What is Binaural beats?
A '''binaural beat''' is an [[auditory illusion]]. It is [[Perception|perceived]] when two different pure-tone [[sine wave]]s are presented to a [[hearing|listener]], one tone to each ear.<ref>Both tones have [[Frequency|frequencies]] lower than 1500&nbsp;Hz, with less than a 40&nbsp;Hz difference between them.</ref> For example, if a 530&nbsp;Hz pure [[Pitch (music)|tone]] is presented to a subject's right ear, while a 520&nbsp;Hz pure tone is presented to the subject's left ear, the listener will perceive the [[illusion]] of a third tone. The third sound is called a binaural beat, and in this example would have a perceived pitch correlating to a frequency of 10&nbsp;Hz, that being the difference between the 530&nbsp;Hz and 520&nbsp;Hz pure tones presented to each ear.<ref>{{Cite web|url=http://breakthroughpsychologyprogram.com/binaural-beats|title=Binaural Beats|website=Psychology, Neuroleadership, & Neurofeedback|language=en|access-date=2018-08-26}}{{Dead link|date=June 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name=Oster/> They may help people with pain when they are in hospital.<ref>[https://www.ncbi.nlm.nih.gov/pubmed/10460529 Hemispheric-synchronisation during anaesthesia: a double-blind randomised trial using audiotapes for intra-operative nociception control], Jan 2000, Kliempt, Ruta, Ogston, Landeck & Martay</ref> Some people use binaural beats to help them [[sleep]], [[meditation|meditate]] or have [[Out of body experience|out of body experiences]].<ref>[http://www.scientificexploration.org/journal/jse_11_3_atwater.pdf Accessing anomalous states of consciousness with a binaural beat technology] {{Webarchive|url=https://web.archive.org/web/20120507033254/http://www.scientificexploration.org/journal/jse_11_3_atwater.pdf|date=2012-05-07}} ''Journal of Scientific Exploration''. '''1''', (3) pp. 263-274, 1997</ref> There are computer programs and smartphone programs that make binaural beats. Many of the claims are not verified at present.<ref>Wahbeh H. ''et al'' 2007. Binaural beat