SOUND SYNTHESIS

 1.

This is the block diagram for long period ascending arpeggios of a sine wave. If we change the Source Oscillator from Ramp to Sine the arpeggios will follow an ascending – descending curve.

                  

                   

 

2.

This is a block diagram for the wah-wah effect. The amount of the modulation is controlled by the note you play on a keyboard using the MIDI/CV module.  The rate of the modulation can be controlled by the LFO.            

            

    

3.

This is a block diagram for the generation of wind or sea sounds. The patch below generates wind sounds using a fast envelope attack. If we would like to synthesize sea sounds, then we would change the wave of the oscillator to white noise, raise the filter frequency and make the attack very slow.

 

           

            

4.

There are many different ways to synthesize a bell.  Ring modulation can deliver very good results, but I have noticed that you can have more realistic results with Frequency Modulation.

                    

 

   

5.

We can double the frequency of a sine wave by using a Ring Modulator. As we know already, if we feed into a RM two sine waves (f1,f2), it will produce frequencies at f1 – f2 and f1 + f2. If the sine waves have the same frequency then f1 – f2 = 0 and f1 + f2 = 2f (double the frequency). A MIDI/CV module connected to a keyboard ensures that both OSC work at the same frequency.

                          

 

 

6.

 

A typical flute sound produces only odd number of harmonics and is also characterized by the initial breath chiff in the beginning of the sound. Therefore, one way to construct a flute sound would be to use two oscillators, one with a triangle waveform producing the odd harmonics steady sound and a second with white noise to produce the initial chiff. The triangle oscillator must have a fast envelope attack with a medium sustain time and fast release. The white noise generator must also have a fast attack envelope time, but it should only be noticeable at the beginning of the flute sound, therefore the sustain time must be very small.

 

 

 7.

We can create tremolo by modulating the amplitude of a desirable sound with a Low Frequency Oscillator. Usually, the LFO should take values between 3-6Hz in order to produce a tremolo a tremolo sound and not sidebands. In the patch below, the amount of modulation [tremolo] is controlled by the VCA, while the rate of modulation [tremolo rate] is controlled by the frequency of the LFO.

 8.

There are different ways to produce random pitches in a subtractive synthesizer, but the most effective I found, is to use a white noise generator as a way to produce randomness. The following patch uses a S/H module, controlled by two LFOs to produce a continuous random pitch output. The rate of random frequencies can be controlled by the frequency of the Pulse LFO. 

9.

 

The following patch demonstrates a simple tone burst using a sine wave. A Low Frequency Oscillator with a square waveform is used to ‘open’ and ‘close’ the VCA output. The rate of the tone burst can be controlled by the frequency of the LFO.

 

 

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