sensitivity vs impedance vs balance vs confusion

[Enzyme]

ok long story short im confused about headphone specs and how to match the perfect spec setup for my j3.
this issue came up in another thread
Cowon J3 FAQ page 9

this topic is not j3 specific but is here to help the experienced teach us less informed folk.
if we could keep it as close to a mathematical formula as possible i'd be most gratefull

for the click lazy here's some quotes from the previous thread:

I found that some people say that Cowon J3 is not able to drive BA IEM with low impedance, is this true?

and if it's true, what is the minimum impedance that is still within J3's ability?

although (and i lack knowledge on this) i hear the sensitivity of the phones has more to do with the output levels than the impedance.

I've heard that, too. Apparently impedance isn't a good reference to how hard something is to drive.

My Shure SRH840s are rated at 44Ohms, and the J3 has absolutely no trouble with them at all (I can generally keep the volume at 14).

i know i had a few fun moments as a kid plugging in house speakers (4ohm)to a car amp(8ohm) n seeing em go up in smoke,,or it was the other way around...hazey days

well out of curiosity i checked up on the specs

the ue10's are Sensitivity: 117 dB
the dt880's are Sensitivity: 96dB

the dt880 are driven much better by the j3, especially noticeable in the midrange oomph (lack of a word), so im guessing that's the issue.
not sure how to describe it, except that the ue10's have loud enough highs to hurt my ears, as do the dt880's (very slightly less so)
the bass levels seem similar on both, but the midrange in the ue10's was a huge flop for me, lacked emphasis (thats the word) the dt's are loads better, just lacking slightly which is annoying me, i'd rather not eq if possible.

the confusing (maybe even clarifying) part is that i checked the specs on the triple.fi 5's
(the s9\j3 runs them very loud with no issue's other than overall sound quality)
they're sensitivity is 115dB but the impedance is 13 Ohm

so i guess we need to find an equation of some sorts that tells us what's what (im not the best at mathematics) and apply that to the j3 somehow..

now i just need to be brave enough to go on abi and ask for more amp advice relating to this after the last brawl ><

would be great to know the ideal mix and how to achieve a boost if needed.


[edit] also checked the specs on the shures
Sensitivity (1kHz)
102 dB/mW
Impedance (1kHz)
44 Ω


n that seems to just throw sht in the fan. maybe they are just generally better balanced or less demanding in some respect. but i can only vouch for the dt's and ue's as i have all 3 and im a picky s.o.a.b.

highly confused....let there be discussion ><