Phasers are a popular audio effect used to create unique sound textures by introducing frequency notches or peaks into the audio signal. In this article, we will explore how to implement audio effects using phasers in C++.

What is a Phaser?

A phaser is an audio effect that creates a sweeping, swirling sound by splitting the audio signal into two paths and modulating the phase of one path relative to the other. By altering the phase relationship between the paths, phasers introduce constructive or destructive interference, resulting in notches or peaks in the frequency spectrum.

Implementing a Phaser Effect

To implement a phaser effect in C++, we need to manipulate the phase of the audio signal. Here is an example code snippet that demonstrates a basic phaser implementation:

#include <cmath>

class Phaser {
private:
  double rate;
  double phase;
  double depth;
  double feedback;
  
public:
  Phaser(double rate, double depth, double feedback) {
    this->rate = rate;
    this->phase = 0.0;
    this->depth = depth;
    this->feedback = feedback;
  }
  
  void process(double* buffer, int bufferSize) {
    double phaseIncrement = 2.0 * M_PI * rate;
    
    for (int i = 0; i < bufferSize; i++) {
      double wet = buffer[i] + feedback * phase;
      double dry = buffer[i];
      
      buffer[i] = (1.0 - depth) * dry + depth * wet;
      
      phase += phaseIncrement;
      if (phase >= 2.0 * M_PI) {
        phase -= 2.0 * M_PI;
      }
    }
  }
};

Here, we define a Phaser class with rate, depth, and feedback parameters. The process function applies the phaser effect to an input audio buffer. The phase variable keeps track of the current phase position, which is incremented by the phaseIncrement value for each sample.

Using the Phaser Effect

To use the phaser effect in your C++ audio project, you can instantiate the Phaser class and call the process function on your audio buffer. Here’s an example of how you can use it:

// Create an instance of the Phaser effect
Phaser phaser(0.3, 0.5, 0.4);

Conclusion

Implementing audio effects, such as phasers, in C++ can enhance the sound of your applications or projects. By manipulating phase relationships, phasers create interesting sound textures. The code snippet provided in this article serves as a starting point for implementing a basic phaser effect in C++.