Music is completely relative and context dependent. There's no such thing as an absolute minor scale: it all depends on what has been and what's to come. It's hard to derive a strong tonality from just a scale, they're pretty ambiguous.
C major has the exact same notes of A minor, and C minor/aeolian has the same notes of Eb major/ionian (and 5 other modes with different qualities: F dorian, G phrygian, Ab lydian, Bb mixolydian, D locrian... all have the exact same notes).
Even if you think of C aeolian when playing you might be implying a different tonal center, depending on your emphasis, and therefore a non-aeolian progression.
Your ears can latch to any tonal center depending on exact phrasing. With no harmony there is no clear tonal center (and even with harmony, it's easy to switch between related modes, even unkowingly, because they have the same notes _and_ the same diatonic chords).
> But if I just play ascending thirds (R 3 2 4 3 5 4 6 5 7 6 R) in C-minor
Are you playing that in a 3/4 rhythm? (R b3 2) (4 b3 5) (4 b6 5) (b7 b6 R) the downbeats are R-4-4-b7 (no characteristic minor tones) your ears are hearing the minor tones as passing tones. Since aeolian has no leading tone (natural 7, one semitone away from R) the tonal center is even more ambiguous.
You might be hearing that as Bb mixolydian: (2 4 3) (5 4 6) (5 b7 6) (R b7 2), downbeats on 2-5-5-R which is _the_ canonical major jazz progression (ii-V-I). The phrasing implies ii-V (ambiguous if major V or minor v)-v (minor due to b7 of I being b3 of v, establishes mixolydian)-I. V-I is a pretty strong (if not the strongest) tonality indicator.
Bb mixolydian is a major mode, hence why it doesn't sound particularly minor to you.
Try playing the C minor with ascending thirds over a C harmonic minor _progression_ while emphasizing the V-i cadence and the characteristic minor tones (namely, b3 and b6). Notice I said harmonic minor progression, which has a leading tone to strongly stablish tonal center (which is what it was invented for).
C major has the exact same notes of A minor, and C minor/aeolian has the same notes of Eb major/ionian (and 5 other modes with different qualities: F dorian, G phrygian, Ab lydian, Bb mixolydian, D locrian... all have the exact same notes).
Even if you think of C aeolian when playing you might be implying a different tonal center, depending on your emphasis, and therefore a non-aeolian progression.
Your ears can latch to any tonal center depending on exact phrasing. With no harmony there is no clear tonal center (and even with harmony, it's easy to switch between related modes, even unkowingly, because they have the same notes _and_ the same diatonic chords).
> But if I just play ascending thirds (R 3 2 4 3 5 4 6 5 7 6 R) in C-minor
Are you playing that in a 3/4 rhythm? (R b3 2) (4 b3 5) (4 b6 5) (b7 b6 R) the downbeats are R-4-4-b7 (no characteristic minor tones) your ears are hearing the minor tones as passing tones. Since aeolian has no leading tone (natural 7, one semitone away from R) the tonal center is even more ambiguous.
You might be hearing that as Bb mixolydian: (2 4 3) (5 4 6) (5 b7 6) (R b7 2), downbeats on 2-5-5-R which is _the_ canonical major jazz progression (ii-V-I). The phrasing implies ii-V (ambiguous if major V or minor v)-v (minor due to b7 of I being b3 of v, establishes mixolydian)-I. V-I is a pretty strong (if not the strongest) tonality indicator.
Bb mixolydian is a major mode, hence why it doesn't sound particularly minor to you.
Try playing the C minor with ascending thirds over a C harmonic minor _progression_ while emphasizing the V-i cadence and the characteristic minor tones (namely, b3 and b6). Notice I said harmonic minor progression, which has a leading tone to strongly stablish tonal center (which is what it was invented for).