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The Theory Thread

  • #2
    Moderators, Music Moderators Posts: 23,288 mod feylya

    I'd like everyone to post their little bits of theory knowledge in here. Hopefully we can make this into a good resource.

    I'll start by posting a handy post by conallgotspiked from the GigSmart forum about the Circle Of Fifths
    ok folks.... time for a music theory post instead of a musical equipment post.

    I recently remembered being taught about the 'Circle of Fifths' which is a simple mathematical graph which maps out key signatures and how they relate to each other. it also explains why there are sharps and flats, rather than just sharps (ie, C# and Db are the same note, but depending on the key signature they will have a different name)

    first off. lets start with the note C. the fifth of C is G (ie, the fifth note in the major scale, the commonly used 'power chord' is a first and fifth together)

    the fifth of G is D... and so on until you get a circle like this one.


    now. the key of C has no sharps or flats (the black notes on a piano keyboard)

    the key of G has one, the key of D has two, A has 3 Ehas 4...

    if you go anti-clockwias you'll see that F has one flat, Bb has 2...etc.

    like this...


    it also works for relative minor keys. eg the relative minor of C is Am which has no sharps or flats. the fifth of A is E and, lo and behold, the Key of Em has one sharp. it works in the exact same way around the circle.


    kinda cool huh?



  • #2

    Heres how I remember it
    (Ann Eating Bad Food Can Give Diaria All Evening)
    <b #>
    Ab Eb Bb F C G D A E
    The flats start a B and contines so 1b is Bb 2b= Bb + Eb and so on
    The sharps start at F and continue in the oppisit direction.

    This is only for 4 sharp and 4 flats as they are the only keys asked on the LC music sylibus. This can be extended to include all twelve keys (Gb,Db,Ab,Eb,Bb,F,C,G,D,A,E,B,F#,C# {note that F#=Gb and C#=Db} )
    1 2 3
    For the relitive minor count forward 3 (Cmaj G D Am) and use the scale from the major key but start on the 6th note to make it minor.
    If your a confused guitarist play the scales on a Keyboard and it will make more sence.
    Now whos up for some chord theory?

  • #2

    The BEST system for writing/recognising Scales and Key Signatures

    FLAT - b e A d g C f
    SHARP - f C g d A e b

    Major - Read from C to the right. When it goes behind C add a sharp or flat to the name as appropriate.
    Minor - Read from A to the right. When it goes behind A add a sharp or flat to the name as appropriate.


    e.g. What Major key has 5 flats?
    FLAT - b e A d g C f

    Start from C (For Major) and read right
    F has one flat, B has two, E has three, A has four, D has five.

    Is the note behind our starting note (C)? Yes it is, therefore the key is Dflat Major.

    e.g. What Minor key has two sharps?
    SHARP - f C g d A e b

    Start from A (For Minor) and read right
    E has one sharp, B has two sharps

    Is the note behind our starting note (A)? No it isn't, therefore the key is simply B Minor.

    This is the best system I've ever found for recognising and writing out key signatures/scales. If you have any questions just ask.

  • #2

    What is the symbol for writing a double flat or is there such a thing?

    Double flat is just two flats next to one another.
    Double sharp is a sort of X.

  • #2

    I have a question... can anyone tell me how to play C# minor (second inversion)
    on the guitar... some sort of diagram or something... I was working on a little piece on a piano and wanted transcribe it to guitar as an experiment.... etc.. or even just that chord.... how do you (or can you) invert chords on a guitar?

    I'm not a guitarist really but I'm just curious.. because I don't really know how chords work on the guitar e.g. bar chords... as opposed to the basic triad on a piano... Are they the same? anyone care to enlighten me?

  • #2

    www.chordfind.com should sort you out with figuring out the C# chord. I'm hopeless at theory, so I'll say no more.

  • #2


    where x is not played and the first 4 on the bottom is played on the 4th fret on the deepest string (the E string). The tab is viewed as you view the fretboard from above.

    Or up an octave

    Or combine the two if you have a Jimi Hendrix thumb.

    Guitar chords work in the same way as piano chords it's just that finding/getting them requires a bit more thought and memory. Where the piano has one long line of notes, the guitar has a matrix due to size constraints. The only way to get the chord you want is by understanding what note is on what fret and concluding the chord from that knowledge.

    Usually a guitar is tuned thusly:
    (as you look at the fretboard from above)

    Therefore the 3rd string (A) will play A when open. If one plays the 2nd fret on the 3rd string one will achieve the note B due to the fact that each fret is one semitone. And if one plays:

    .. they will be playing a CMajor chord.
    is C#Major


    This is another version of C#minor, the bass note being the minor 3rd.

  • #2

    One quick q, one thing i was thinkin the other day which i forgot how to do... was the minor scale...

    we all know the major scale - i.e. 1 4 5 are major and the other minors etc....

    but doesnt the minor scale come from the relevent minor of the major scale??

    so C major...

    I ii iii IV V vi vii

    Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdim,


    i ii III iv v vi vii

    Amin, Bdim, C#maj, Dmin, Emin, F#maj, G#maj...

    thats how u do it right, ( now i typed it out it looks wrong!) but its somethin i jus forgot how to do.....

    i think i confused myself writing that.... maybe im gone nuts

    It isnt jus the same as the relevent minor rite??

    So C maj

    I ii iii IV V vi vii
    C D E F G A B


    i ii iii IV V vii v
    A B C D E F G

  • #2

    the key siganture of the minor is the same as the relevant major, but when you're playing a minor scale, say, A minor, which has no sharps or flats like Cmajor, you raise the seventh note by a semitone to even out the scale... this creates a harmonic minor.. there's another type called a melodic minor but you don't really need to know about that... when playing the raised seventh you get almost a weird, eerie kind of melody..

    so, say you're playing the scale of A minor, it would be:

    A - B - C - D - E - F - G# - A
    1 - 2 - 3 - 4 - 5 - 6 - 7 (raised by a semitone) - 8

    with C major, with no sharps or flats, the scale just plays normally 1 - 8, as there is no need to even out the scale.

    if you see a piece of music with no sharps or flats, if it has lot's of accidentals (i.e. sharp or flat notes contradicting the key siganture), and these accidentals are mostly G#.. it's most likely gonna be in A minor....
    (i.e. most of the g's in A minor will be G#)

    so the key signature is the same with the relative major and minor.. but the minor will always have a raised seventh that doesn't show up in the key signature..

    Hope that helped and didn't confuse the hell out of you...

  • #2

    nah didnt confuse me! i know all of that about the harmonic and melodic minor and key sigs... but i was just thinkin yesterday about the minor scale and cudnt remember how it went at all!

    what chords are major and minor chords in the minor scale? as aposed to major thats the part i couldnt remember

    So in a major scale The 1st 4th and 5th are major chords and 2, 3 and 6 are minor and 7th is diminised...

    In a key signature starting with a minor... what notes are major/minor chords?

    Or Do u just write it in the Major key and just Use the minors from that,

    So if u wrote somethin in the the key of Aminor, it would actually be the key of C since Amin is the relevent minor....

    That right???

    In the Key of Amin... i remember writing music notation in majoy key signatures, and i forget what happens when writing with a minor Key signature....

  • #2

    well, if you wrote something in A minor, it wouldn't be the same as C major.. it has the same key signature on paper, but it's not the same.. in fact very different..

    i'd imagine that in a minor scale, the chords would be

    1, 4 and 6 would be minor

    3 would be augmented (remember the raised seventh)

    5 would be major

    2 and 7 would be diminished

    this is what it would seem to be in my view... I could be very wrong though.. I don't think in terms of which numbered chords are in a scale, I was really thinking of individual notes..

    If anyone can correct me please do...

  • #2

    I Think that in a minor key, the chord of 6 is major, such as in A minor, the VI chord is F major.

  • #2

    modular wrote:
    I Think that in a minor key, the chord of 6 is major, such as in A minor, the VI chord is F major.

    I think you're thinking of A natural minor (A, B, C, D, E, F, G, A) which would in itself the VI or the Aeolian mode of C major. So you wouldn't refer to F major as the VI of A minor, but as the IV of C major. Know what I mean?

  • #2

    can't say that I do... kind of... but not really.. but I was wrong about 6 being minor.. it is in fact major as modular pointed out... I think...

  • #2

    The VI should be minor...

    In major scales, the VI would be the Aeolian mode, which is minor.
    It's like this: C Major is C, D, E, F, G, A, B, C.
    Now, take that from the sixth note, which would be A.
    That scale would run A, B, C, D, E, F, G, A. This is the Aeolian mode (the natural minor), which differs from the major scale by having a minor third, a flat sixth and a minor seventh.

    Now, what you're doing is taking the the VI degree from that, which would be F. I can see how you think it would be major. The notes are there - F, A, C. But those notes aren't coming from A Minor, they're coming from C Major, where all of this confusing stuff started. F is the fourth of C, which is major. Damn it - if Fusion was here, he could explain this way better than I could.

  • #2

    Sauron wrote:
    well, if you wrote something in A minor, it wouldn't be the same as C major.. it has the same key signature on paper, but it's not the same.. in fact very different..

    i'd imagine that in a minor scale, the chords would be

    1, 4 and 6 would be minor

    3 would be augmented (remember the raised seventh)

    5 would be major

    2 and 7 would be diminished

    this is what it would seem to be in my view... I could be very wrong though.. I don't think in terms of which numbered chords are in a scale, I was really thinking of individual notes..

    If anyone can correct me please do...

    Thats kidna what i was trying to get at, i jus cudnt remember, now im jus kinda mroe confused! >.<

  • #2

    I think you're thinking of A natural minor (A, B, C, D, E, F, G, A) which would in itself the VI or the Aeolian mode of C major. So you wouldn't refer to F major as the VI of A minor, but as the IV of C major. Know what I mean?

    The minor key, I believe, usually has the sharpened 7th - that's why you see so many more accidentals in minor scores.

    So the scale of A minor (not natural minor) is:

    ... A B C D E F G# A B C D ...

    So taking that F and stepping up in the thirds would get you F, A and C.

    So where am I going wrong here?

    [EDIT] Really what I'm trying to get at here is that in the key of A minor, there can't be F minor, because there's no A Flat.[/EDIT]

  • #2

    What are you on about?

    Regarding chords relavent to the key of Aminor, they go as follows.

    If you are talking modally:

    Cmaj7 - Ionian

    Dmin7 - Dorian

    Esusb9 - Phrygian or just Eminor

    Fmaj7#4 - Lydian - or just Fmaj

    G7 - Myxolydian - or Gmajor

    Aminn7b6 - Aeolian - or Amin

    Bmin7b5 - Lochrian - or Bmin

    You can have variations on these chords(meaning alterations b5, b9 #5, #9 etc) but, if you change the 3rd from maj to min you are then modulating into a different key.


  • #2

    Thanks, Fusion, for clearing all that up.

    ...I was right.

  • #2

    Any chance this thread can be cleared up a little? There's a lot of speculation and guess work, a noob may not be able to differenciate between that and the facts.

    Such as.....
    Gordon wrote:
    Usually a guitar is tuned thusly:



    (as you look at the fretboard from above)

    Therefore the 3rd string (A) will play A when open. If one plays the 2nd fret on the 3rd string one will achieve the note B due to the fact that each fret is one semitone.

    this confused the fúck out of me when i first read it, i thought i'd been playing guitar wrong all these years :D

    Corrected VVV
    Gordon wrote:
    Usually a guitar is tuned thusly:

    1 - E
    2 - B
    3 - G
    4 - D
    5 - A
    6 - E

    (as you look at the fretboard from above)

    Therefore the 5th string (A) will play A when open. If one plays the 2nd fret on the 5th string one will achieve the note B due to the fact that each fret is one semitone.

    Does anyone have anything to add? this thread could be great but it's a ghost town at the minute.. I think i'll add something but i can't at the minute as i'm working.

  • #2


    I agree.. this thread could be a very useful tool but hasn't been updated for a while..

    tbh, I didn't really understand Fusion's explanation of the minor key.. but then again I am not as experienced with theory... eg I don't know anything about modes etc...

    as for how it could be cleared up, I don't know how it could be done other than deleting posts etc.

  • #2

    Right, mind if i add me tuppenceworth about scales and that?


    Startin off with C major: C D E F G A B C

    To get a mode of the major scale, use the EXACT same notes, just shift the startin point:

    So all the modes of C major are:

    C Ionian (Cmajor): C D E F G A B C

    D Dorian: D E F G A B C D

    E Phrygian: E F G A B C D E

    F Lydian: F G A B C D E F

    G Mixolydian: G A B C D E F G

    A Aeolian(A natural minor): A B C D E F G A

    B Locrian: B C D E F G A B

    Now minor scales:
    So weve started with C major, and got the relative minor (A natural minor, also called A Aeolian) by taking the 6th note of the C major scale, while still using the original notes of the C major scale.

    We now have A natural minor, with the notes A B C D E F G A
    The chords thereof being EXACTLY the same as the chords of C major, except startin on A minor.

    So the chords of the scale of A natural minor are:
    A minor, B diminished, C major, D minor, E minor, F major, G major

    And heres where we branch off for a moment


    Right we all know, tho we may not be consciously aware of it, that the chord change of 5-1 in the major scale is there or thereabouts THE most satisfying end to a piece of Western music (read:rock, blues, country etc etc) For this reason, its called a PERFECT CADENCE (a cadence bein the end of a musical section, theme or entire piece).
    Play some progression, lets say |C|Am|F G|C|

    Sounds end-y doesnt it?

    Even more end-y is if ya swap the G in that progression for G7.
    God knows how many songs have that, or somethin very similar at the end, and theres a THEORETICAL reason for it, aside from the fact that it just sounds finished.

    The reason is that some notes of the chord change G-C are a semitone, or a tone apart, which gives them a sense of wanting to move either up or down that "gap". This effect of wanting to "lean" back to the tonic (in this case the chord of C major) makes our ears expect the next chord to be that tonic, C major. When it turns out to actually be C major, we're satified, content and fulfilled and are happy to just leave it at that. Hence: its a good ending.

    To demonstrate these "leans" lets take the notes of the two chords and rearrange them a little:

    Gmajor: Cmajor:

    > G
    > E
    > C
    > C

    So in actuality, we have TWO "leans": The D sounds like it wants to go down to C, and it does. AND the B wants to move up a semitone to C and it also does.
    Also the fact that G stays at G give a fulfilling sound.
    To a lesser extent the D moves up to E, though from listening to it yourself, ya can tell that this is a less audible and/or important change.

    As for the G7-C cadence:

    G7 chord: C chord:
    > G
    > E
    > C
    > C

    So we have yet another "lean" from the F, which sounds like it wants to go to the E which it ends up doin.

    The gist of that whole tangent is that semitone distances from the chord of the tonic, and the bridging of these "distances" make for a satisfying cadence and/or end to a piece or section, more so than full tone distances.


    So after all that, back to minor scales.
    All of this theory grew mainly from so-called "classical" music, which was pretty much the only music there was until the 19th or 20th century.
    Nowadays monocles will not be dropped into brandy glasses if you and your band of rockers dont end a song on 5-1 (heart shaped box is a great example and notice the way it doesnt sound very "complete" at the end?)
    However back in the day, people sough intervals and cadences that let them know the piece was finished.

    To this end lets look at the Perfect Cadence of the minor scale:

    In our A natural minor scale (remember, A B C D E F G A?) itd be the chord of E G B to A C E, otherwise knows as Em to Am. As you will see, there is ONE, and ONLY ONE semitone gap between the two chords, i.e. B to C, and that is not at the tonic. To classical ears, this does not give a very satifactory final Cadence.
    Examining the notes, lets see what we can do about that:

    E - E: fine. Remember from the tangent above that G-G worked grand as an ending.

    B - C: fine aswell. Again in the G(7) to C above, the more semitones the better.

    So were left with G and A in our attempt to make this ending more of a "conclusion"
    We cant very well go near A can we? After all, our key is "A"minor, and messing with the A would wreak havoc.

    STOP THE PRESSES! Even a rudimentary knowledge of the blues will tell you that if we are playing a 12bar in C (using C, F and G majors), even tho in our scale of C major, the only major with a flattened 7th that fits with the key of C major is the chord of G major, we can still fairly legitimately throw the flattened 7th onto the C major, or F major chords without the sun blowing up.

    So it would appear that the seventh note of a scale is manoeuverable to a certain extent.

    "Ah-ha!" i hear you say, "while trying to make our Em to Am sound more complete, we were left with A and G, and G is the 7th note of the A natural minor scale!"
    Well done, but what can we now do to make it sound more complete, i.e. to try and get a semiton gap between the two, without changing the A?
    We can of course make the G sharp. This does not alter our scale dramatically, but it does serve to give us a stronger end on 5-1, giving us two semitone gaps, B to C and now G# to A.

    So now our scale is A B C D E F G# A. But what do we call it? Cmaj/A#5? Am#7? NOPE!
    We call it the A harmonic minor scale. Remeber harmony is to do with chords and their relation to each other, and we've just changed the scale to make the harmony a bit better (at the end of the piece at least), so thats where the name comes from.

    So to summarise our progress so far:

    Modes = EXACT same scale (e.g.C major) but shift the starting point.

    Perfect cadence = 5-1 (e.g. G to C)

    From that we get A Natural minor (A B C D E F G A)

    Changing this slightly so that our chords (harmony) will work better we get the scale of A harmonic minor (A B C D E F G# A)

    et voila.

    Now we move on to another minor scale, which also has its root in the A natural minor scale, which is in turn the Aeolian (6th) mode of the scale of C major scale.

    Now i wont go into the details of the origin of this scale (cos i dont know it) but lets just say that another random classical guy though that both the Natural, and Harmonic minor scales werent the May West for writing a decent melody(tune) with. He decides he wants to have the benefit of the top half of the major scale, with the bottom half of the minor scale (mostly because the minor third, in our case C is there and we cant really go changin that.)
    So after thinkin about it, he decides to bung and F# and G# onto our Natural minor scale. This gives us the scale of A B C D E F# G# A. Notice that its all but the scale of A major(A B C# D E F# G# A), without the C sharp?

    Another thing he decides is that it might sound good, to have the top half of the NATURAL MINOR scale in there too. How about we use the F# and G# when were going UP the scale, and F natural and G natural when were coming DOWN? Sure why the hell not!

    This gives us a scale that real theorist might say "has a sharpened 6th and 7th degree when ascending, and follows the key signature when descending"

    Which means that, since A minor (of any description) has the same key signature as C major (no sharps or flats), out scale goes like this:

    Ascending: A B C D E F# G# A (notice the sharp 6th and 7th)
    Descending: A G F E D C B A (no sharps or flats)

    Since we altered the Natural minor for the benfit of harmony, and called it the Harmonic Minor, And because we're now altering the scale for the benefit of melody, why not call it the MELODIC MINOR? why not indeed.

    A great example of the Melodic Minor scale is in Bach's Bouree in E minor.
    Page played a bit of it durin the Heartbreaker solo (at 4:43) in How the West Was Won, Jetro Tull did a flutey version, and Malmsteen himself did it once or twice live.

    So well take it in A minor (for simplicity):
    Anyway, the first bit of the melody goes like this:

    G --2-4-5---4-2-1---2-4

    Which translates to: A B C B A G# A B E F# G# A G F E

    And if we take the last two 3 note runs of this: F# G# A and G F E

    Now the first one, F# G# A, if you listen to the record is a run from the F# below our tonic (A) up to the tonic: that is it is ASCENDING, and lo and behold what we have said about the Ascending melodic minor scale holds true: The 6th and 7th notes of A minor (F and G) are sharpened.

    And the second one: G F E. As per the record, this is a run down from G just below the tonic to E below the tonic. i.e. the scale is DESCENDING, and what we said above still holds true; that the DESCENDING version of the Melodic Minor scale stick to the key signature, in this case no flats and no sharps.

    As an aside, the most commonly used minor scale (in any given key) is definitely the Harmonic Minor.
    After that it would probably be the Melodic Minor (depending on style of music), and then least common is the Natural minor itself.

    So there we have it, about an hours worth of typing which can now be summerised into about three lines.

    Starting with key of C major. C D E F G A B C

    6th mode (Aeolian mode) = A natural minor: A B C D E F G A

    Sharpen the 7th note for HARMONIC MINOR: A B C D E F G# A

    Sharpen both the 6th and 7th notes for the ASCENDING version of the melodic minor: A B C D E F# G# A

    Stick with key signature for the DESCENDING version of the Melodic minor:
    A G F E D C B A

    Minor Scales!

  • #2

    very enlightening.. thanks for that coyle... just one small thing..Are those modes you mentioned applied to every component of every scale in the same way?

    if so I'm assuming they're just names for the sequence of intervals in the octave of that particular stage of the scale? or something like that...

  • #2

    Thanks man!

    dunno to be honest. I presume so. As in, i know that the Melodic Major (yes major!) is a mode of one of the minor scales (dont ask me which though.)

    So to answer your question, id say modes are defined as the exact same notes of any given scale, just starting from different places.

    (incidentally do ya know of some place in cabinteely thats puttin on Grease in the first week of october?)

  • #2

    I'm afraid I don't.. no... unless it's the community school... a bit off topic but meh...

  • #2

    I think it is there yeah.

    So do ya have any more theory related questions?

  • #2

    not at the present time no... thanks anyway

  • #2

    Hey, impressive post coyle.
    I'm stuck a bit with harmony, can anyone help me out? I play Bb Tenor sax with a Bb trumpet and an Eb Alto, so harmony renders me completely paralysed and confused. What notes should the alto and trumpet play for a pleasing harmony? Is it a third up/ down (minor/ major third?), or does it depend on the changes? Right now I've only transposed and it doesn't sound great.

  • #2

    It depends what harmony ya want tbh. If ya can relate it back to C, then ya can do what ya want really.

    So when you play your C on the tenor sax ya get Bb, C on the trumpet ya get Bb and C on the Alto sax ya get Eb.

    So if ya all play the same not ya get Bb Bb Eb which would be pleasing enough, as its a perfect fourth.

    If the tenor and trumpet play their own C, and the alto plays his D,
    your gonna get a fifth, another perfect interval.

    Now if the tenor and trumpet play C and the alto plays his B, ya have a major third (concert Bb Bb D)

    If the alto plays Bb youll have a minor third (Bb Bb Db).

    So yeah it will of course depend on the key your in and all that, but if ya want them all to play the same note, have the trumpet and tenor play C (for example), and have the alto play the G below that, which both give ya concert Bb

    So if ya have the Bb pair play their own E note, the alto will have to play his B below that to sound the same.

    If this is any help:
    (sorry had to link cos it wouldnt space out properly)


    (btw concert basically means on a properly tuned piano. I.e. if ya tune a guitar to standard pitch, its a C or concert instrument. If ya tune it down a semitone its effectively a B instrument. i.e. when you play your C (third fret on the A string), whats comin out is actually a concert B note, if ya get me)

    If ya wanna get harmony goin, lets say your song goes A D Em D (Louie Louie by the way!), first work it out in concert pitch.

    So the chords are: song.jpg meaning we're in D major (if it was A, the E chord would be major)

    A=A C# E
    D=D F# A
    Em=E G B

    So the harmony you might wanna use is:


    in concert pitch of course.

    So, since the alto sax is pitched highest (i think?), lets give that the top line, the trumpet the middle line and the tenor sax the lowest line.

    Takin the alto sax on its own, we wanna have these concert pitch notes:
    E E E F# F# G G G F# F#
    comin out of the speakers.

    So to do that, look down the middle column of the diagram and find out which notes the alto sax needs to play, in order for Concert E F# and G to sound.

    Lookin at the diagram:

    To get Concert E, the alto would have to play C#/Db
    To get Concert F#, the alto would have to play D#/Eb
    To get concert G, the alto would have to play E

    Also, to find which key the alto wil be playing in, do the same again:
    Concert Key = D major
    Alto key = Bmajor (five sharps B C# D# E F# G# A# B) which works with the notes we've just got 6or7 lines above.

    Do the same now for the second line, the trumpet:
    Concert notes: C# C# C# D D E E E D D

    Concert key = Dmajor
    Trumpet key= E major (E F# G# A B C# D# E)

    So the notes that the trumpet should play to produce Concert C# D and E are (from the diagram): D# E F#

    And the same again for the tenor sax:
    Tenor sax key = E major (same as trumpet)

    Concert notes: A B

    Tenor Sax notes: B C#

    So now our 3 lines look like this (this one shows what each player should be playing on their own instrument by the way):


    So the sound that should come out now is somethin that resembles Louie Louie.

    So thats it for Lesson two kids :p , and ive another week of "studyin" left so any more questions ill try to help.

    btw Hope that "Bb, concert, Eb" diagram thing helps ya!

  • #2

    Right thought id say a little bit about Intervals in general.

    Lets start off by sayin that an interval is the gap or distance in pitch between two notes. It exists independantly of key signature etc etc, so an F# to Bb interval is an F# to Bb interval regardless of anything else.
    It is always measured from the lower note to the higher note.

    Interval descriptions contain two things:
    1. The number of the interval
    2. The quality of the interval

    An example is a "major third", "perfect fourth", "diminished 6th" etc.

    The "numbers" above are 3rd, 4th and 6th,
    and the "qualities" are major, perfect, diminished,

    As an example, lets take an easy one. We have two notes, lets say C and E. And we we want to determine the interval between the two of them.
    (In this case, we'll call the C the lower note)

    1. The number of the interval. The number of the interval is calculated by going back to the very basics of notes.
    Take the letters A B C D E F G and use these. Disregard completely any key signature, or accidentals or any of that and use the above list of notes to work out the number of the interval (Note: that is NOT the scale of A natural minor, its just a list of all the notes ever available for us to use within music)

    So to get the number of a particular interval, for some reason, they thought it was a good idea to include both notes when counting, so countin up from C to E we get 3 notes: C D E.

    Therefore, the interval from C to E is some class of a third.

    and indeed the interval from C quadruple sharp to E triple and a half flat is a third of some description.
    When trying to work out the number of the interval, disregard any note descriptions (flat, sharp etc) or key signatures, and just take the names of the notes, e.g. C and E, F and G etc.

    2. The quality of the interval. What kind of third it is depends....in order for us to determine what type of
    interval it is (or the interval quality), we have to think in terms of a major scale with the root being the lowest note (regardless of what key we are in at the moment)

    In this case, the root is C, so we build the major scale on top of that:
    C D E F G A B C

    we then work out whether or not our E note (remember?) fits into this or not. As you can see, it does, hence the C-E interval is called a Major 3rd

    If our E not was actually Eb, it would obvoiusly not fit into the major scale of the lowest note. Therefore, the interval of C-Eb is a Minor 3rd.

    This is only applicable for certain notes of the scale however.

    Below is a diagram about how semitone changes affect different intervals of a scale:


    In a major scale, the notes that have perfect intervals from the tonic are always always always going to be: Unison/Octave (ie. the tonic), the 4th and the 5th.

    The rest of the notes are obviously going to be Major intervals (i.e. 2nd, 3rd 6th and 7th notes.)

    With a fundamental knowledge of major scales, we can read these off fairly routinely; e.g. if someone asks us what the interval from C to G is, we can quickly see that G is the fifth note of the scale of C major, and is indeed in the scale of C major, therefore the interval itself is a Perfect 5th.

    The trouble arises when the higher note of the two is not found in the major scale of the lower note.

    Now for an example
    Lets take, for example, the notes C and Gb.
    This could be any scale, any mode etc. (That is to say that the intervals of notes exist outside of concerns about key signatures etc).

    And imagine that we are trying to work out the interval between the two.
    Also imagine that Gb is the lower of the two notes (for fun!)

    1. First of all lets get the Number of the interval:
    Disregarding accidentals etc, we have G and C.
    G A B C....which means that we're dealing with some class of a Fourth.

    2. Now let's build a major scale from Gb upwards:
    Gb Ab Bb Cb Db Eb F Gb

    and wonder to ourselves "does the C note fit neatly into that?"...and of course it doesnt. We now think in terms of "what kind of a C notes does actually fit into the major scale of Gb?" and it'd be Cb of course.

    So from the diagram above, the interval between Gb and Cb, both contained in the major scale of the lower (Gb) would be a perfect fourth.

    BUT!! We dont have a Cb. Rather we have a C natural. In effect we are increasing the interval by a semitone, and from the diagram, what do we get if our interval is one semitone bigger than would otherwise be the case with a perfect fouth? As you can see its an Augmented Fourth

    So to summarise:

    1. Intervals are the difference in pitch between two notes.
    2. They are measured from the lower note, to the higher note.
    3. They exist outside of any concerns about key signatures.
    4. They have both a number and a quality (e.g a 3rd that is major is called a major third)
    5. To get the number, simply take the two note letters D, F , B etc and count up from the lower to the higher (including both in your count)
    6. To get the quality, build a major scale on the lower notes, and see if the higher notes fits into this.
    A. If it does:
    i. and you have determined it is either an octave, 4th or 5th away from the lower notes, then its a Perfect interval.
    ii. if the higher note fits into the major scale, but is not either a octave, 4th or 5th, then it is a Major interval.
    B. if it doesn't:
    then you have to consider what quality the interval would have had, if the note was in the major scale (such as the Gb C example above), and whether the note you actually have has made the interval bigger or smaller.

    Consult the diagram thing above to figure out what effect making the interval bigger or smaller by a semitone has on your interval quality.

    7. String the number and quality together, e.g (major 6th) and youre laughin!

    Hope that helps, it was hard enough to explain, but its a start anyway!

  • #2

    Hey, just a bit about notes, and readin music and that (scanned from one of those blue manuscript book things!)



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