I have no idea why Apple made the decision to use the same file extension--m4a--for AAC and ALAC. Is your file definitely AAC? The file size should be around 10MB.If so, this looks to be a Shanling M1 killer (for those of us who have iTunes libraries).
Thank you for your assessment.I really liked the sound signature of the 712s when I owned them, but I get the impression the IX will not get close to the bass on the 712s; others here have said bass is not the strength of the PF series, rather, it's the midrange.And yes, I do understand what you're saying other than the Mojo having soundstage limitations ... I've not had this experience.
Any warranty issues would be handled by the seller. JVC USA likely wouldn't honor any warranty since the FW01 is not made for this market. Frankly, other than audionewbi's issue with the back cap coming off, these are pretty bulletproof, very unlikely with proper use you'll have any problems. Just make sure the seller will take care of any warranty issues should they arise.
I don't have an answer to your question, but I do want to congratulate you on your purchase. I've had my eyes on the PF IX for awhile, so I'll be interested in your observations, especially regarding the bass performance.