Encyclopedia > Psychoacoustic model

  Article Content

Psychoacoustic model

The psychoacoustic model provides for high quality lossy signal compression by describing which parts of a given digital audio signal can be removed (or aggressively compressed) safely -- that is, without significant losses in the quality of the sound. It explains, for example, how a sharp clap of the hands might seem painfully loud in a quiet library, but hardly noticeable after a car backfires on a busy, urban street. It might seem as if this provides little benefit to the overall compression ratio, but psychoacoustic profiling routinely leads to compressed music files that are 10 to 12 times smaller than high quality original masters with very little discernible loss in quality. Such compression is a feature of MP3,MUSICAM[?] (used in digital radio -- DAB, or DR[?] --in Europe and elsewhere, based on Eureka 147), and the compression used in MiniDisc, to mention a few common audio compression standards.

Psychoacoustics is based heavily on human anatomy, especially the ear's limitations in perceiving sound. Among these limitations are:

Given that the ear will not be at peak perceptive capacity when dealing with these limitations, a compression algorithm can assign those sounds outside the range of human hearing a lower priority; by carefully shifting bits away from the unimportant components and toward the important ones, the algorithm ensures that the sounds the listener hears most clearly are of the highest quality.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Northampton, Suffolk County, New York

... 20.3% of all households are made up of individuals and 5.7% have someone living alone who is 65 years of age or older. The average household size is 2.96 and the average ...

 
 
 
This page was created in 57.6 ms