Equalizers can be one of the most important tools to any audio engineer, and especially an Audio Forensic Expert. There are many different types of equalizers with different capabilities, but the core functions are always the same. Equalizers allow the user to increase or decrease the level of different frequency ranges or ‘frequency bands.’ Each frequency band is typically marked by its center frequency, while the width of the band will vary between different equalizers. Some equalizers even allow the frequency band and the width to be adjusted.
Having these controls at your disposal when performing an audio enhancement is crucial. Noise and other extraneous frequency content is usually the biggest issue with audio recordings. Equalizers and filters offer the ability to remove narrow ranges of frequencies so that these noises can, for the most part, be removed from the recording while leaving other frequencies untouched.
When using an equalizer, it’s important to be careful boosting and cutting different ranges. Sometimes removing a certain noise may sound helpful at first, but there could also be a lot of important voice content in the same range. Making the proper adjustments with an equalizer requires both experience with the equipment, critical listening skills, and a lot of trial and error. The more time you spend working with audio and equalizers, the more familiar you will become with different frequency ranges and how to best go about improving the quality of different recordings.