"Echometry" (Ehos + Metron = Sound + Measure) The system that explains the interaction between the human brain and the sound of any melodic musical instrument of the Western Musical culture! An "Ear Training-Music Writing" tool, including both A-B-C-D-E-F-G and DO-RE-MI-FA-SOL-LA-TI teaching systems in ALL "Seven octaves." A "Signature Wheel" for all the Greek Modes, a perfect Vocal Instructor and an Instant Composer among other things, is literally under your fingertips! WELCOME and ENJOY it! Echometry took over 40 years to become reality and is the result of the aspirations of Alex A. Sioris, 65 years old who lives in Los Angeles, California and owns Marina Music Center for over 30 years. An accomplished musician and theorist, Alex created a NEW method of learning the secrets of the sound utilizing both VISUAL and AUDIO techniques thus MAKING MUSIC SIMPLE! Theory & Data A SOUND CELL is what you see on your screen. A clock-like circle with Twelve consecutive numbered sound positions usually referred to, as CHROMATIC Scale. Dividing TWELVE in groups is the primary technique of our brain in its effort to understand the MATH behind it! Three notes (out of 12) create what schools refer to as TRIADS Major-Minor-Diminished-Augmented-Suspended (5 total) are ALL triadic structures ! Add one more note and the TETRADS are created! Dominant seventh- minor sixth- minor 7 b5- Maj 7...(36 total) are such tetrads! Add one more and the Pentatonic (5/12) Scale, most popular along with the Diatonic(7/12)- is created! This App is the tool to study all: Triads-Pentatonic-Diatonic scales and can instantly transpose any scale or mode on a variety of instruments provided! The different names (Ionian, Dorian, Phrygian, etc.) are what Music Schools call Diatonic Scales or Modes. They are either Heptatonic (7/12) or Pentatonic (5/12). Add 7 + 5 (Heptatonic + Pentatonic) and the mother of ALL scales, the Chromatic scale, is created!