It is the first time that I realise and would like to share it with you here that the APM's sound is kind of veiled. So I can finally sympathise with and understand people here and elsewhere who do not like their sound signature that much. I have used my APM to listen on one of my music pieces on which I was working lately (mainly recorded on Logic Pro using midi as well as analog sources) and since I know very well all the details and sounds' extensions I am in a position to be an accurate judge. So the APM is presenting a rather dark copy of my piece, which when I hear on monitor speakers, or even on some BA iems like my Shure Aonic 4 (hybrid DD and one BA), is giving me a ton more details in the synths tails, in some drum sounds, voices etc. Some background sounds also are completely mute on the APM. If I was mixing on the APM I would certainly use eq to elevate certain frequencies, which seem absolutely fine and clear on my other speakers, thus leading me to mistakes in the final mix. I think this is the fate of all elevated bass headphones. You cannot find easily a headphone with such a deep a punchy bass to combine with full mids and treble details presentation. It turns out to be a veiled and dark sound, certainly missing out on the details of a music piece. Apart from the sound though, it's a very good headphone, sturdy, comfortable, with high quality materials, having of course also all the benefits of Apple's chips, Spatial audio, perfect ANC etc. But for sound alone, it may not cut it, especially for audiophiles and people who like a resolving presentation as well as a detailed and accurate sound. It was for sure a surprise for me, on my own music, and certainly kind of disappointing since it is not a cheap item, but ok, it certainly has its uses...
Edit: Of course another question would be where does my piece sound better? Well, its dark and veiled copy of the APM is not bad, but it certainly is not accurate. The more balanced/bright speakers present clearly what I made, when the APM presents a more laid back and less fatiguing sound. So, veiled is not bad (for sure goes mellower on the ears), but the problem is with accuracy which is not there.