I believe that most of them do. As phase is crucial for proper x-o.
When your new UM-3ways arrive take a look on the inside. You'll find that tweeter is wired in reversed polarisation which suggest matching phases of drivers to avoid phase shifts.
I'm not saying UM doesn't try to match it (especially in absolute terms - as in wiring each driver the right polarity). What I'm saying is what degree of phase shift are they trying to avoid from the xover/multiple drivers itself? and
http://www.innerfidelity.com/images/UltimateEarUE700.pdf
http://www.innerfidelity.com/images/ShureSE535.pdf
Unless I'm misreading the charts for phase and impedance - it sure looks interesting. (60 deg shift in some places and varying by 10-60 degrees across the FR)
Yep, to me impedance and phase are 2 crucial parts I pay attention to the most when it comes to xo designing and transducer matching. Not to mention that trivial things like how drivers are placed inside the shell and tubing diameter also play quite an important role here as well, all together help tailor the final sound signature. That's why other companies like UE or Westone or JH don't offer this kind of service since it takes a great deal of time and efforts to tune a good/great sounding pair of iems.
eeeeh see above for UE.... I really don't know if many people can hear across FR specific phase shifts. It seems not everyone can even hear reversed polarity.
I'm sure we can hear 'prominent' tubing diamater issues or see the effect on the other measurements in similar charts, or filter issues BUT (if they're pronounced):
I can't really hear phase issues on blind testing as long as they're symmetrical between the two channels (did some on the http://www.audiocheck.net/blindtests_abspolarity.php site, so I can't really comment on that. )
I haven't tried taking a track or tones and applying an effect of gradually shifting phase where it might be easier to hear it .
I have a sneaking suspicion the impedance/phase graphs for the 4 way xover on my SM3x8 would look even 'more interesting'
>I'm not bashing UM's service here by any means, just wanna share my thoughts on this topic.
well, let me put it this way: I've had a problem before with the way the original reshell of SM3 sounded, and if you can describe the problem to UM, they'll fix it and take it on board for future reshells/designs. If you're with a local dealer it won't cost you much (not that $50 shipping to china via courier is expensive anyway). Just the time.