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The Welcome to AWE guide contains instructions for basic usage of modules in Designer to create synthesized sounds from scratch. The example will contain instructions for creating oscillators, modulating pitch with a second oscillator, adding an envelope, pitch randomizer, filter LFO, Delay, and effects like Reverb or Amp simulator.

The materials referred to in this document can be downloaded HERE finished design and files used for this tutorial are attached below:

If you are having difficulty downloading the materials or have other questions, please email se@dspconcepts.com

Overview of the design

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Within the “WelcomeToAWE_SynthTutorial.awd” there are 7 sections or steps to creating the signal flow. In a blank design, there will always be an input and output audio pin labeled “SYS_in” and “SYS_out”. Since all audio is generated from within the design, there is no need for the input pin to bring in audio. We stop the input pin from sending audio by connecting the Type Convert following it, to a Sink module. New modules can be searched for and dragged onto the canvas from the module browser on the left side of the Designer window. Any module with blue in or out pins needs to be connected with a wire for the design to run. The Sink module allows this connection while discarding the input data. We also set block size of the design by right clicking the input pin module, selecting “View Properties”, clicking the build tab in the properties window, and changing the block size from 32 to 256.

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Step 1: Basic Oscillator

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This is the beginning of the signal flow. A periodic function generator module is used to output a continuous carrier signal of constant amplitude. A General Purpose Scaler is used to adjust the gain. At the end of this step if you run the design, you should hear a single pitch of a waveform you designate.

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Step 2: Frequency Modulation

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By adding a 2nd, modulating frequency to the main carrier frequency, we create vibrato in the low frequency range, or begin adding harmonics in the audio range. This is the foundation for tons of interesting synthesizer sounds.

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To remotely control the oscillator from step 1, we use a ParamSet module. We do this by connecting the output from our FM subsystem to the input pin of ParamSet, and setting the modVar parameter in the Arguments tab to “Oscillator.freq” as it’s the name and parameter of the module we want to control.

Step 3: Envelope LFO

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Without an envolope, an oscillator would have no way of starting or stopping. When you press a key on a synthesizer, you are essentially opening and closing a gate for that oscillator. In its most basic form, an envelope would look like a square wave, but allow time for the gate to slowly open or close and you've created an "attack" time and "release" time. Other envelope stages include "sustain" and "decay".

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In this example we want to control the “attack” and “release” stages of the envelope. Starting with a PeriodicFunctionGen module, we set it to output a square wave at 2 Hz with an amplitude of 1. This will be used to trigger the attack and release stages one time each per second. By using 2 LogicCompareConst modules, we can set one to output “true” if the oscillator equals 1, and the other to output “true” if the output equals 0. Next we route 2 ParamSet modules to the EnvelopeGenerator.startAttack and EnvelopeGenerator.startRelease parameters.We’ve initially set the attack times and release times to 5ms and 50ms respectively, but adjusting these values can yield interesting results!

Step 4: Pitch Randomizer

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Here we create a periodically randomized whole-number multiple of the fundamental frequency of our synth. Whole number multiples of a frequency replicate the harmonic series, a naturally occurring sequence of pitches from which all music is formed.

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Lastly, connect the output of the number generator to the frequency modulation (step 2) subsystem with a multiplexor to be able to toggle pitch randomization on or off.

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Step 5: Filter LFO

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By using a sine wave oscillator at a low frequency of just a few hertz, we can use the signal to control the cutoff of a low-pass filter. This subsystem was given two inputs to provide a bypass path.

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Begin by inserting a Second Order Filter module set to “VariableQLPF” in the signal path. Using the same technique as in Step 2, we remotely oscillate the cutoff frequency of the low pass filter between 200Hz and 5800Hz (3000Hz +/- 2800).

Step 6: Delay Feedback

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To create an echo effect, we must add a feedback wire downstream of a delay module. As the signal feeding back is added back into the original “dry” signal, we use a scaler to control how much of that original signal feeds back.

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Step 7: Reverb and Amp Simulator

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Additional effects are created by loading preset coefficients into a long FIR filter.

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