Quarter-comma meantone each kind, a perfect fifth of meantone contains four diatonic and three chromatic semitones, and an octave seven diatonic and five chromatic semitones, it follows that: Thus, in Pythagorean tuning, where sequences of just fifths (frequency ratio 3:2) and octaves are used to produce the other intervals, a whole tone is and a major third is An interval of a seventeenth, consisting of sixteen diatonic and twelve chromatic semitones, such as the interval from D to F, can be equivalently obtained using either This large interval of a seventeenth contains staff positions. In Pythagorean tuning, the size of a seventeenth
Octave illusion Lamminmaki et al. (2012) in MEG studies provide an explanation of the illusion at the neurophysiological level that is in accordance with Deutsch’s two-channel model. Octave illusion The octave illusion is an auditory illusion discovered by Diana Deutsch in 1973. It is produced when two tones that are an octave apart are repeatedly played in alternation ("high-low-high-low") through stereo headphones. The same sequence is played to both ears simultaneously; however when the right ear receives the high tone, the left ear receives the low tone, and conversely. Instead of hearing two alternating pitches, most subjects instead hear a single tone