Why does this sound like it does? (Guitar and music theory question)
November 13, 2015 2:56 AM   Subscribe

Why is it that when staying in the same key, when the backing band / bass changes in some way, the notes that "feel right" on the guitar change? (Lots more inside)

I've tried to learn about music theory, but I've never really been able to understand it. At the same time, I'm learning to play guitar, using (in part) Rocksmith (a game) (you don't need experience with this game to answer the question, though). Rocksmith has a "Session Mode" where a generic backing band plays and you can solo over the top. You pick the scale and key and a few other things, and play what you want. On-screen it shows you the notes in the scale you're playing. Here's what it looks like.

If you look at the top figure, you'll see that there are all the notes in the scale, but certain notes are highlighted. When I solo, any note I hit in that scale sounds good, but the highlighted ones sound extra good. It sounds good to play a note next to one and then resolve to it, or bend to it, etc. So the first part of the question is: what are these notes? How are they decided? Which leads to the next item, which is that after noodling for a while, the backing band will change...something. The bass and other backing instruments will make some change, and then, if you look at the second or third figures, you'll see that the scale is the same, and the key is the same, but the highlighted notes have changed. Now these new highlighted notes sound really right, and not the ones that were highlighted earlier. So what's going on?

I realize this is all music theory 101, but I just can't wrap my head around what I've read about music theory. Hopefully this actual real-world experience and y'all's help can break that barrier and make something make sense.
posted by Bugbread to Media & Arts (11 answers total) 14 users marked this as a favorite
Best answer: I don't understand the Rocksmith display, but I'm guessing those are "chord tones". Here's a brief description so you can google a better answer:

The backing band is playing a *chord progression*. That means, if for example the key is C major, they would be playing some chords that come from that scale (C major, D minor, E minor, F major, G major, A minor, B diminished) in a particular order. For example, the chord progression might be C major / F major / D minor / G major.

So while the band is playing the first chord, C major, the notes of that chord (C, E, and G) are going to sound particularly good in your solo. Those are the *chord tones*. You don't want to play them exclusively, that would be boring, but they're good notes to emphasize or land on.

When the band switches to F major, the chord tones are now F, A, and C. The G that sounded good a second ago is now a whole step away from the chord tones (F and A) so it sounds a bit off.

The band then moves to the third chord (D minor) and you have different chord tones to work with, and so on.

Hopefully this will give you a rough idea...
posted by mmoncur at 4:07 AM on November 13, 2015 [2 favorites]

Response by poster: Okay, that makes a lot of sense. So I tried something out: I turned off all instruments except for drum and bass. The bass is only playing single notes, so there should be no chords. Then when I played along, I noticed that this was true 90% of the time: The highlighted notes, going from the note being played by the bass, were the first, the third, and the fifth. So if the bass was playing a C, the highlighted notes were C, E, and G, as you said, even though the bass wasn't playing a "chord" per se.

Ah ha! I thought. I've got it! But then, this happened.
(Oh, regarding how to read this: the top (red) line is the low E, and the bottom (purple) is the high E. So the boxes, indicating the notes in the scale, are [C, D on the low E string] [E, F, G on the A string] [A,B,C on the D string] [D, E, F on the G string] [G, A on the B string] and [C, D on the high E string]. So your basic C major scale. And the highlighted notes are the "sweet notes", so in this figure, they are D, F, G, B, D, F, G, B, D.)

I don't remember what note the bass was playing, but:
If it were the D, then the highlighted notes would be the 1, 3, 4, 6.
If it were the F, then the highlighted notes would be the 1, 2, 4, 6.
If it were the G, then the highlighted notes would be the 1, 3, 5, 7.
And if it were the B, then the highlighted notes would be the 1, 3, 5, 6.

So this pattern differed from all the other bars. My guess is that the bass was playing the G, so the "sweet notes" were the 1, 3, 5, and 7. But why did that 7 appear (if that's what it was)? Why wouldn't a 7th (whatever the 7th lined up to, of course) sound good in every bar?
posted by Bugbread at 4:51 AM on November 13, 2015

Best answer: Part of this is that you're so familiar with this chord progression you can "hear" it even when no one is playing it. Also, C E G outlines a C major chord and you can hear that even if the notes aren't all played at the same time.

I'm not sure what the Rock Band 7 lines up to, note-wise, but the 7th note of the scale, for example, "leads" back to the tonic. In western music (classical and popular) we tend to want and expect that 7th note of the scale to "resolve" back to the root of the scale, the tonic.

Additionally some intervals (even just between you and the bass) will feel less "stable" than others - this has to do with the way sound frequencies work but, for example, an octave and a fifth are very stable and comfortable sounding while tritones (one half step smaller than a fifth) and seconds (two notes right next to each other) feel like they need to move and can be unsettling.

This might actually be a great time for you to go back and look at some more formal music theory materials, now that you're getting an intuitive feeling for it.
posted by mskyle at 5:30 AM on November 13, 2015 [1 favorite]

Best answer:
And the highlighted notes are the "sweet notes", so in this figure, they are D, F, G, B, D, F, G, B, D.)
Did you link to the right image? I see an F major chord (C, F, A, C, F, A, C). Ignoring that....

Anyway, G, B, D, F is just a G major chord plus a minor seventh. People call that a "G dominant 7th" chord, or just "G7". So, yes, that's a G chord, so you're probably right that the bass was playing G.

The 7th is a little more "dissonant" than the other chord tones, and 7th chords are a little more dissonant than triads (like the other chords).

So even on this chord that F may sound a little more dissonant/tense/unresolved compared to the other chord tones in the G7. It feels more like a question waiting for an answer and less like a place to stay, if that makes sense. You can try playing 7ths on the other chords too, but yes they'll probably sound even more dissonant, like they're notes to pass through along the way to someplace else rather than notes to land on.

Playing around and listening as you are is good, you want to get the sound of those different chord and scale degrees in your head to the point where you can hear a melody and know which notes they're playing. As part of this, it's also *really* good to practice singing these different notes. (You don't have to be a good singer, just learn to hit the notes--it's a good way to train your ear.)

it's also useful to learn all the language people use to talk about this stuff, if only as a way to communicate with other musicians. (So if a bandmate says "we're going to play C for for four bars, F for two bars, then G7 for two bars", you know what they mean.)

And, yes, music 101 would literally be a useful class if you can sign up for something like that. They'll make you practice spelling chords and intervals, learning to identify them by ear, writing them in standard music notation, etc.
posted by bfields at 5:31 AM on November 13, 2015

Response by poster: bfields: "Did you link to the right image? I see an F major chord (C, F, A, C, F, A, C)."

Whoops! Sorry, here's the right image.

bfields: "You can try playing 7ths on the other chords too, but yes they'll probably sound even more dissonant"

I'm curious, why would a 7th on a C chord (a C7?) sound more dissonant than a 7th on a G chord (a G7)?

But that's just a bit of a side question, really.

Mmonkur, mskyle, bfields, thank you, you've expertly answered my horribly formed main question ^_^ I was hoping this would serve as a bridge between the stuff I was reading but not getting and the stuff I was viscerally feeling but not understanding, and, yeah, it's all starting to click now. Awesome!
posted by Bugbread at 5:45 AM on November 13, 2015

Here is an example. Suppose you are playing in the key of C, over a C major chord. You can play in the C major scale there. But some of the notes from the scale, as you say, sound better than others. The chord tones C, E, and G, for example, are strong. Consider the note F. Sometimes this is called an "avoid tone" because it does not sound very good to stay on it or to emphasize it. It clashes with the E, the major third of the C chord, which it is one note away from.

Now suppose the band plays a new section, a little thing that goes from Dm to G7. You can still play over that with the C major scale's notes. But the notes now have a different weight. F, which you wanted to avoid on a C chord, is now a strong chord tone of the Dm chord, and it's the dominant seventh of the G7 chord. F now is a note that really defines what the harmony is, and it can be used much more prominently.
posted by thelonius at 6:05 AM on November 13, 2015

Best answer: OK, that image makes more sense!

G7 vs C7, uh, there's no simple answer:

If you're in the key of C major, then actually you probably wouldn't play a C7 at all, you'd play a slightly different chord with the 7th one half-step higher, at B natural instead of B flat, and the chord would be called a "C major 7th", or "Cmaj7". The C-to-B interval is a major (as opposed to a minor) interval, and maybe a little more dissonant. So that's literally a different chord.

There's also the question of the context of the chord: within the key of C major the two chords (C and G) have different functions--the C is the "tonic", more sort of a home chord, and G is the "dominant", which is usually thought to need resolution to the tonic.

And it's kind of more natural for the dominant chord to be more dissonant, and the tonic chord to be more consonant.

The actual C dominant 7 (C7) has a B flat in it, and is the dominant in the key of F. (Then again those earlier images claim the song was in C mixolydian, which does has a B flat, and where C7 would be the tonic chord, I guess? I don't know what to say about that.)

Oh and if you're playing anything blues-influenced then you tend to lean on the flat 7th a lot and just use dominant-7th chords all over the place....

This is all a lot like language: you think there are grammar rules, but if you ever try to write them down you find out they've got a lot of exceptions and that when you're done you've only described one particular way of talking or writing, and that most people (whether they know it or not) actually switch the set of rules they're using based on context.

So it's all sort of fuzzy and depends on what kind of music you're playing, because this stuff all evolved by different groups of people just trying to communicate with each other musically and then attempting to make sense of it as a coherent system after the fact.

Which doesn't change the fact that it's still useful to know all this stuff if you want to talk about music with other musicians.
posted by bfields at 6:11 AM on November 13, 2015

Response by poster: bfields: "Then again those earlier images claim the song was in C mixolydian"

Yeah, the screenshots were from two different sessions. After the initial explanation I started a new session in C major because I'm more comfortable working with and discussing it.

Anyway, thanks everyone. I could keep throwing questions at y'all till the cows come home, but I think I've got a good enough idea that I can go back to reading stuff about music theory and this time make some sense out of it on my own. I owe y'all!
posted by Bugbread at 6:51 AM on November 13, 2015

I'm so happy because I've just recently "unlocked" the ability to see 9ths's and 6's while soloing and am playing those wherever possible. At the moment if I had to make up a cheat sheet for "good chord tones in jazz standards and bossa nova":

1,3,5 : start here, visit them but don't end up here (too basic)
flat 7: any dominant chord; or blues chords
maj 7: most major chords; good place to end; restful, airy. (pass through on minor chords)
6: most major chords; good to end (possibly via maj 7). Bit more tension. Makes a minor chord real moody.
9: yum on major chords and minor chords
4: Pass by or through on major chords but in minor it's great, not to mention sus chords.
b5, #5 & b6, b9, #9: diminished and half diminished and some dominant chords. To get into these spicier, rarer chord tones I've been trying to wrap my head around minor iiØ-V#9-i progressions.
posted by yoHighness at 5:31 AM on November 14, 2015

Glad to help! If you want to go further I highly recommend this book: Music Theory for Guitarists. Along with a good guitar teacher, this is the book that made a lot of music concepts "click" for me.

Also, Music Theory for Musicians and Normal People has some fun poster-style lessons, although they're more oriented toward classical music.
posted by mmoncur at 4:18 PM on November 14, 2015 [1 favorite]

Slightly late to the conversation, having been away for a couple of days, and I can't answer your questions directly, as my knowledge of musical theory is really not much more advanced than yours. But I did want to point you at Howard Goodall's "How Music Works", a series that aired on Channel 4 in the UK in 2006. Goodall does a tremendous job of explaining this kind of stuff in a manner that's accessible to an idiot like me but not dumbed down. If you can track it down I recommend it. (If you can't, memail me and I may be able to help)
posted by kxr at 2:06 AM on November 15, 2015

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