Originally Posted by: kvsealegs

I am not certain that I understand what modulation is.

[/quote][br]This tutorial covers the basics of modulation in simple chord progression.

https://www.guitartricks.com/tutorial.php?input=876

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Originally Posted by: kvsealegs

I borrowed another persons ear, and they agreed that the progression sounded correct and If I were to play the sequence say in the key of F and play the B as B flat, it just doesn't work.[/quote][p]I'm guessing it doesn't sound good to you because you aren't starting or ending on the tonic or relative minor. The G is also a modulation in the key of F so that's another twist!

[br]For example, try those chords in this order:

[br]F / A minor / B-flat / G / C / F

I / iii / IV / VofV / V / I

That's how you might use some of those chords to strongly indicate you are in F major as an example.

Originally Posted by: kvsealegs

I will assume that it is most closely playing the key of C with the B minor closely assimilating a B dim which I don't understand anyway.[/quote][p]Maybe. I know that until you've listened to some (or a lot!) of music with those kind of chords, it's hard to hear how they fit or even that they sound good.

[br]The other interesting thing about that progession is that by starting and ending on A minor you are setting up an expectation that everything will relate to those chords no matter what else you do.

[br]And "force fitting" a B dim or half-dim in before the A minor doesn't really serve standard functional harmony because the B dim is a sub dominant that typically leads to the V (E), before going to A minor.

[br]Try playing this & see what you think.

[br]|-----------0---------------------------------|[br]|--1---3---0----1---------------------------|[br]|--2---2---1----2---------------------------|[br]|--2---3---2----2---------------------------|[br]|--0---2---2----0---------------------------|[br]|-----------0---------------------------------|

That's a typical way of using the B half-diminished to function as a sub dominant to get to the dominant: i - ii half dim - V - i.

Why did the B minor sound good (or better) to you? Likely because the B minor is a more stable sounding chord & the next & last chord is A minor.

Originally Posted by: kvsealegs

In looking up modulation, I found another term tonicization, which is likely the occurrance.

Sure, tonicization is essentially a very brief modulation. But the term tonicization means another key is explicitly sounded by voice motion & dominant (V) or diminished (vii dim) chords leading to a root. That's not happening in your chord progression with the B minor.

https://en.wikipedia.org/wiki/Tonicization

[quote=kvsealegs]

As I understand it, modulation would follow the key change, as the key changes in "without you" by Nillsson.

[p]Yes! And that song also uses tonicization in the verse.

E (I) - G#min (iii) - F#min (ii) - G#7 (V of vi) - C#min (vi) - B (V) - F# (V of V) - E (I) - B (V)

So, you're in E major. Then you've got the tonicization of the relative minor:

G#7 (V of vi) to C#min (vi)

And of the dominant!

F# (V of V) - E (I) - B (V)

Notice the E in between is just delaying the arrival of the V of V to V.

[quote=kvsealegs]I also have found E G D E to sound fine when played in sequence.

Sure, you can get just about any series of major chords to sound good if you play or expect a melody that works with all the chords.

That's more of a modal approach than any kind of functional harmony. Those are typical chords of pop rock & blues influnced songs. For example:

Please Please Me (Beatles)

Stepping Stone (Monkees)

There are probably hundereds of modern examples. Those are just the first two that occured to me because it's Sunday morning, I'm on my first cup of coffee & mostly I am old. :)[br][br]

Those chords are pretty closely related, the B is a common tone between the E & G, then the D is a common tone between the G & D. It helps to look at voice motion, how the notes of the chord move from each to the next.

But the glue that really holds them together is the melodic voice motion that leans on the chord tones as the chords change. Moving the melody from G# to G while the E moves to G is a great & fun sound. Then, the G# moves to F# on the G to D chords.

Or you could just stay on B for the E & B, then down the E minor penatonic until you get back to the E. That's the melody of Stepping Stone.

There's no tonicization there. So, it's just modal modulation. Sometimes called modal interchange, or borrowed chords.

https://en.wikipedia.org/wiki/Borrowed_chord

Essentially they are just chords that are not in the same key, but share enough common notes that you like the sound of them together. And of course there's a potential for a melody line that snakes through them!

[quote=kvsealegs]At first , I was eager to think that perhaps it was modulation, especially in the Am-F-G-Bm-Am, starting in the key of C and modulating to G.

Well, it still could be thought of that way.

Amin (i) - F (bvi) - mod to G (I) - Bmin (iii) - Amin (ii)

But the problem here is two fold:

1. Unless you have a melody that really strongly indcates this, there no reason to force fit those keys.

2. The chord progressions don't center on or lead to C (no G (V) > C (I) motion) or G (no D (V) > G (I) motion).

Without some melodic or chordal reason to think you are in C or G, it doesn't really clarify or illuminate anything. Even though those chords belong to those keys.

Without more info I'd say the whole thing is in A minor & the B minor is a borrowed chord that substitutes for a V chord.

You might find my tutorial on the basics of functional harmony & circle of fifths useful if you are really interested in how voice motion works & chords function.

https://www.guitartricks.com/tutorial.php?input=495

https://www.guitartricks.com/tutorial.php?input=835

Hope this helps!