I have. Easiest if you use impulse response alternative visualizations such as Frequency Response and CSDs.
Transient is an engineering term that refers to the behavior of a system before it reaches steady state. This applies to analog and digital systems.
The mechanisms that affect transient response also affect overall tone, balance, soundstage, and so forth... not just drums.
Not sure why you think it's a fact that the LCD-2 has a "faster" transient response (an impulse response characteristic) than the HD650. From IF characterization, relative to the main peak of the impulse response, I think there is about the same or less energy in the HD650 past 1.5 ms than in the LCD-2 case.
Also not sure about "tremble matches well known headphone HRTF models", HRTF models vary quite wildly.
Roll-off in the tremble does not mean shorter or "blunt" transients. It may mean less low frequency transients and more mid/high frequency transients.
In the bass range, the LCD-2 is IMO superior to the HD650. But not in the mids and treble regions. I found the LCD-2s I heard slightly more recessed in the mids and lower tremble. Relatively uneven as well. There might also be some product variation. I also do not like the LCD-2s price at all.
You talk of all these measurements...it sounds like this to me. blah, blah, blah, blah, blah, blah.
Frankly transients cannot be seen in any of the measurements you state. I can only trust my ears...cymbals, snares, kick drums, piano key strikes, cowbell strikes, guitar plucks - these have an attack that gives away to me what might be going on.
If cymbals on the HD650 sound rough and grained - not like cymbals in real life, and on a Fostex T50 RP, LCD2, HD800, SE530, D7000, T1- regardless of treble amplitude produce a crisp real precise sound - like in a ride cymbal, it sounds so much true to life with minimal graining what can I hypothesise?
The only logical hypothesis is that on the HD650, the driver is not accurately tracking the electronic signal. If not, why not? On the other cans the definition on ride cymbal sounds correct regardless of amplitude, if so why so, we can hypothesise that possibly because the driver more accurately tracks the signal? Its not just cymbals either, it encompasses all of the sounds I listed before.
Planars are quick - the 80 dollar T50RP Fostex has far superior cymbal definition and piano key definition than the HD650 - regardless of poor housing or frequency response.
LCD2s recessed in the mids? you mean upper mids? upper mids being the same thing as lower treble. Regardless...what if I told you it doesn't sound all that recessed to me at reference volume. If one person is adamant that it is muffled and another person is adamant that it is not - who do we believe? Perhaps one is listening at lower volumes so it sounds muffled - how low? If lower than an actual performance level - or reference level, then this is void as neutral cannot be established below reference - we become subject to the loudness curves. If opposing views are presented at reference levels than we can hypothesise that one person is hearing the upper frequencies at a magnified level compared to the other. If so, why so? All these hypothesis are entirely falsifiable and falls within the jurisdiction of science. I do not have the equipment to falsify these hypothesis - but they are open to be falsified.
Your assumption seems to be that drummers merely bash on the kit with no consideration to their band members...and what if the leading lady would like to perform a ballad? The key aspect with band members is to listen very carefully to one another - not play to drown another out, this requires careful playing to matching volumes by everyone, we do this by listening carefully to each other...especially when hardly always only drumming to heavy metal - ask the leading lady, she likes to perform love songs all the time. Don't underestimate any member of the 5 piece band - they know the sound of their members instruments very well - and often switch positions if necessary. The guitarist often can drum, the pianist often can guitar - enough for practice to continue.
The whole idea of recreating music in the audience perspective is flawed - musicians play to themselves, not to you. In classical music - only the Maestro knows how an orchestral piece sounds - he conducts for himself, not for you.
The LCD2 is not perfect, but any planar to my ears are faster than most dynamics, and the best planars are faster than the best dynamics to my ears. Yes the HD800 has a smoother, more even treble response - it must, it is peaked there. But in no way to me do the attack of instruments sound more precise than the LCD2 - in all my amps - regardless of amplification and dac. I'm confident to say, the HD800 is no more articulate than the 80 dollar Fostex T50 RP.