I just tried your suggestion, but at least on a first attempt I can't get anything to appear.

Thanks for the idea, though!

My inner ear is nothing compared to a good composer's, but it's waaaaay better than my mind's eye, I think mostly due to years of heavy musical practice routines.

There was one memorable occasion when I was able to page through a set of flute/clarinet duets and actually hear in my head how they sounded based on sightreading the scores mentally.

I was playing a lot back then and doubt I could do it now. Two monophonic instruments also helped - I can recall individual voices or instruments fairly well, but whole arrangements much at all.

not whole arrangements, is what I meant to type.

This was one of the things that convinced me aphantasia is real (and that it's how my brain works).

I was concentrating very hard, trying to visualize _anything_ and suddenly managed to imagine a green blob. I can occasionally visualize purple as well. It's so incredibly vivid though... It makes me genuinely sad to realize most people can do that (and so much more) at will.

I don't "hear" any more than I "see" in my brain.

I definitely have aphantasia - it makes meditating both easier and more difficult. I don’t get to traverse beautifully intricate mandalas but I can very easily engage in focused metta without distraction. On occasion I will see a blue light that fades in and out.

Keep practising. Try imagining the blob turning into simple shapes. Try to imagine what the blob would look like from the other side.

I have, trust me. Most nights lying in bed I'll spend at least a little time doing exactly that, with little change (that's how I figured out I could make it purple though)

Don't do it when you're trying to fall asleep, do it when you're bored and have nothing else to do. I think I'm really good at visualizing because I spent most recesses by myself imagining I had friends.