In essence, SpectroChord V1.0 is a chord identifier for up to five musical notes played simultaneously or in quick
succession. It produces a spectrographic display that shows the association between the notes and each of one hundred and thirty two common chords. It saves the user considerable time spent searching tables of chords
when seeking that illusive match. SpectroChord has run successfully under Windows 95, 98 and XP.
How many chords should SpectroChord recognise? Potentially there are thousands of chords, but many musicians agree that, to Western ears, the triads and triads with added sixths, sevenths and ninths encompass the most useful. These may be subdivided into minor, major, augmented, diminished and dominant varieties as appropriate, yielding eleven
chord classes:- Minor, Major, Augmented, Minor 6th, Major 6th, Diminished 7th, Minor 7th, Dominant 7th, Major 7th, Dominant Minor 9th and Dominant 9th. A complete chord name also requires the tonic, or key-note name of which there are twelve
(A - G#). The products of key and chord class are 132 named chords, all recognised by SpectroChord.
The displayed spectrograph
SpectroChord gradates chords two ways; the first is by key-note (e.g. F#) with the chord classes appended as subdivisions; the second by chord class with keys as subdivisions. Ultimately both methods reveal the same information, but each convey different interesting impressions.
of chord classification adopted by SpectroChord depends on the relative positions of the key and its chord elements. Using the minor chord as an example; its elements are located nearest the key-note (the first note of the chord); the second note being three semitones above; the third at seven semitones above the key-note. This arrangement expressed as a binary number is 10,001,001 which equates to the octal number 211, whereas for the major chord it is 221. The numerical order of the eleven chord classes is shown below.