Hi HiFiHillbilly,
Very good question.
I have got these little monsters in my current team :
- Final Sonorous VI (Pads "A" / câble Lunashops hybrid 8 cores) + DAP iBasso Dx90 MM2 (FW Lurker)
- Campfire Andromeda v2 (Tips "Symbio W" M / câble Alo Reference 8 balanced) + DAP Aune M1s
- Noble Kaiser Encore (Tips "DSW v2" M-L / câble Penon hybrid 8 cores balanced) + DAP Aune M1s
I use all these devices exclusively in a nomadic way.
So the Final Sonorous VI is a full size headphone,
closed, and not the worst in the market lol
And... really, Andromeda's are in the same league about sound signature and results... just crazy amazing.
And the Kaiser Encore are more like... sort of... Sennheiser HD800 (not the "s" version), but in an iem way. Same feeling : just crazy amazing.
Anyway, I find that the full size headphone play at an other dimension, about the soundstage deployment : more air. Because it's over the ears, not in the ears.
However, this is also a known feature of the Final Sonorous VI (with "A" pads), so it could be wrong with other designs. Because the dynamic scale and soundstage both of the Andro's and Kaiser Encore are juste... incredible : no apparent limit, just the volume you can handle.
BUT !...............................................
1/
The tips are VERY IMPORTANT !!! You must find the good formula to get the best fit, isolation, seal. And it can be very tricky... Really, it can be a real concern... (with universal designs, and TOTL designs if you want the best and only the best)
2/ The pairing with the digital audio player is very important too...
For instance, you can read that I use a DX90 (heavily modded version) with my Final Sonorous VI, and an Aune m1s (balanced output) with my Andromeda and Kaiser.
For these ones, and particularly for the Andromeda's, the impedance must be very low, and the output completely clean, free of hissing.
So, "
can high end IEMs ever be as good as similarly priced headphones?",
My answer is "yes... but"
My 2 cents.