Otonality/Utonality/3rd Bridge Posters by Yuri Landman

Three beautiful posters by instrument builder Yuri Landman for music theory reference -  Otonality - From Harry Partch's theory and familiar to anyone who has studied Just Intonation. Otonality is a collection of pitches which can be expressed in ratios, expressing their relationship to the fixed tone, that have equal denominators. For example, 1/1, 5/4, and 3/2 (just major chord) form an otonality because they can be written as 4/4, 5/4, 6/4. Utonality - Also from Harry Partch - The inversion is the inversion of an Otonality: it is formed by building the same interval sequence as that of an Otonality downward from the root of the chord, rather than upward. The analogy, in this case, is not to the harmonic series but to the subharmonic, or undertone series. 3rd bridge - Stringed instruments which have a 3rd bridge such as the Jazzmasters used by Glenn Branca, Sonic Youth and Yuri Landman's Caterpillar Drum Guitar. If these ideas are new to you, here's why they might be of interest - W