#AudioEffects #C++

Audio effects play a crucial role in enhancing the sound quality of audio recordings and live performances. One popular audio effect is the plate reverb, which simulates the sound of an audio signal bouncing off a large metal plate. In this tech blog, we will explore how to implement plate reverbs in C++.

What is Plate Reverb?

Plate reverb is a type of artificial reverb that was commonly used in audio recording studios during the analog era. It consists of a large metal plate suspended within a frame. The audio signal is sent through a transducer that vibrates the plate, creating sound reflections. These reflections are then picked up by a pickup transducer and mixed with the original signal, resulting in a rich and spacious reverberation effect.

Implementing Plate Reverbs in C++

To implement plate reverbs in C++, we can use digital signal processing (DSP) techniques. Here is an example code snippet that demonstrates a basic plate reverb algorithm:

// Include necessary libraries and headers

#define PLATE_SIZE 2048
#define PICKUP_POSITION 0.25
#define DAMPING_FACTOR 0.97

float plate[PLATE_SIZE] = {0};

// Function to process audio input
void processAudioInput(float* input, float gain)
{  
    for (int i = PLATE_SIZE - 1; i >= 0; i--)
    {
        plate[i] = (plate[i] + plate[i - 1]) * DAMPING_FACTOR;
    }
    
    float pickupSample = plate[PICKUP_POSITION * PLATE_SIZE];
    
    for (int i = 0; i < PLATE_SIZE; i++)
    {
        plate[i] += input[i] + gain * pickupSample;
    }
}

// Example usage within an audio processing loop
int main()
{
    // Setup audio input and output
    
    while (true)
    {
        // Read audio input
        
        // Apply plate reverb
        processAudioInput(input, 0.5);
        
        // Write audio output
    }
    
    return 0;
}

Customizing Plate Reverb Effects

You can customize the plate reverb effect by tweaking parameters such as the plate size, pickup position, and damping factor. In the provided code snippet, PLATE_SIZE defines the size of the plate buffer, PICKUP_POSITION determines the pickup transducer’s location on the plate (ranging from 0 to 1), and DAMPING_FACTOR controls the decay rate of the reverb.

You can experiment with different values to achieve a desired reverb sound. Additionally, you can extend this basic implementation by incorporating additional DSP techniques, such as pre-delay or high-pass filtering, to further enhance the plate reverb effect.

Conclusion

Plate reverbs offer a unique and recognizable reverb sound that can greatly enhance audio recordings and live performances. By implementing plate reverbs in C++, you can create your own custom audio effects and integrate them into digital audio applications. The provided code snippet serves as a starting point, but feel free to explore and experiment further to achieve the desired reverb sound.