What Is an Interval?

Very important for chord and scale construction. If you pay attention you can learn and understand this in at least 1 week.

Ultimate Guitar
What is an interval? An interval is the space between one note to another. It can be a space of 2 notes in a melody (notes played one by one) or harmony (notes played simultaneously for example chords). Now let's take a look at this so called intervals. We have the first, second, third, fourth, fifth, sixth, seventh and octave. You could also include the ninth, tenth, eleventh, etc... but these will be explained later on. Note: I will now refer to the intervals in numbers. Since we know the names of the intervals, we now have to know that there are certain differences in them. We have 3 different type of intervals. Perfect, Consonant and Dissonant.
  • Perfect intervals are the 1, 4, 5 and 8(octave).
  • Consonant intervals are the 3 and 6.
  • Dissonant intervals are the 2 and 7. Now we need to look at some definitions for these intervals. Consonant and dissonant intervals can be minor or major, for example; m2, M2, m3, M3, etc. Perfect intervals are, as the name already says, perfect. They have no minor nor major. You can still diminish and augment this intervals. This can be very confusing but bare with me. If we see all the different interval names that a second has, from lowest to highest interval, it would look like this; dim2, m2, M2, aug2. This also goes with all the other intervals that are not perfect. Perfect intervals would be for example; dim1, P1, aug1. This as said goes for all the perfect intervals. Here is the complete chart of the intervals between the 1 (first) and the 8 (octave).
  • first: dim1, P1, aug1.
  • second: dim2, m2, M2, aug2.
  • third: dim3, m3, M3, aug3.
  • fourth: dim4, P4, aug4.
  • fifth: dim5, P5, aug5.
  • sixth: dim6, m6, M6, aug6.
  • seventh: dim7, m7, M7, aug7.
  • octave: dim8, P8, aug8. Let's do the same with with notes beginning with C, for a better explanation. Note: b means flat, # means sharp.
  • first: Cb, C, C#.
  • second: Dbb, Db, D, D#, D##.
  • third: Ebb, Eb, E, E#, E##.
  • fourth: Fb, F, F#.
  • fifth: Gb, G, G#.
  • sixth: Abb, Ab, A, A#, A##.
  • seventh: Bbb, Bb, B, B#, B##.
  • octave: Cb, C, C#. Now, there is something we need to know. It is called enharmonic equivalent. If you look closely and think it threw, you might notice something. C# and Db are the same notes. This also happens with other notes. This is called enharmonic equivalent. This is very important to know when building scales and chords. You can never use the same note twice in a scale. For example if the second is a F# you are not allowed to say that it is a Gb, because the Gb would be a diminished third and would have nothing to do with the second. This might be really confusing but it is important to know or else you can get in some real trouble when composing or writing scales and chords. I hope this lesson was understandable. If there are any questions, please send me a message.
  • 20 comments sorted by best / new / date

      It looks like your examples of consonant and dissonant intervals are inconsistent. In the first chart, you give four examples. In the second chart, you give five.
      I just now noticed what you mean. I'm really sorry about this mistake. I hope this doesn't happen again. I will redo this lesson in the future. I always check my lessons a lot of times before uploading them, but this time I made a huge mistake. Sorry for the inconvenience. Cheers
      Well it doesn't really matter if I give 4, 5 or 10 examples. In my opinion the count of examples are irrelevant. The important thing is to make it clear. cheers
      Thanks, man, very good lesson. Here in Brazil (in this month) the Guitar Player magazine did a lesson about this too, but it is always good to read more about.
      Brigado meu amigo. Nao se escribir ben en portugues mais eu acho que ta bom . Thanks for liking this lesson. Hope you stick to my next lessons
      You could have talked about semitones and whole tones. And you could also have said that there's a semitone between E-F and B-C and between every other natural note there's a whole tone. I would have started by just explaining major, minor and perfect intervals and later talked about diminished and augmented. And I would have written the intervals in order (both sharps and flats). What I mean is sharps: 1, #1, 2, #2, 3, 4, #4, 5, #5, 6, #6, 7 (#3=4, #7=1) and flats: 1, b2, 2, b3, 3, 4, b5, 5, b6, 6, b7, 7 (3=b4, 7=b1). The first one is chromatic scale with sharps and the second is chromatic scale with flats. You don't really need double sharp intervals anywhere - I don't even know if they have a name. (Are they called double augmented or what?)
      Double sharps and double flats are rare and only exist in a harmonic context. For all intents and purposes they are equivalent to the note a whole tone above the named note, especially on guitar where the use of equal temperament means we tend to think of each note as having a single name. As you probably already know, in a scale we try to ensure each letter is used to name only one note. For this reason, in the F-sharp major or harmonic minor scales we call the major 7th E-sharp rather than F because there is already an F in the scale. This convention is why double sharps exist. Keys using double sharps or flats are referred to as theoretical keys because there's no real reason for them to exist. An example is the G-sharp major scale in which the 7th, a G, must be referred to as F-double sharp because G is already used in the scale. This usually also means most, if not all other notes in the scale must be sharpened or flattened too. Thankfully, there's no real need for theoretical keys, because non-theoretical equivalents exist. In the case of G-sharp major this is A-flat major, which contains all the same notes but does not necessitate any double sharps. So while double sharps do occur they're effectively unnecessary. The one other context in which they may be seen is as accidentals in keys where a gap of two whole tones or more occurs between notes, however as far as I know no such key is used in western music.
      Very nice to see someone giving a good explanation about that. I unfortunately couldn't make that good of an explanation. Thanks very much. Cheers. PS: I do understand the theory though
      I get what you are saying. I could have done this lesson much simpler, but at the same time I'm not a teacher. I study music but I am still not finished with pedagogy, so there might be some misunderstandings. To answer your question about double flat and double diminished, I can only say that there are certain instances where these things appear. I Have never seen it myself but in music theory books you can find this examples a lot. I would suggest you to look it up if you don't really understand what I mean. Thanks for the feedback, it helps me out a lot to know, so my next lessons get better. Cheers.
      End of the first line of the last paragraph is a spelling error with "threw". Not trying to be one of those guys but I'd want to know if it was me! Excellent advice there, taught me a lot. Thanks!
      Yes, I probably wrote that wrong hahaha. I actually appreciate when I get corrected or else I won't learn . Glad you enjoyed the lesson. Hope you keep up for future lessons. Cheers
      In my opinion dim2, m2, M2, aug2 would be Dbb, Db, D, D#, which seems obvious and makes perfect sense to me. But why do you add another D## at the end? You did the same with thirds sixths and sevenths.
      I see what I did wrong here. I red my lesson a lot of times before posting it and just now I realized my mistake. You are completely right my good man. I'm really sorry for this mistake and I shall redo this lesson in the future without any. Thanks for your feedback. Cheers.
      so the interval is based upon the c interval where two steps on the firs two notes half step and two steps on the last 3 notes then a half step and octave? in other words on the staff of the sheet music with no flats or sharps in the signature is "C" and its assumed that its the 8 step octave sorry about the noob question...