Why does the relation between E major and Ab major feel especially connected?

Question

I find that whenever I improvise in E major, I naturally move back and forth between E major and Ab major key areas. It's like E major and Ab major feel especially connected in a way that say Bb major and D major do not feel as strongly connected at all but rather extremely contrasting. Both of those pairs are same # of accidental pairs, but of the 2, the E major and Ab major feel more closely knit than Bb major and D major. Here are those 2 pairs of keys on the circle of fifths:

And as you can see from the thickness of the lines, the E major and Ab major feel more connected to me than Bb major and D major do, despite the same relationship between both pairs of keys(Major chords a major third apart). This progression is an example of what I might use to seamlessly go from E major to Ab major:

E major -> B major -> Eb major -> Ab major
E: I          V          
Ab:                       V           I

Of course, it probably wouldn't be quite that simple. Like B major might be followed by BM7(which would make there be 2 common tones between it and Eb major) or there might be some minor chords in between 1 or more of these chords, but these 4 major chords might very well be the basic progression that then gets harmonically embellished. I know that some chromatic mediant relations are stronger than others, and this 2 major chords is probably one of the strongest out there.

But still, why do E major and Ab major seem to be more connected than Bb major and D major? Is there just something about the range from 4 flats to 4 sharps that makes everything there feel connected to everything else, like perhaps the rarity of pieces in these keys, especially on the sharps side?

Answer 1

Objectively, there should be no difference, since E and Ab(G#) majors bear the same relationship as Bb and D majors. Allowing, then, it's a matter of personal perception/preference, I propose two possibilities:

1. You prefer the shift from sharps (E major) to flats (Ab major) over the shift from flats (Bb major) to sharps (D major): There is a feeling that is not uncommon among musicians that flat keys (or flatted notes) are somehow gentler or more soothing than sharp keys (or notes). I often find flat keys easier to read than sharp keys, even when dealing with the same number of sharps or flats, and other musicians have described the same phenomenon to me.

To test: Try improvising in B/Eb (sharp to flat) and and F/A (flat to sharp), to see if a preference emerges and, if so, whether it matches the proposal.

2. The range on the keyboard (you're a pianist, yes?) covered by the E/Ab scales has a more pleasing sound to you than the Bb/D range: Imagining, for example, you improvise in E/Ab using the scales starting just above middle C; whereas you improvise in Bb/D using the scales starting a tritone lower. Perhaps it's just enough lower that it doesn't sound as good to you as the range covered by E/Ab. Similarly if you improvise in Bb/D a tritone above the E/Ab range you use.

To test: Try improvising over scales closer intervalically to the scales in question. So, for example, D/Gb and A/Db versus E/Ab and Bb/D. See if the range similarities have an impact or not. (Note: I specifically chose keys that are consistent with the sharp/flat change of the keys in their range.)

Answer 2

There may be a historical connection.

As discussed in "The A♭–C–E Complex," these major-third key relationships are most common within those three keys, and not, for example, between B♭, D, and F♯.

The claim that the author makes—and I find it very convincing—is that these major-third cycles were most in tune in earlier practice with these three keys because they have the least number of accidentals in their accidental-heavy keys. And because historical tuning systems often privileged keys with fewer accidentals, this particular major-third cycle was the best, most in-tune option. The cycle with D♭ has five flats in its most accidental-heavy key (one more than A♭), your B♭–D–G♭ cycle has six flats, and the remaining cycle has B major with five sharps.

You're presumably not using these tuning systems anymore, but there may be a subconscious connection here where you sense that these keys were more commonly used than B♭ and D.

Answer 3

To compare your impression of E - Ab (=G#) with Bb - D you must play the progression Bb - F - A - D.

Will you feel still any difference?

I bet that no!