I heard this in another sub, that only tuning matters for IEMs but I’m not seeing it.
Aside from tuning what parts are giving advantages? The housing, the drivers, the materials used?
Example, the truthear nova ($150) is tuned nearly the same as the moondrop variations ($520). Does that mean they would have the same sound quality?
Exactly. Just because a frequency sweep “looks” the same on a graph, does not mean those frequencies are delivered in a good or bad way to your ear.
FR is a best case scenario. Doesn’t answer for example if other frequencies will be drowned when bass is present. This is common weakness of DD but almost not present with planars