Greetings Sir Badger
For me music breaks down into integers. Just like maths you learn things forward then in reverse. Add then subtract. YOu should pobably be looking at training the ear to hear intervals before you start to classify the colour of chords. I started with singing. Can you tell just by one note what is is? can you say that thats a A 440 ? spend some time training your ear to think about the exact frequency. Play a C ... does it make you feel something? see something? a colour? an emotion? tie it to that which is already in the brain. For me the C is lime green. ok thats single notes
\lets go to intervals
sing somewhere over a rainbow. You now have an octave. you can sing it loud or sing in your head. just train your mind to the interval. sing the interval from different root notes. Now subtract one- sing c3 to b4. then c3 to a4. keep decending till you get to c3 to d3.
now see if you can sing random intervals. Sing a perfect fourth? Should all acquaintance be forgot and never brought to mind. there will be some tunes in your head that you can assign intervals to.
Sing C3 to C2 ... C3 to D2.... repeat the process until you get to the leading note C3 to B3... im presuming here that midi note numbers increment at the start of the A octave... and not at the C... which the probably do... so i may have added license to midi note nomenclature.
OK now lets add them together....yes it 2 note chords time. have someone play or make up a random midi file that plays 2 3 4 5 6 7 8 intervals ... see if you can determine what the two notes played together are. Don't just stick in c major now. Move to other keys and start to hear other colours.
Now move to other scales and repeat all those processes. Minor scales, harmonic and melodic and so on. up and down... you get the idea.
i copied air on a g string once. I played it in reverse so it wasnt so blatent.
there is a program called ear master school that i have found to be of benefit. It will train the ear to inversions of all chords with 3 notes or more.
with this you can start with groups of three notes. i used it to train my ear to flatted fifths and augments and 7 9 11 13 etc. It was a really good help. I should revisit this learning again soon. It enabled me to substitute these special chords in place of other chords in a melody. a minor sixth in place of a commonly used seventh chord adds so much more colour for example opens a world of musical possibility. It is fantastic help to training not only chords but rhythms, intervals, and sight reading. The latter is pretty dull of course but once again, its all maths. Music written on a staff is merely a frquency time graph.
best to you badger. Hope your tunes
Chord trainging takes a long time. I spent about 7 months using earmaster for about 1/2 hour per day until i could easily pick up that the chord was a minor 9 with a flatted fifth.