Introduction To Audio Distortion

We've all been there—a live music concert, the exhilarating moment when your favorite artist strikes a chord that resonates deep within your soul. Overwhelmed by the urge to capture this magical experience, you instinctively reach for your smartphone, hoping to preserve the memory for later enjoyment or to share it with loved ones. Yet, when you eventually listen to the recording, disappointment washes over you as you realize it no longer captures the essence of that enchanting performance. This phenomenon, my friends, is known as audio distortion—a complex audio challenge that we are about to unravel.

Audio distortion can be caused by a variety of factors. In this article, we will focus on electrical distortion. The extent of this distortion varies based on the intensity of the incoming sound pressure. A major contributor to electrical distortion occurs when the audio signal exceeds the microphone's output voltage limit, leading to a phenomenon known as clipping. Every microphone is powered by a supply voltage, or voltage rail. When the microphone captures sound, it generates an electrical signal which is amplified by its internal circuitry. The louder the sound into the microphone is, the larger the electrical output is. However, the output of the microphone can never exceed the voltage rail. When the sound captured is amplified to a level larger than the voltage rail, it is cut, gravely impacting the quality of the audio signal and creating audio distortion. The offending noise is either lost or transformed into sharp, square shapes that deviate from its original waveform.

Clipping Visual Representation

To illustrate this audio distortion, let us examine a graph showcasing the phenomenon of clipping. Below is a graph showing a microphone output when capturing subject to a typical sound. The output of the microphone falls within the voltage rails of the microphone, resulting in zero clipping.

In contrast, the graph below shows the microphone output when subject to a very loud sound, resulting in clipping.

This visual representation exemplifies the disparity between a waveform within the microphone's voltage rails, devoid of any clipping, and a graph depicting sound pressure levels that exceed the microphone’s output limits, resulting in clipping. As portions of the sound wave reach the microphone’s limit, the audio in that portion saturates and is held at a constant level. This audio distortion can be truly jarring, as the next section shows.

Clipping Audible Representation

To truly grasp the impact of distortion, take a moment to listen to this audio clip. We will gradually increase the volume until it hits its limit and succumbs to distortion, providing you with a firsthand experience of its disruptive nature.

Audio clip of undesirable distortion

In most cases, audio distortion is an undesirable element, as exemplified by the aforementioned scenario of recording audio at a live music concert. However, there are instances where audio distortion becomes a sought-after effect, particularly within the realm of music. Let's delve into the world of electric guitars for a moment. Have you ever plucked the strings of an unamplified guitar? The sound produced is smooth and quiet. However, when connected to an amplifier with various effects, the guitar undergoes a transformative journey, emanating a gritty and captivating sound that can reverberate throughout a vast stage. This deliberate use of audio distortion allows musicians to create a unique sonic experience. Similarly, in genres like dubstep, synthesizers are manipulated to amplify harmonics and generate distinctive, distorted sounds. Take a moment to listen to this audio clip of a guitar using distortion as a desired effect.

Audio clip of desirable distortion

Through the interactive chart, you can immerse yourself in the experience of listening to audio distortion while simultaneously observing the corresponding changes in the waveform. As you drag the slider to the right, the clipping effect of the audio sine wave increases, adding to the overall auditory impact. To listen to the clipping effect while moving the slider, click "Play Sound". To stop the sound, click "Stop Sound".