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How does one figure out scales from a Baseline? Say for example, the Rhythm Guitar plays Bm chord for 4 Bars and then Amaj for 2 and Gmaj for 1 and then back to Bmin. How do i figure out, what scale this is in so that i can play a solo containing the notes in a scale that fits to these chords.

My approach is trial and Error, i try and play a solo and record it and see if it fits and if i feel its wrong, i try out a different scale. What would be the most efficient approach in this scenario?

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    Trial and error was always a good way for many musicians and composers. The short cut is to study the theory they have developed of their practice. Dec 29 '20 at 20:46
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There‘s no most efficient approach but there are some good advices.

  • study the basics of chords and chord progression
  • listen to hundreds and thousands of songs
  • play from chords and chord tabs hundreds of songs

If you knew the basics of harmony and chord progression or you knew some more songs you would identify this Bm-A-G as the same as Am–G-F and as the progression i-VII-VI (which often is followed by V and as far as I knew the most popular progression beside the blues schema - almost all of my school bands earlier or later came on its track!)

Now this not at all a blues scale. But it is easy to improvise when starting at the fifth and playing around this tone, bending it, then a whole tone down and a minor 3rd up (in your case F#, E and A.

Listen e.g. to Gethsemane from Jesus Christ Superstar and look up in wiki for songs i-VII–VI

Added:

To extend the repertory of tones you can play with the pentatonic scale B,D,E,F#,A, ignoring the other chords.

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    I'm inclined to think that the most efficient approach is to play the piano. On the piano keyboard, the possible scales just appear in front of my eyes. Nice linear representation where each pitch is only in one place. Even when playing guitar, when in doubt, I just "look" at a piano keyboard in my mind. The guitar fretboard has everything all messed up and obfuscated. Dec 29 '20 at 20:36
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    I fully agree with you. The keyboard is the best way to understand the harmony and all theory because its keys (the shape of black and white keys) represents the system of the tones. I always said: I‘m not teaching keyboard playing, I‘m teaching music and music theory by keyboards. Dec 29 '20 at 20:42
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    I do a little bit of occasional teaching as well, and I must say, the piano keyboard just has to be introduced even for guitarists. "Here's a tactical map of what's happening with all the notes " It's instrumental .... :D The only other possibility is musical staff notation, but it's far more difficult as a visual platform, because it cannot be played, and because it's hiding things with the sharps and flats etc. But the piano shows all the notes at the same time. Dec 29 '20 at 20:58
  • @piiperiReinstateMonica Piano keys are linear, but i am not sure its that simple to figure out what note a key(Black/White) is without looking at the reference C Note or? Guitar fretboard is confusing, With the right technique and a lot of practice it is possible to figure out keys on fretboard.
    – Abel Tom
    Dec 30 '20 at 17:49
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Be aware that there isn't always one scale that fits a sequence of chords. However, a good start point for you, rather than a totally random approach, would be to consider the chords involved. Here, Bm, A maj. and G maj. That, at least, narrows it down to three scales. Since it starts on Bm, that seems to be a good start point. In fact, the chords Bm, A and G all come from the Bm key.

Before anyone says anything - also be aware that minor keys have 'extra' notes, which often fit with the melody, thus meaning changes of chords. So here, the notes from Bm natural fit quite well. What often happens when people solo over a set of chords is that they subtly change a note or two to better fit certain chords. They might, for example, play notes from Bm scale over Bm, A scale notes over A, and - you've guessed it - G scale notes over G. Not all those notes belong in all the scales, but a vast majority do.

And, as always, solos benefit from 'outside' notes, adding a bit of spice. So, as all my students understand, any note, anywhere, in any piece, in any key, can - and will - fit, if you know what you're doing. So, don't religiously stick to the scale notes, slip in a couple of 'outside' notes occasionally. Your listeners will love it!

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  • I tried the B blues scale? And it sounded really good. Is that a major or minor pentatonic scale? Speaking of outside Notes . Notes in B Phrygian dominant scale did not seem to fit quite well.
    – Abel Tom
    Dec 29 '20 at 17:55
  • I avoided blues on purpose! There are two blues scales - major and minor, both of which work quite happily, given an approriate genre - so I guess you used B minor blues. Of course it'll work - it omits a couple of notes that are problematic to place. So by using Bm blues, you're taking a bit of an easy way out! Put te missing notes back into the set you could use, and it'll give you even more to play with - literally!
    – Tim
    Dec 29 '20 at 18:04
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    There are thousands of such resources, but that's not what we provide on this site. Homework time!
    – Tim
    Dec 29 '20 at 18:42
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    @AbelTom in my (probably slightly undecuated opinion), the idea with guitar is that you know what a major and a minor pattern look like, starting on the low E string and going through down to high E. You learn that scale, memorize it, internalize it, and do the same for the major and minor scale across a single string, and then possibly start trying to learn (or figure out on the fly) the same scale but starting on a different string - say the D string, and learn the major/minor scale both down and up the strings.
    – TKoL
    Dec 30 '20 at 10:15
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    Internalizing it even just from low E down to high E gives you so much flexibility, because you can move that pattern anywhere. Of course really good players have internalized it much more deeply than I've described, but it's a good starting point
    – TKoL
    Dec 30 '20 at 10:16
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A basic thing is spell the chords (correctly) then put the letters all in order...

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

A B C# D E F# G A

...then look for a key/scale. In this case you have F# and C#. If you know your key signatures, you will recognize that's D major or B minor.

Keep in mind the importance of knowing key signatures. You are working by trial and error, probably because you haven't learned key signatures. If you really want to identify scales and keys, you must learn them.

Another approach is to use basic harmonic patterns. You need to know important diatonic chord patterns to do it - the circle of fifths progression and either II V I or IV V I cadences in major and minor keys is the essential stuff to know.

Two major chords with roots separated by a whole step occur in only one place within diatonic harmony. It also happens the chord on the next root up a whole tone will be minor (in diatonic harmony.) Those are clue to start zeroing in on the scale/key/tonic. We know the three chords fit a basic diatonic pattern.

Ultimately you want to determine the tonic, the central tone of a key, starting tone of a scale. Sometimes that can be tricky. Music is sometimes ambiguous about key, mode, etc. A lot will depend on the style conventions of the music. I think the style you are working with is probably rock, and that helps us.

♭VI ♭VII i is a very common pattern in rock music. By way of contrast something like ii6 V I is a common harmonic formula in classical music where the V chord is critical for determining a key. Rock music very often eschews the V I progression and does other things ...like ♭VI ♭VII i.

If we consider B the tonic, then we could have...

Bm: ♭VI ♭VII i

It's very helpful that you gave duration for the chords, you specifically have...

Bm: |♭VI |♭VI |♭VII|♭VII|i |i |i |i |

...the longer duration of Bm lends weight to calling it the i chord, the tonic chord.

So, the "scale" is B minor.

Notice I put "scale" in quotes. It's probably better to think in terms of B is the tonic, or the tonality is B minor, and a whole variety of scales and embellishments of the chord tones could be used.


From comments:

I tried the B blues scale? And it sounded really good. Is that a major or minor pentatonic scale? Speaking of outside Notes . Notes in B Phrygian dominant scale did not seem to fit quite well.

B C D# E F# G A B

This is where the key signature knowledge - and learning the gamut of letters by thirds and perfect fifths - will work for you. Tetrachord knowledge helps with this particular one.

Phrygian mode is characterized by a lowered second scale degree, a half step above the tonic. The major and minor scales don't do that, they have the second degree a whole step above the tonic. So phrygian is basically ruled out from the start.

Also, phrygian dominant starts with a harmonic tetrachord and that contains a major third above the tonic. This makes phrygian dominant a bit of an odd bird. It sounds minor-ish, because it's a mode of the harmonic minor scale, but it's tonic chord is major. The chord progression uses Bm. Phrygian dominant's tonic B major chord contradicts the tonic of the chord progression.

Specifically there are two points of clashing: the C of the scale and C# of the A chord and the D of the G and Bm chord against the D# of the scale.

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Here is a web page where you can enter a chord sequence, and it tells you which scales fit those chords.

http://www.micrologus.com/tools/online_harmonic_analyzer

You can do something similar in your mind (and it becomes very fast with practice) by following these rules of thumb:

  1. Figure out the parent scales of each individual chord.

  2. If the same parent scale fits multiple consecutive chords, it's probably the most logical scale to use.

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  • A parent scale will only fit one chord (and its relative). And considering minor scales, there's plenty to trip over. You're not saying Bm scale = A scale = G scale, surely?
    – Tim
    Dec 30 '20 at 10:29
  • That thing says tonal centers of D and A. The OP and others with similar questions simply need to learn harmony from practice and a modest amount of theory. You shouldn't direct people to something that doesn't work. Dec 30 '20 at 13:46

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