means creating your own sounds
This is an absolute
beginner's guide to
a little think about how to create sound
To create realistic musical sounds two sorts of generators are needed
oscillators to produce the basic waveform and
The oscillating medium in many woodwind instruments is a reed; for brass instruments and the didgeridoo the oscillating medium is the player's buzzing lips. These create standing waves.
What types of waves are needed to synthesize brass sounds? What else is needed apart from those waves? Listen to these real brass instruments and describe their timbre.
1 Basic waveforms
Sine wave: simply the fundamental with no harmonics. Pure. Used on its own for creating the sound of a whistle or a test tone.
Sawtooth or Ramp waves are what you get if you add up all the harmonics with amplitudes equal to 1/N where N is the number of the harmonic. Rich, bright.
Square waves are what you get by adding only the odd numbered harmonics with amplitudes equal to 1/n. Hollow, woody.
So, Sawtooth or Ramp contain all harmonics whereas Square waves contain only odd numbered harmonics.
Triangle waves are what you get if you add only the odd harmonics at decreasing intensity. Duller than square wave.
Pulse waves: A square wave is a pulse wave with a 50% 'duty cycle' or a 50:50 ratio. If you think about the figure of a sine wave it is above the centre line for half of the time and below it for the other half . A square wave does the same. Synthesisers that generate pulse waves allow you to change the duty cycle. This in turn changes the harmonic content. A square wave with it's 50% duty cycle has a hollow, clarinet like tone, a pulse wave with, for example, a 5% duty cycle has a more nasal, double reed like tone. Nasal, spikey.
White noise is a hiss like you hear from a radio or TV when it is between stations. White noise is what you get when you add all audible frequencies together with equal energy. Its amplitude is constant throughout the audible frequency range. High-pitched hiss.
noise is what you get if you add all frequencies with
equal energy per octave. It sounds like white noise with the bass end
enhanced. It is random noise that has the same power in each octave.
are three main types of synthesis
Subtractive is where a rich source is filtered and enveloped. A waveshape is chosen and has filter and amplitude envelopes applied to it. A filter cuts down the number of harmonics and overtones in a waveform. Each basic waveform has its own character.
Additive is where waveforms (usually sine) are added together. Each has its own amplitude (loudness) envelope. Basic as well as complex waveshapes can be created by adding the relevant harmonic frequencies at the correct loudnesses. An envelope generator for each oscillator allows for tonal changes over time.
refers to FM (frequency modulation) and to synthesis
taken from samples of sound.
you some idea of how
musicians create sounds electronically.