I think you messed up a little here - if you bought these on someone’s recommendation - either the advice was old or they haven’t been in the hobby for a while.

I agree with other comments about it being better to consolidate and buy one good headphone rather than buying multiple cheaper ones.

My 2c - return everything but the APP and get a good Senn open back (HD6X0 or HD560s) and get a different IEM - something like a Hexa is like endgame for most people for $80)

I just saw DMSs video on these. While I don’t trust his opinions that much, he seems to suggest that the tuning on these might be better than even the IE600 which was definitely high praise. @OP how do you compare these to your IE300? I already have the IE600, but I’m itching to get one out of curiosity….

My guy Linus did a video roasting this https://youtu.be/5WJak0Y7X80

Made in China doesn’t mean lower quality. 90% of consumer products are manufactured in China including Apple. Quality is purely commensurate with quality of material, design and manufacturing (including QC). This is purely negligence and a cost cutting measure on Audeze’s part. Lower priced or not, it’s their brand and their product; if they can’t stand behind it, it’s a problem. I won’t trust them with their higher priced stuff either

For real - the only reason I bought the mojo was how cool those RGB marbles look.

I think one reason could be that the position of your ears inside the cavity affects the sound a lot (I've seen this to be esp. the case with focals) - and since people's ears are different, having oval/circular pads with some wiggle room assures that everyone gets optimal sound.

I have a (bad) habit of storing boxes of my gear in the attic and sometimes it pays off - like selling them on marketplaces with the box obviously gets more resale value.

But in this case, I would’ve thought your invoice from Amazon should’ve been enough. I’ve seen a lot of gear with no info like S/No written on them, which means it’s just benefit of doubt, or honor system when it comes to establishing whether something is in warranty.

And yes, it does seem like a deliberate attempt by them to reduce the number of repairs they service in warranty given how they denied your claim. Or at least an extremely concerning oversight

Personally I keep both with me too as they serve different purposes. Although I do believe even strictly SQ-wise too APP is pretty decent and stands it’s own with sub-100$ IEMs.