Frequently Asked Questions

Short answers to what the atlas counts, what it leaves out, and how to read its tables.

Questions, Answered

Why these seven families?
Each one is a set of seven notes that a published source treats as a parent: the source names all seven of its modes. The diatonic modes, the ascending melodic minor, the harmonic minor, the harmonic major and the double harmonic are laid out that way in the same reference, and the Neapolitan major and minor in one of their own. A family no source lays out that way is not declared here.
What counts as one altered degree?
One note of a mode, other than its root, moved a semitone up or down, with the result still seven notes in the same order. Ionian with its fourth raised is Lydian: one altered degree. Ionian with its second and sixth lowered is the double harmonic: two, so the two are not neighbours, though the route between them stops at the harmonic major.
Where do the mode names come from?
From the table in each family’s source, copied as printed, with the flat, sharp and natural signs written as b, # and the word natural. Where a source prints several names for one mode, the family page shows them all and the other tables use the first. If a source left a rotation unnamed, this site would leave it unnamed too.
How do I read an interval vector?
As six counts: how many pairs of notes in the family lie one, two, three, four, five and six semitones apart, measured the shorter way round. A seven-note set has twenty-one pairs, so the six counts always add up to twenty-one. Every mode of a family has the same vector, because rotating a set shifts where it starts and changes no distance inside it.
What does it mean for a family to be its own mirror?
Reflect a mode around its root, so a degree four semitones up becomes one four semitones down, and see which mode you get. For four of the families every reflection lands back inside the same family; the harmonic minor and harmonic major land on each other; and the Neapolitan minor lands on a set no family here declares.
Why is there no page for each scale?
Because the network already has one: the theory site gives every common scale and mode a page of its own. This site keeps to the relations between them, so a scale appears here only as a row in its family and as one end of its neighbours.
Can I link to a mode I picked on the neighbours page?
No. The mode you stand on is chosen in your browser and never becomes part of a web address, so there is one neighbours page, not one per mode. Every mode does have a row, with its own anchor, on its family’s page.