4 ms·
It's a phenomenon that happens to all waves, whether they are acoustic or electromagnetic. In fact, it's how your clock radio tunes to various stations. This pr
by iyulaev 13y ago
It's a phenomenon that happens to all waves, whether they are acoustic or electromagnetic. In fact, it's how your clock radio tunes to various stations. This property is a mathematical property of all waves, hence even when your brain mixes an electrical representation of the sound going into your left and right ears, you still get the effect.
- mdturnerphys 13y agoFor higher frequencies your auditory system doesn't retain the waveform information, so this doesn't happen.
- bigiain 13y agoI wonder if that's an evolutionary thing – somehow we evolved out the ability to retain phase difference information outside the frequencies where it's useful for stereo angular location? The "~1000Hz" upper limit is pretty close to a 1/4 wavelength for a "phased array" of two ears ~100mm apart. That'd make it pretty ideal for angular discrimination based on phase difference.
- apl 13y agoYou're pretty spot on here -- up to approximately 1500Hz, the auditory brain can make use of so-called inter-aural time differences which allow estimation of a given source's azimuth. After that, phase differences become ambiguous and the brain relies more heavily on inter-aural volume differences. http://en.wikipedia.org/wiki/Interaural_time_difference http://en.wikipedia.org/wiki/Interaural_time_difference