# POW-R

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/POW-R
> Markdown URL: https://mediated.wiki/source/POW-R.md
> Source: https://en.wikipedia.org/wiki/POW-R
> Source revision: 1347779241
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

**POW-R** (Psychoacoustically Optimized Wordlength Reduction) is a set of commercial [dithering](/source/Dithering) and [noise shaping](/source/Noise_shaping) [algorithms](/source/Algorithm) used in [digital audio](/source/Digital_audio) [bit-depth](/source/Audio_bit_depth) [reduction](/source/Quantization_(signal_processing)). Developed by a [consortium](/source/Consortium) of four companies – *The POW-R Consortium* – the algorithms were first made available in 1999 in digital audio hardware products. POW-R is now licensed for use by many companies, particularly those in the [digital audio workstation](/source/Digital_audio_workstation) (DAW) arena, where it currently has significant [market share](/source/Market_share).

## History

POW-R was developed between 1997 and 1998 after an unfavorable change in the licensing terms of a leading bit-depth reduction algorithm of the time prompted some of its licensees to put together a consortium to develop a viable alternative algorithm.

Formed by four audio engineering companies: Lake Technology ([Dolby Labs](/source/Dolby_Labs)), Weiss Engineering, Millennia Media and Z-Systems, the consortium set out with the goal to create 'the most sonically transparent dithering algorithm possible'.[1]

In 1999, the first products containing POW-R were released by consortium companies.[1] Other companies became interested in using POW-R in their products, and the algorithms are now licensed to a number of leading DAW vendors including [Apple](/source/Apple_Inc.), Avid ([Digidesign](/source/Digidesign)), [Sonic Studio](/source/Sonic_Studio), Ableton,[2] Magix / Sequoia / Samplitude, and others.

## Reception

One of the first products to include POW-R was a hardware dithering unit from Weiss engineering; in a review of this product in 1999, [mastering](/source/Audio_mastering) engineer [Bob Katz](/source/Bob_Katz) spoke highly of the new algorithm declaring it 'an incredible achievement'.[1]

## Technical details

Technically, the entire POW-R suite is not noise shaping; rather, the original POW-R algorithm is based on narrow-band Nyquist dither, while other POW-R algorithms include noise shaping and white noise.[3] Unlike noise-shaping algorithms based on an ‘[Absolute threshold of hearing](/source/Absolute_threshold_of_hearing)’ model (i.e. the quietest sound that can be heard on otherwise silent conditions), POW-R has been designed to give optimal performance at normal listening levels. Here, optimal performance means maximizing the apparent [dynamic range](/source/Dynamic_range) of the resultant signal while simultaneously minimizing the audible effects of the dither and quantization noise which, if this is not achieved, are typically tonal in nature.[1]

Since noise audibility depends on the nature of the audio being processed, the POW-R algorithm is made available in three variants, optimized respectively for simple program such as [spoken word](/source/Spoken_word), limited dynamic range program such as rock music, and wide dynamic range program such as [orchestral music](/source/Orchestral_music).[3] Each algorithm moves the noise to those frequencies where its audible effect for the particular audio type is minimized. The graph to the right shows the [frequency response](/source/Frequency_response) of the orchestral music algorithm variant (POW-R3, a 9th order [filter](/source/Audio_filter)[1]).

## See also

- [Dithering](/source/Dithering)
- [Audio mastering](/source/Audio_mastering)
- [Noise shaping](/source/Noise_shaping)

## References

1. Katz, Bob. ["Weiss Engineering POW-R Dither"](http://www.proaudioreview.com/article/924). Retrieved 12 March 2009.

1. [Ableton ‘What’s new’](http://www.ableton.com/live-7-whats-new)

1. [Manufacturer's POW-R Data Sheet](http://www.weiss.ch/pow-r/documents/pow-r_brochure.pdf)

## Further reading

- Bobby Owsinski, Sally Englefried (2000). *The mastering engineer's handbook*. Mix Books. ISBN 0-87288-741-3.
- Bob Katz (2007). *Mastering Audio, Second Edition: The Art and the Science*. Focal Press. ISBN 978-0-240-80837-6.

---
Adapted from the Wikipedia article [POW-R](https://en.wikipedia.org/wiki/POW-R) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/POW-R?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.