Frequency shifting

An audio processing technique that moves sounds from one frequency range to another, typically shifting high-frequency sounds into lower frequency ranges that a person with high-frequency hearing loss can still perceive. Many common hearing loss patterns affect high frequencies first, making consonant sounds (s, f, th), bird song, alarms, and certain musical tones inaudible. Frequency shifting preserves the presence of these sounds by transposing them into the listener's audible range, though the shifted sounds will have a different perceived quality than the original. In accessibility, frequency shifting is used in hearing aids, cochlear implant processors, and increasingly in software-based audio modification tools for VR, gaming, and media, where individual sound sources can be selectively shifted without affecting other audio.