When it comes to audio processing, de-essers play a crucial role in reducing harsh sibilant sounds in vocals or other audio recordings. In this tutorial, we will explore how to implement de-essers in C++ to enhance the quality of audio.

What is a De-esser?

A de-esser is an audio effect commonly used in audio post-production and live sound engineering. Its primary function is to reduce or remove the excessive “s” and “sh” sounds, also known as sibilance, from vocal tracks or any audio recordings.

Understanding the De-essing Process

The de-essing process involves analyzing the audio signal, identifying the frequency range where the sibilance occurs, and attenuating those frequencies while leaving the rest of the audio intact. This is achieved using a combination of filtering and dynamic gain reduction techniques.

Implementing a Simple De-esser Algorithm

Let’s implement a basic de-esser algorithm in C++, which will focus on attenuating the sibilant frequencies in an audio signal. Here’s an example code snippet that illustrates the implementation:

// Include necessary libraries
#include <iostream>
#include <cmath>

// De-esser parameters
float threshold = -16.0f; // Threshold in dB
float ratio = 2.5f; // Compression ratio
float detectionRange = 2000.0f; // Frequency range to detect sibilance
float attackTime = 0.01f; // Attack time in seconds
float releaseTime = 0.1f; // Release time in seconds

// De-esser function
void deEsser(float* audioBuffer, int numSamples, float sampleRate) {
    float detectionThreshold = std::pow(10.0f, threshold / 20.0f);
    float detectionFactor = sampleRate / detectionRange;
    float attackCoeff = std::exp(-1.0f / (attackTime * sampleRate));
    float releaseCoeff = std::exp(-1.0f / (releaseTime * sampleRate));
    float gain = 1.0f;

    for (int i = 0; i < numSamples; i++) {
        float sampleAbs = std::abs(audioBuffer[i]);
        if (sampleAbs >= detectionThreshold) {
            float reduction = (sampleAbs - detectionThreshold) * (ratio - 1.0f) / sampleAbs;
            gain = std::max(gain * reduction, gain * releaseCoeff);
        } else {
            gain *= attackCoeff;
        }

        audioBuffer[i] *= gain;
    }
}

int main() {
    // Load audio file or generate synthetic audio signal
    // ...

    // Apply de-esser
    deEsser(audioBuffer, numSamples, sampleRate);

    // Save processed audio file or play the audio
    // ...

    return 0;
}

Customizing the De-esser Algorithm

The example code above demonstrates a simple de-esser algorithm, but you can customize it further based on your requirements. You can experiment with different parameters such as threshold, ratio, attack time, and release time to achieve the desired audio effect. Additionally, you can expand the algorithm to incorporate more advanced techniques like multiband processing or sidechain filtering.

Conclusion

Implementing de-essers in C++ allows you to enhance the quality of audio recordings by reducing or removing sibilant frequencies. By customizing the de-esser algorithm, you can fine-tune the audio effect according to your preferences and requirements. Whether you’re working on audio post-production, live sound engineering, or any other audio-related application, de-essers prove to be an essential tool in your toolbox.

Try implementing the de-esser algorithm in your audio processing project and unleash its potential to enhance vocals and other audio recordings!

#AudioProcessing #Cplusplus