| Introduction | 2 |
| Section 1. Pitch scales as a level of music perception | 6 |
| Section 2. Optimal timbres and scales | 14 |
| Section 3. Well tempered 19-tone scale | 22 |
| Conclusion | 38 |
| Annex 1. Information carried by a change in a distribution function | 41 |
| Annex 2. A notation sysytem for 19-tone music | 43 |
| Annex 3. Piano keyboard structure for the 19-tone system | 46 |
| Charts | 47 |
| Table 1. τ-timbres | 52 |
| Table 2. Optimal timbres | 47 |
