Submajor and supraminor

This article is about the two interval qualities closer to neutral than major/minor. For the opposite, see Supermajor and subminor.

Submajor intervals are between standard major and neutral intervals, and likewise, supraminor intervals are between standard minor and neutral intervals. The prefix "supra-" is used in supraminor to avoid ambiguity with whether "superminor" would mean "sharper than minor" (i.e. supraminor) or "more extreme than minor" (i.e. subminor). For example, submajor thirds are found between about 361 and 375 cents, and supraminor thirds are found between about 327 and 341 cents.

Submajor and supraminor intervals are hard to find as just intervals (partially due to the range of supraminor sixths corresponding to acoustic phi), and do not correspond cleanly to any subgroup of JI. However, here are some examples of just submajor and supraminor intervals:

• 11/10 (165c), submajor second
• 17/14 (336c), supraminor third
• 21/17 (366c), submajor third
• 34/21 (834c), supraminor sixth
• 28/17 (864c), submajor sixth
• 20/11 (1035c), supraminor seventh

Submajor and supraminor intervals are found in flatly tuned diatonic scales, such as where the fifth is tuned to around 691 cents. For a given neutral interval k in cents, submajor ranges from roughly k+10 to k+24 cents, and supraminor ranges from roughly k-24 to k-10 cents. For example, submajor seconds are found between about 157 to 171 cents, containing the lower range of the "equable heptatonic" region defined by Margo Schulter.

In the theory of MidnightBlue, some of these ranges are considered "dead zones" as they introduce potentially unwanted ambiguities between interval categories. However, in other practices, this might be leveraged to musical effect.