rules for switching scales?

[guitarded]

so ive been playin guitar for around 7 years and taught myself mostly thru friends and the interweb. im wondering how to switch between scales during a song. say im playing e minor can i switch to e major without it sounding too off? what about e minor to f minor? or e minor to a minor since theres only one note thats different? i'd really like to know because this metal band im in right now likes to bounce between different scales pretty much every riff...is this a bad thing? should we be using the same scale throughout most of the song?

[silent-storm]

There are no rules...you can switch scales as often or as little as you wish. Further down the road you may want to have an intricate knowledge of how one chord voice leads to the next and use that to determine which scales to use, but for now there is nothing saying you can't use scale X over chord Y.

Sometimes it makes sense to switch scales for each chord, which can sometimes be a different scale every beat. But sometimes it makes more sense to stay in the same scale for longer.

Some theory knowledge can help, such as recognizing chords that can use identical scales. Like if you see Cmajor - Fmajor. F major is in the key of C so you can use C major for both, of course depending how long you stay on F major.

But it really just comes down to doing this as often as possible and using your ears in order to do this properly. Experiment with switching scales for every chord and then try and find a happy medium.

[Poparad]

Which scales you use are dictated by the chords of the song.


If you're talking about writing a progression that switches scales, yes, you can change to whatever you want and whenever you want. It's a little trickier to write something that shifts keys, as you have to be a bit more aware in how the notes of the chord voicings lead into each other so that it creates a smooth transition and not a rough, disjunct one.

However, if you're talking about improvising over a pre-existing chord progression, you are bound by the chords and must play scales that contain the notes of the chords. For example, if you are playing over an Em chord, the scale must contain the notes of an E minor chord (E G and B). Typically chord progressions are entirely within a single key, and this continuity of the same key lasting an entire progression is what holds the music together.

Now, if you want to create dissonant, harsh sounding lines, you can play the 'wrong' scale for the sake of creating tension, but even then you have to be aware of what the 'right' notes are in order to effectively use the 'wrong' ones.

[mattfnk]

depends on what kind of music you're playing really. With Jazz, sure, you want to be intentionally right, and wrong, and let your "wrong" notes realat and resolve to the right ones. With Rock though, or blues its a little different.
An A7 chord has A, C#, E, and G. Yet we all know how cool an A blues or penta scale sounds over it, with a C instead of C# in the scale. I switch between Minor and Major penta all the time over the same progression. You have to pick your spot though and realize it sets a different mood.

[Apple-Joe]

Playing ie. E major over an E minor progression will sound quite strange. E minor over an E major progression, on the other hand, would sound more familiar, especially if you've listened to a lot of blues. Still, this is also theoretically 'wrong'. However, that shouldn't stop you from experimenting.

When switching scales you've got to remember the chords in the background. You mentioned switching from E minor to F minor. I assume you meant switching from the one to the other while the progression stays in E minor. OK, let's compare the notes of the keys. E minor is derived from G major, which got the notes: G A B C D E F#. F minor is derived from Ab major, which got the notes: Ab Bb C Db Eb F G. If you now compare the two, you see that the only notes the F/E minor have in common are G and C. This means five new notes will be introduced when switching to F. Using this over the same old E minor progression will sound... very special.

If you're interested in using different scales over the same backing, I'd recommend creating a very simple backing track. The fewer the notes of the backing, the greater the scale choice will be. For instance, record a static E bass note, and you can play anything as long as E is the root; E major/minor/Phrygian/Mixolydian, etc. - you name it. If you play an E major chord, you can use E major as well as E Lydian and E Mixolydian. Or an E minor chord, then you can use E minor, E Phrygian, E Dorian or E Locrian. There might also be some obscure scales which will work, but I don't have the complete overview.

I hope you feel like experimenting a bit now, using different scales over the same progression - or pitch-axis as Joe Satriani would have named it.

[guitarded]

i meant pure rythm guitar like for making a song. like if i make a riff in E minor like say....

d----------7----9-------
a-7-10-9---10--------- this is an e minor pattern....can i flatten the f# to
e------------------0---- an f thus making it an a minor pattern?

do people do this kinda stuff? what about playing that mode in different spots? i guess what im asking is whats the best way to switch keys ina song? the less notes that are different the better right? b minor to e minor to a minor and so on?

[Apple-Joe]

If you flatten the F# to an F, you surely get the notes of A Minor, but as long as you keep on establishing the E note as the tonal center, as in your example, you'll be playing E Phrygian, which shares the same set of notes as A Minor. They are both derived from C Major.

Notes of C Major:

C D E F G A B - C Major/Ionian, obviously

D E F G A B C - D Dorian
E F G A B C D - E Phrygian
F G A B C D E - F Lydian
G A B C D E F - G Mixolydian
A B C D E F G - A Aeolian/natural minor
B C D E F G A - B Locrian

Do you see a pattern?

Exactly the same set of notes, but as a major scale got seven notes, you can build a new scale based on each scale degree, by using another note of the scale as a starting and ending point. Hence, as there are seven notes in a major scale, there are seven modes available. Another great aspect of this approach is that when you have written down the chords you can use in C major, you also know the chords to use for all of the modes of C major.

However, another great approach for the modes - to really see the difference - is to start with a scale, like you did, and then change a few notes to make it fit another scale.

For instance C major. Notes: C D E F G A B. Play it and listen to the sound. Then you re-arrange the notes so it fits C Dorian: C D Eb F G A Bb. Play it, then think about the sound. Re-arrange the notes to fit C Phrygian: C Db Eb F G Ab Bb. Do this until you've played all 7 of them, and compare the sound

As you can see, there is a lot to do if you just know the contruction of major scales.

[Roobs]

also, a little tidbit that I have found pretty cool: When playing over a major chord progression, it sounds really cool to switch between the major and minor pentatonics (and probably full scales as well). Lots of the old blues dudes would play minor pentatonic over major chords, gives it a cool 'sad on happy' tone.

[guitarded]

hmmm ok what i meant actually was switching keys....the rule is the more common notes the better right?

[Apple-Joe]

hmmm ok what i meant actually was switching keys....the rule is the more common notes the better right?

True. Also, a good method for modulating is to introduce the Dominant 7th chord of the new key. So, if you are playing in the key of C, after a while, play the D7 chord, which is the V7 of the new key (G major). You just pick the ii of your base key, and transform it into a Dominant 7th chord. It will be the V7 of the new key. However, depending on the base key and new key, you might want to incorporate a few extra chords in order for the modulation to sound smoother.