Creative Forensic Services

Auditory illusions:

Auditory illusions, which are often caused by compressed audio artifacts in lossy audio files, can have a big effect on how we think the sound quality is. Lossy audio compression techniques are often used to shrink the file size of audio recordings without changing how the sound sounds to the human ear. However, these techniques can cause different kinds of auditory artifacts that can change how we hear the sound.

Quantization noise is one of the most common types of artifacts that can be heard when lossy audio compression is used. This is caused by the reduction in the bit depth of the audio file, which reduces the number of possible amplitude values that can be represented. This can result in a loss of detail and a "grainy" or "fuzzy" sound quality, which can be perceived as an auditory illusion.

Another type of auditory artifact that can be introduced by lossy audio compression is called pre-echo. This happens when the sound signal before a transient sound, like a drum hit or cymbal crash, is compressed more than the transient itself. This can make a faint, ghostly sound that seems to come before the real sound, giving the impression of a backwards echo.

Lossy audio compression can also cause spectral smearing or phase distortion, which are types of artifacts that can be heard. This happens when the original sound waveform is changed in a way that shifts or distorts the frequency parts of the sound. This can result in a loss of clarity and definition in the sound, leading to the auditory illusion of a muddied or distorted sound.

Aside from these specific types of auditory artifacts, lossy audio compression can also change the way we hear sound in more subtle ways. For example, high-frequency content may be lowered or taken away, which makes the sound less clear and full. Similarly, low-frequency content may be compressed or filtered out, resulting in a loss of warmth and depth in the sound.

Despite these potential issues, lossy audio compression remains a popular and widely used technique for reducing the file size of audio recordings. It is important to remember that the effects of auditory illusions caused by compressed audio artifacts can vary depending on the specific compression technique used, the quality of the original recording, and the listening environment.

In conclusion, auditory illusions caused by compressed audio artifacts in lossy audio files can have a significant impact on our perception of sound quality. These artifacts can result in a loss of detail, clarity, and definition in the sound, and can create auditory illusions such as quantization noise, pre-echo, spectral smearing, and more. Even though lossy audio compression is still a popular and effective way to reduce the file size of audio recordings, it is important to be aware of these potential problems and take steps to make sure they don't affect how we listen.