Guitar interval understanding.

mwd

mwd

Power User
Many times, when playing pentatonic type scale in A I will bounce from an E note on second string to a D# note on third string then continue in pentatonic mode.

In calculating that interval I feel like the E would be my root or 1st note and the D# the 2nd note based on the way I'm playing it. One site that has a type of relationship calculator says if I calculate it as E to D# it's a major 7th but D# to E would be a minor 2nd.

I don't have enough interval knowledge to know if this is a calculator error or if that is fact based on the direction of travel of the root to 2nd note.
 

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The names of the notes are the same, but the intervals are different because of the distance between the notes. In a major 7th interval, one of the notes is 1/2 step below an octave away from the other. The major/minor interval naming is just a convention to distinguish between which interval is larger i.e. major 7th is the larger of the two intervals called 7ths, same for major/minor 2nd, 3rd, and 6th.

In a minor 2nd interval, one of the notes is 1/2 step away from the other note, i.e. D# to E or E to D#.
 
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Those are inversions. You're basically moving the second note an octave up or down in the opposite direction, which makes the interval much larger.

minor 2nd (between C4 and C#4) inverts to Major 7th (between C4 and C#3). It helps to view it on the piano to visualize the distance since the notes are all in a row.

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If you Google "Interval Inversions", you'll find a bunch of charts showing all the inversions.
 
The interval between the notes D# and E is a minor 2nd. The interval of E to D# (E - F# - G# - A - B - C# - D# - E) is a major 7th and is the interval within the key of E. This is usually called a scale degree. If the notes are adjacent, the note E would be the octave and the scale degree for D# is still a major 7th.

While the physical interval may be a minor 2nd when moving backwards on the guitar, the context needs to be defined. Both are "correct" depending upon the context; simple interval or scale degree.
 
JoKeR III said:
The interval between the notes D# and E is a minor 2nd. The interval of E to D# (E - F# - G# - A - B - C# - D# - E) is a major 7th and is the interval within the key of E. This is usually called a scale degree. If the notes are adjacent, the note E would be the octave and the scale degree for D# is still a major 7th.

While the physical interval may be a minor 2nd when moving backwards on the guitar, the context needs to be defined. Both are "correct" depending upon the context; simple interval or scale degree.
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This is correct if playing in the key of E. If I understand the OP correctly he is asking about playing a major pentatonic scale in the key of A and then adding in an occasional D#. In this case the scale degree of the E note is 5 and the scale degree of the D# note is 4.
 
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In the key of E
E—>D#=7th scale degree from tonic
D#—>E in key of D# is a minor 2nd
However if you shift the E up an octave then you’ll have a 9th in respect to the D# in the key of D#

At the end of the day, whatever is being played should be in respect to the key it’s being played.
Because you can also visit the D# key by using the locrian mode over an E for fun!
 
Yes, pentatonic in key of A but for identification if I play the notes on 5th and 4th fret on the second string alone I get same notes which I'm feeling is a semitone apart aka minor 2nd as some have mentioned. I think I'm letting the string change throw me.
 
mwd said:
Yes, pentatonic in key of A but for identification if I play the notes on 5th and 4th fret on the second string alone I get same notes which I'm feeling is a semitone apart aka minor 2nd as some have mentioned. I think I'm letting the string change throw me.
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The scale you’re using is irrelevant because the two notes in relation to each other are in a different key from A pentatonic minor. Intervalically, the D# in question is the same as the D# a half step below your E on 5th fret 2nd string.
The note is enharmonically equivalent to a fourth inversion of a E 7th maj or a D# with minor 2nd sounds dissonant !
 
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The interval between those two notes is a minor 2nd or "semi-tone" but in the context of the key of A, the note you are emphasizing in your video is the flat 5th, or "blue note". Commonly written as "b5". E is the 5th. Minor pentatonic is built with the Root, b3, 4, 5, b7. Add the b5 and you have the blues scale. You'll find the same note an octave lower on 6th fret on the A string in that position.
 
mwd said:
In calculating that interval I feel like the E would be my root or 1st note and the D# the 2nd note based on the way I'm playing it. One site that has a type of relationship calculator says if I calculate it as E to D# it's a major 7th but D# to E would be a minor 2nd.
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The interval of D# to E is a minor 2nd and E up to D# (as in an Emaj7 chord) is a larger interval, the major 7th but... you're playing in the key of A so relate the notes to the key... E would be the 5th, D# would be the flat 5. The distance between those 2 notes is a minor 2nd no matter if you're moving from E to D# or D# to E.
 
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