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the IV and scale question

Discussion in 'General Instruction [BG]' started by gorskkr, Feb 4, 2013.

  1. gorskkr


    Jan 14, 2013
    I'm new to the bass and music theory in general although i have played guitar for the better part of my life. I have a question that has kind of stumped me...

    I've learned that the I, IV, and V chord are the most used chords in any key. However, I'm not sure why the major pentatonic removes the IV (4) from its scale. You would think the bassist would be playing root A whenever the A chord is being played by the guitarist

    example: the song "Lady Picture Show" by Stone Temple Pilots starts off with E, B, and A repeat for intro and verse. When creating my bass line I can't hit the root note of "A" bc its not in the E major pent scale. This seems off to me...

    You may say, "well just play the normal E major diatonic scale". I would agree with this, however, I've been told that the pent scales are really the go to scale when creating bass lines and soloing (guitar or bass).

    I do play guitar so perhaps I'm a little confused with the integration of the pent scale? Is the pent scale more for guitarist to improvise/play lead? Do I mostly use the diatonic scale when when playing a song like the one above?

    BOTTOM LINE: I just find it hard to believe that the pent scale is lauded as the "go-to" scale yet it removes the 4th which besides the Root and 5th is the most used chord progression. This has really been frustrating me lately!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Please give me some good insight so I don't go home and try to find the answer to this and it cuts into my precious bass playing time.
  2. ics1974


    Apr 13, 2012
    Because it takes away the different intervals that make up the modes
    let’s compare the modes to the pentatonic.

    Let's look at all the possible major scale modes for C using notes names and numbers.

    C D E F G A B - C Ionian (C is chord I in the key of C)
    1 2 3 4 5 6 7

    C D E F# G A B - C Lydian (C is chord IV in the key of G)
    1 2 3 #4 5 6 7

    C D E F G A Bb - C Mixolydian (C is chord V in the key of F)
    1 2 3 4 5 6 b7

    C D E G A - C major pentatonic
    1 2 3 5 6

    Notice the C major pentatonic has taken away the notes (numbers) that are different for each mode and only kept what is common to all.

    The same thing happens in minor keys, so let’s look at all the possible minor scale modes for A.

    A B C D E F# G - A Dorian (Am is chord ii in the key of G)
    1 2 b3 4 5 6 b7

    A Bb C D E F G - A Phrygian (Am is chord iii in the key of F)
    1 b2 b3 4 5 b6 b7

    A B C D E F G - A Aeolian (Am is chord vi in the key of C)
    1 2 b3 4 5 b6 b7

    A C D E G - A minor pentatonic
    1 b3 4 5 b7

    Again notice the A minor pentatonic has taken away the notes that are different from each mode and only kept what is common to all.

    The pentatonic scale is missing the intervals that complete the whole major scale. These same missing scale degrees are what make the modes different. Without them there is no conflict regardless of mode.

    As a bass player I would not use one pentatonic scale over all chords as it will have missing chord tones like you noticed.
    You could however switch pentatonic scales over each chord.
    E major pent over the E chord
    B major pent over the B chord
    A major pent over the A chord
    but make sure you are landing on chord tones when you should be.
  3. MalcolmAmos

    MalcolmAmos Supporting Member

    Notes - major scale will use the 2 and 4 note of the scale as passing notes, i.e. will not normally accent or land on them. They are used as passing notes only.

    Now chords, that's another story. The IV chord normally brings tension and interest and pulls the progression into the climax V7 chord. So the IV chord is as you say an important chord. In a chord progression the ii and the IV have the same function, i.e. they want to move to a dominant chord. So both the ii and IV CHORD do play an important role in our music.

    As we normally play the chord tones of the chord - there are not a lot of 2's and 4's in a chord's makeup.

    Chord tones of the Basic Chords
    • Major Triad = R-3-5
    • Minor Triad = R-b3-5
    • Diminished Chord = R-b3-b5

    Chord tones of the 7th Chords
    • Maj7 = R-3-5-7
    • Minor 7 = R-b3-5-b7
    • Dominant 7 = R-3-5-b7
    • ½ diminished = R-b3-b5-b7
    • Full diminished = R-b3-b5-bb7

    About the only chord that will have a 2 or 4 in it's makeup is the sus chord and how many of those do you run into?
  4. elgecko


    Apr 30, 2007
    Anasleim, CA
    There are no rules when creating bass lines. Theory explains music...music isn't written to conform to it.
  5. Snarf


    Jan 23, 2005
    New York, NY
    The root of the IV chord is an avoid note for the I chord. If you use it a lot, it can create an awkward sound and make the I chord sound as if it were an inversion, which shouldn't happen in this context.

    Feel free to use the major pentatonic scale starting on the root of the IV when you're actually on that chord, though.

    Also to everyone above: TMI.
  6. Febs

    Febs Supporting Member

    May 7, 2007
    Philadelphia, PA
    Don't play the E major pentatonic over the A chord. Play the A major pentatonic over the A chord.
  7. phmike


    Oct 25, 2006
    Nashville, TN
    You don't play the "E" pentatonic scale for the "A" chord - you would use notes from the "A" pentatonic scale for the "A" chord. (my preference would be chord tones from each chord but the correct pentatonic would work)

    (looks like 3 of us posted at about the same time)
  8. gorskkr


    Jan 14, 2013
    FYI - I've been using this to help teach myself bass and music theory:


    Here's essentially what I do based on the knowledge I've acquired from this site. I'll put on a drum backing track on my boss loop station pedal. I select a key (lets say G for this example). I'll then pick up my electric guitar and create a simple song/loop starting with G and then going to the V (D) then the IV (C) (I may reverse the order or throw in another complimentary chord). I'll then loop that and pick up my bass to practice going over the chord progressions and create simple lines to improve my bass playing.

    At first, I had no problems bc I first memorized the G Major Diatonic Scale (at this time I didn't even know what the pent scale was). So I'd play the major diatonic scale along with the song in G and it sounded good and I'd be sure to hit all the root notes when they came up. I thought I was getting the hang of creating music on my own. Then I started reading up on how to better my guitar improvising, and everywhere I read online kept saying "Learn the pent scale! everything sounds good in it and you avoid the notes you don't want to land on." So then I thought, well it looks like I shouldn't now be playing the C (IV) note in the chord progression above- what gives this doesn't make sense.

    So maybe I'm confusing two schools of thought? Like maybe the pent scale is more appropriate for guitar improvising and less so for bass where you MOST CERTAINLY always have to play the root of the chord that's being played by the guitarist?

    Sorry for the long rant and added info. I figured the added background and approach I take might help make more sense for you guys. I had a feeling I maybe wasn't articulating myself properly due to my lack of "fluency" in music theory.
  9. gorskkr


    Jan 14, 2013
    OH OK........I guess I was thinking if a song was in the key "G", I could only play a "G" scale for the whole song. From what the 3 of you (who posted at the same time) just shared with me, it looks like I just always play the root of the guitarist's chord progression and play the scale that corresponds.

    as "ics" said:
    "As a bass player I would not use one pentatonic scale over all chords as it will have missing chord tones like you noticed.
    You could however switch pentatonic scales over each chord.
    E major pent over the E chord
    B major pent over the B chord
    A major pent over the A chord
    ^^this is what I need to do then. I guess I was functioning under the wrong logic and thus confusing myself.
  10. phmike


    Oct 25, 2006
    Nashville, TN
    I think part of your problem is you may be confusing how chord progressions, scales and chord formulas are labeled. The "C (IV) note" you mention is a chord not a note. (I'm assuming you are thinking the "G" major pentatonic scale is R 2 3 5 6 and does not contain a 4 = "C")

    Usually (at least in my travels) chord progressions use Roman numerals (Example: I IV V vi, folks often (IMO they should) use upper case for major and lower case for minor). Scales and chord formulas use Arabic numbers (Example: major chord = R 3 5, major pentatonic scale = R 2 3 5 6).

    EDIT - Adding this to help show relationships.

    I IV V chord progression in the key of G = the G C D chords 
    I    ii   iii  IV   V    vi   vii° (I)
    G    A    B    C    D    E    F#   (G)
    Major scale notes 
    R    2    3    4    5    6    7    (8)
         9         11        13 
    G    A    B    C    D    E    F#   (G)
    C    D    E    F    G    A    B    (C)
    D    E    F#   G    A    B    C#   (D)
    Major Pentatonic Scale notes 
    R    2    3    .    5    6    .    (8)
    G    A    B    .    D    E    .    (G)
    C    D    E    .    G    A    .    (C)
    D    E    F#   .    A    B    .    (D)
    Major chord notes 
    R    .    3    .    5 
    G    .    B    .    D 
    C    .    E    .    G 
    D    .    F#   .    A 
  11. FretlessMainly


    Nov 17, 2010
    You are confusing scale degrees (notes) and chords here. The 4th scale degree is typically omitted from Major/Dominant chords or scales used over these chords because it can clash with the natural 3rd.
  12. Sni77


    Aug 23, 2012
    Vienna, Austria
    As many have pointed out, use the appropriate pentatonic for each chord. What I find very important is to know your triads and seventh chord arpeggios, I think you should practice those before practicing the pentatonics. Pentatonic scales can then expand on the chord tones to add tension and passing notes.
  13. MalcolmAmos

    MalcolmAmos Supporting Member

    Yes. Chord tones first. Scale notes can be used as fills and walking notes to the next chord change. Think chord tones first.


    The songwriter decided and then placed each chord in the appropriate spot to harmonize the melody notes that are being played. Harmonization happens when the melody line and the chord line share like notes - at the same time in the song. The songwriter has taken care of harmonization by placing this specific chord - with it's notes - here at this spot. Makes since we stick with the notes that are harmonizing, i.e. the chord tones, in our bass line.

    How many?

    If the rhythm guitar and keyboard are playing this chord, we have harmonization so our notes are more for rhythm than melody. Yep, give that some thought. Root on one...That's why roots work. Two like notes would be better, thus the root-five works great - root on one and five on three. If you need more; help yourself to the 3's and 7's - the rest of the chord tones on the second and forth beat. IMO that's enough. I take care of the rhythm and call attention to the chord changes. In my World the lead breaks are handled by the lead electric, pedal steel, vocalists and the keyboard. There instruments do a better job of lead breaks than mine so I let them handle this portion of the song. I've already got enough to take care of with keeping the beat and calling attention to the chord changes.

    That's how I prioritize what needs to be done.
  14. Bainbridge


    Oct 28, 2012
    I'd like to chime in with a piece of information that has not yet been mentioned. There are two "categories" of scales: harmonic and melodic. Harmonic scales are those which provide a pitch palette for harmonic sequences. The most familiar of these is the major scale.

    D major: D E F# G A B C#

    We can neutralize the note names with numbers to give us the pure structure of the scale: D E F# G A B C# becomes 1 2 3 4 5 6 7

    You might know that triads may be derived from a major scale by stacking diatonic thirds on every note of the scale.

    D Em F#m G A Bm C#° (I ii iii IV V vi vii°)

    From there, we can create some basic chord progressions, like IV V I, IV ii vii° V I, whatever. You'll notice that those numerals are not all the same letter case - some are upper case (I IV V), some are lowercase (ii iii vi), and one has a little doodad on the end (vii°). This is obviously connected to the qualities of the triads found in the harmonized scale (I IV V are major, ii iii vi are minor, vii° is diminished), but it gives us another bit of information: we're looking at major keys, so we are interested in 'majorness'. Where better to go for the major sound than the major triads? I IV V will give you the modal essence of the key. If you play I IV V all day long, it's going to sound happy and major and completely uniform. We call I, IV, and V "primary triads" for the reason that they provide the clearest picture of a key. In practice, when you start playing around with these primary triads, this is the order that we want to hear them in: IV V I.

    But, hey, what about those other triads? Since I IV V is the primary group, we are going to call ii, iii, vi, and vii° "secondary triads". The function of secondary triads is to substitute for the primary triads, and to give color to the progression. In this case, the secondary triads give a little 'sadness' or minor feel to what is otherwise a 'happy' or major pitch collection. Here is a list of the corresponding primary and secondary chords:

    Notice there's no iii. It's a bizarre triad that shares two notes in common with both I and V, so it is functionally unclear and is usually reserved for special occasions.

    This means that you can go back to our big mama progression, IV V I, and swap out one chord for another:

    ii V I
    IV vii° I
    IV V vi
    ii vii° I
    ii V vi
    IV vii° vi (vii° vi is rare)
    ii vii° vi
    And you can also put a couple of chords from the same functional grouping together next to each other. So, I & vi, IV & ii, V & vii°, then either I or vi at the end. Typically, you move from primary to secondary (except in the case of vii° to V, but I won't get into that right now), so the entire progression ends up looking like this:

    This is the framework for tonality, and I emphasize 'framework' because the diatonic chords give us the basic language to which we constantly refer back to. Take this progression:

    Bm D7 G B7 Em E7 A7 D

    If you try to find a scale that works smoothly over all of that, you're going to be a mess. Check out why:

    Bm: B D F#
    D7: D F# A C
    G: G B D
    Em: E G B
    E7: E G# B D
    A7: A C# E G
    D: D F# A
    If you order all of those notes and get rid of the repeated notes, this is what you're left with:

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

    There are nine notes in there. If you have a name for that scale, more power to you, but it's the completely incorrect way to go about it. Let's have another look at that progression and try to pick out the elements of D major.

    Bm: vi
    D7:  Something else, don't worry about it.
    G: IV
    Em: ii
    E7: Something else, don't worry about it.
    A7: V7
    D: I
    Okay, discounting the weird things that we can't explain yet, this is a pretty basic progression in D major: vi IV ii V7 I. See the framework? Even though we have some chords that are completely foreign to the key of D major, I am confident in saying that this progression firmly belongs to the key of D major and the D major scale, because there is a strong sense of functionality and moving toward the tonic triad, D. The two chords that we can't yet explain are called "secondary functions" (not to be confused with the secondary triads we looked at earlier). I won't get into all that right now, but here is how one analyzes such a progression:

    vi V7/IV IV ii V7/V V7 I

    A little beyond where you're at, but I think you can get what's going on.

    V7/IV > IV, V7/V > V


    That's harmony in a nutshell. I also promised you some exposition on melodic scales. As the name would suggest, melodic scales are principally used in the creation of melodies, and are not really known as a source of harmonic progressions (nor are they harmonically flexible). Melodic scales, or "modal" scales, predate their harmonic counterparts by eons. Famous examples include the major scale (I prefer "diatonic scale" when it is used modally, as that encompasses dorian, phrygian, lydian, mixolydian, aeolian, and locrian as well), the melodic minor scale (duh), all those exotic Middle-Easterny scales, and the 'pentatonic' scales.

    Remember, melody predates harmony by, like, forever. The reason? It's easier to put one note after another than it is to stack them on top of each other, because it's easier to build an instrument that plays one note after another than it is to make on that stacks notes on top of each other. Harmony is really complicated. How long did it take for me to explain the primary/secondary thing? That's just the tip of the iceberg, too. Consequently, when one looks at music from non-harmonic musical cultures, or at traditional music that might be played by a single person with a tinwhistle, there isn't as much interest in filling out harmonies, and the music itself is likely going to be harmonically simple (maybe one or two 'chords', historically a drone). Here are a couple of United States folk tunes that utilize an E major pentatonic scale:



    There are actually a couple of A's in Willow Garden, but that doesn't negate the pentatonic-ness of the tune; if you were looking at a 5x7" canvas that was completely covered in red paint, spare a miniscule drop of blue paint on the edge of the composition, I think you would understand when somebody asks "Did you see the red painting?". Besides, I think that Willow Garden picked up a couple of extra notes when it was imported from Scotland or Ireland or wherever - the original is purely pentatonic, as far as I remember. At any rate, this music is completely happy without chords. You can hum these melodies, and they sound cool and self-contained. Music that uses these modal scales, by necessity, is much more concerned with melodic motion than it is about harmonic construction.

    Of course, one can harmonize the melody with a harmonic system (in other words, add chords to it) - all you have to do is look at the melody, decide what chord progression the melody implies (For example, the last two notes of both of those songs, F# & E, represent the V7 [B D# F# A] and I chord [E G# B] respectively; alternatively, anytime there is a C#, you're probably going for vi or IV. Between those, you get D# and A - neither of which is in E major pentatonic.), and it's only a matter of sticking something underneath. But when you try to melodize a harmony ('melodize' isn't a real word for a reason), you're putting the cart before the horse. It can be done, but it's not a very good compositional model. By far, when I'm writing, I write the melody and all the while have a strong sense of harmonic progression while I am writing said melody.


    All in all, don't worry that the pentatonic scale doesn't represent the IV chord; it's not meant to. Harmony and melody are separate entities in this case. Learn chord tones (the bass is largely a harmonic role, after all), leave the melodic stuff to the melody writers. "Forest for the trees" and all that.
  15. Wasn’t the OP premise that he couldn’t play and A under the A chord because it wasn’t in the E pent scale?

    Play the A if its the root of the chord. Forget about scales.

    I didn’t even read the encyclopaedias everyone posted here

    Play the friggin root.
  16. Bainbridge


    Oct 28, 2012
    ^ +1
  17. gorskkr


    Jan 14, 2013
    @Bainbridge - Thanks for all you wrote down that's certainly an overwhelmingly amount of info for me to consider. I'll admit I don't understand a lot of it but I'm slowly picking up.

    It seems like I need to focus on integrating more triads into my bass playing. Along with incorporating the dominate 7th. Seems like R, 3, 5, b7 are really the best sounding given you're playing a major scale.

    My bass playing is coming along, but I think I need to get more into music theory as it applies to creating good chord progressions on my electric guitar. I guess I need to read more into music theory so I can create and understand the relationships to make an awesome riffs on the guitar that I can then play my bass on top of and add some drums (getting sick of my loop pedals drum presets, thinking about getting a drum machine, any suggestions are welcomed...)


    ^^not sure if this will post correctly but I made this song up last night.

    on guitar I play Dm, Am, G, D. I looped a Dm pent scale that I used for this bass line. The drum track is one of the presets that I tap-tempo'd to sync with my song. It's pretty basic but I literally just started playing guitar again after taking over 5 years off and bought my first bass about 3 weeks ago.
  18. Febs

    Febs Supporting Member

    May 7, 2007
    Philadelphia, PA
    You can never go wrong with chord tones as a starting point. Make sure you understand how to construct common chords. For example, here are the chord tones for five common chords (using C as a root for this example):

    C Major = Root, 3, 5 = C E G
    C Major 7 = Root, 3, 5, 7 = C E G B
    C minor = Root, b3, 5 = C Eb G
    C minor 7 = Root, b3, 5, b7 = C Eb G Bb
    C7 = Root, 3, 5, b7 = C E G Bb
  19. gorskkr


    Jan 14, 2013
    Thanks. and yes that is definitely where I'm at right now in my bass music theory journey. Although, isn't C7: R, 3, 5, b7?
  20. Febs

    Febs Supporting Member

    May 7, 2007
    Philadelphia, PA
    Good catch. I fixed my post.