Hey Niklas!

Personally, I find the augmented chord confusing. It leaves you hanging in the air, not knowing where to go. Meanwhile, the diminished chord is unstable, making it difficult to stay in for a long time. You feel the need to leave as soon as possible, the need to go somewhere.

Thinking about these feelings is how I tell them apart.

Augmented sounds more open and stretched, and diminished sounds squished to me. It becomes more of a feeling than something you actively hear. Danzo's answer is also pretty good, I think.

Another note: The diminished chord sounds like a dominant 7 chord without the root note. It's the main cue I use when I need to distinguish it in isolation.

this is a struggle for me as well, but unlike Aug, the Dim exists among the scale triads as the leading tone triad (vii0), so I always try to imagine if the chord could serve in this role or not.

I'm still struggling with this. Best I hear for now is:
- Aug, if you imagine the top note down a semitone, the tension is resolved
- Dim, like a minor chord gutted of energy, extra flat (not musical jargon flat, but like a deflated tyre, not rolling anywhere easily)

for me the dim sounds like Dom7, it has a much more resolving character.

Use the Force :) Ok, seriously, Sheer repetition and blunt force trauma. I will literally pause and go back and forth a minimum of 10 times before moving on. Eventually I improved enough so i don’t hide in shame as much as I used to

thanks guys! at least now i feel less alone with my struggle haha guess i'll just keep on trying and try to implement your hints!

to me the dim chord sounds like it wants to lead to another chord. The aug just sounds off in its own world. Hope that can help?

I finally got past Chordelius level 8 (dim/aug). Level 9 (7ths) was a breeze, in comparison.