Talk:Interval class

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source for formula definitions: Basic Atonal Theory by John Rahn.

Contents 1 Error 2 Oops! 3 Problems 4 Diatonic and chromatic

[edit] Error

"For example, the interval class between pitch classes 4 and 9 is 5 because 9 - 4 = 5 is smaller than 4 - 9 = -3 ≡ 7. See modular arithmetic for more on modulo 12."

IMHO, 4 - 9 = -3 ≡ 9 (modulo 12), because -3 + 12 = 9. At least I hope I understand the article correctly (I am not completely sure, that's why I will not edit the article). -- Viliam Bur 195.46.70.44 13:17, 3 February 2006 (UTC)

[edit] Oops!

Thank you for bringing that error to my attention! I'm not sure how I arrived at 4-9=-3, but the answer, of course, is 4-9=-5, which is equivalent in mod 12 to 7. Sorry about that. And yes, -3 does equal 9 in mod 12. Thanks again for noting that oversight. Psfitzgibbon 03:45, 4 February 2006 (UTC)

[edit] Problems

Contrary to what is said in this article, the notion of "interval class" can also defined in pitch space. (The interval class between C4 and E4 is 4, just as the interval class between E4 and C4 is 4.) Consequently, the contrast with tonality terminology is weak -- what is being contrasted here are pitch intervals in tonal theory with pitch class intervals in chromatic theory. Tymoczko 17:05, 23 February 2006 (UTC)

This article, as I see it, is not intended for people like you who already understand interval class -- it's for the uninitiated. Therefore, the point of the terminological comparisons is to give those who already understand basic tonal theory something to latch on to, as well as to illustrate the need for related but discrete post-tonal terminology.

Of course atonal terminology contains a correlate to tonal pitch interval: unordered pitch interval. But, as you know, interval class IS NOT the same thing as unordered pitch interval -- the former is defined only in pitch class space; the latter, only in pitch space.

Thank you for writing, though. If you wish to do so, I certainly encourage you to contribute again.

Best, Psfitzgibbon 00:25, 14 May 2006 (UTC)

[edit] Diatonic and chromatic

The article uses the terms "diatonic" and "chromatic" without adequate explanation. These terms are the cause of serious uncertainties at several Wikipedia articles, and in the broader literature. Specifically here, diatonic is not necessarily an adequate gloss on heptatonic, especially given the way things are classified at the article Heptatonic (to which I have just provided a link). And even if diatonic is intended at the present article, that excludes other heptatonic scales from treatment here. But that can't be right! Some of us thought that both terms needed special coverage, so we started up a new article: Diatonic and chromatic. Why not have a look, and join the discussion? Be ready to have comfortable assumptions challenged! – Noetica^♬♩ Talk 06:12, 6 April 2007 (UTC)