The interval between, say, C4 and D4 is a major 2nd.

What is the interval between B#3 and C4?

Is it still a 2nd?

For lack of a better term would it be something like a minor minor 2nd?

1 Answer 1


You have:

  • B# - C: Diminished 2nd (same as B-Cb)
  • B - C: Minor 2nd
  • B - C#: Major 2nd (same as Bb - C)
  • Bb -C#: Augmented 2nd

If I'm not mistaken, there are also double diminished and double augmented intervals, like Bb - Cx but rarely used

Generally the interval qualities are: Diminished, Minor, Major, Augmented or Diminished, Perfect, Augmented.

  • Worth mentioning that on a keyboard instrument, this is recognized as a unison, but there is a difference on other instruments such as string instruments (where a sharp is played differently as a flat, e.g. in F#-Gb diminished 2nd). Commented Feb 25, 2016 at 10:18
  • @PierreArlaud F#-Gb would be a unison both in a piano and a guitar. What is exactly your point? Commented Feb 25, 2016 at 10:20
  • 2
    @Shevliaskovic my understanding is that technically, F#-Gb is an enharmonic interval and both notes are separated by a comma. On a violin you would make a slight difference (Bb should not be played exactly the same as a A#), which is impossible on a piano. Commented Feb 25, 2016 at 10:39
  • I play double bass and I've never heard of this. I try to play A# and Bb the same. Otherwise how would a violin or double bass play with a piano? won't it sound out of tune in times like this? Commented Feb 25, 2016 at 10:41
  • 2
    @Shevliaskovic to avoid an extended discussion, I can thankfully redirect you to this answer music.stackexchange.com/a/11816. This would in theory be a problem if one violin played an A# and another one a Bb, but having both notes written at the same time on the sheet would seem very experimental to me. The point was: a diminished second is not exactly a unison as there is a very thin difference between a sharp and a flat or between a chromatic and a diatonic tone. Commented Feb 25, 2016 at 10:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.