passed through a low pass resonant filter passed through a filter envelope stage which is passed through an amplifier envelope stage. Using the controls on the 808 you can vary the amount of filter resonance, the frequency of the sine wave oscillator (its pitch) and amplifier envelope attack and decay phases to shape the sound in several ways.
All of this is done electronically and the unit itself outputs a very small electrical AC signal. This signal is passed onto a transformer and then power amplifier stage which uses a massive voltage from a mains supply to increase the amplitude of the AC signal which is then fed to a speaker transducer. This transducer converts this variable AC signal into corresponding variations in air pressure which reach your ear and resonate with your ear drum. your brain perceives this stimulus as 'sound.'
A typical analogue synthesizer can have more than one oscillator and you can tune them against each other to produce more complicated cyclical waveforms. This your timbre.
you can sculpt your basic timbre using filters which are capacitors/inductors in series with the oscillator circuit that vary the reactance in the circuit thus attenuating the frequency of the AC signal above/below/at the point of a threshold point which you specify.
The basic signal chain for a simple analogue synth would be something like:
1) VCO (Voltage Control Oscillator) -> output
2) -> input VCF (Voltage Control Filter) -> output
3) -> input LFO (Low Frequency Oscillator) -> output
4) -> input Amplifier Envelope stage -> main output
CV/Gate is used to automatically trigger analogue synthesizers and form the basis of the sequencer.
CV/Gate has been replaced in digital audio with MIDI which is vastly more complex. It would take a thread in itself to explain what MIDI is adequately but at its most basic level it is a system of instructions that tell synthesizers what to do and when.
Since electronic dance music typically has fixed and very rigid timing, it was common to sequence many sounds instead of playing them by hand.
The TB-303 is a basic sequencer based synthesizer. You punch in the notes it should play on a 16 step grid. Then press play. It will automatically play this 16 step sequence and repeat it until you tell it to stop. During this time you may alter some of the synth variables such as its volume, its filter cutoff and resonance, its envelope attack and decay phase etc etc.
Last edited by Derivative on Sep-12-2007 at 12:46
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