There is, the problem is how to know the specific sound as it was recorded. For example, if you really want to know what Nightwish's Century Child and Once sound like, you'd have to have Rotel and B&W in an acoustically treated room, to get close to what "consumer" set-up they have in Abbey Road, or Genelecs for studio monitors which is what they used for the succeeding albums (not sure if they also used these in Abbey Road, ditto the previous albums). Unlike classical music, concerts won't be a good indicator because it's not like they perform in the same acoustically good venues. If you're listening to Lil Jon, then your windshield shattering can be considered high-fidelity "just as the artist intended" (Diamond Audio's marketing blurb can be applicable to Audiobahn and Kicker too, it depends on what you're listening to anyway).
A balanced sound - in terms of measurements* and overall impression - therefore ensures that you're at the safest bet in being close to how how that music was recorded. While I personally prefer this on my set-ups though, if more particular tastes are concerned, I prefer for example using Grados on jazz than rock. It makes jazz sound a bit more raw and live, kind of like being front row and "right there" in a great way,** even my Dad borrows my brother's SR80i. By contrast rock music with a lot of instruments in it sound like they're all over the place and yet nowhere on the Prestige series.
*Source and amp are easier to measure, but they also need to be really flat, and the amp's impedance, current+voltage output, and distortion at your listening levels have to match the headphone's impedance and sensitivity.
**Kinda like this: http://i.imgur.com/63fal.jpg
Originally Posted by Spyro
....a more U or V shaped presentation seems to make the presentation more expansive and bigger.
"Seems" is the keyword here. A strong midrange tends to present a soundstage with the shape of a V, with the pointy end the vocalist in front of you, and that's why a lot of people like that. Increasing the treble makes the soundstage seem bigger because you get to hear more where, for example, the cymbals are, but soundstage size isn't the same as imaging accuracy. I'm not sure how your set-up actually is, but as an example, I tried out my gear with some home audio CDPs and the soundstage is much larger, but not necessarily correct - bass drum in front of the vocals, drum rolls around me like 3D, but it gets old quickly because if I visualize that it's like Mr. Fantastic playing drums far out around the band, which of course isn't "hi-fi" given there's no such human with Reed Richards' abilities.
For speakers at home though I really loved my Pacific Pi10's, not just for the balanced sound but also the swivel mounts on the tweeters. I can give them nearly double the toe-in of the midbass to control higher frquencies while maintaining width - female vocals aren't as far out forward and I don't get the "Mr. Fantastic playing cymbals mounted in front of the guitarists"-effect. And this isn't just the room - some reasonably well-treated dealer showrooms still do that Mr. Fantastic out of place percussion imaging thing, or as with some speakers, a Sentinel-sized drummer instead of Mr. Fantastic.
Originally Posted by Spyro
Can't be all that hard to do....
Actually it is. A dynamic driver is the best example for this. It needs to be large in order to play lower frequencies at a certain distance,* but as it gets larger top end response begins to dip, and a larger driver may not be able to travel quickly on excursion (that pumping movement dynamic drivers do) or for the cone to stay rigid. Making it more rigid makes it heavier, making it slower and affecting PRAT, or making it more expensive. On speakers, the solution was to use specialized drivers, but these come with its own problem: passive crossovers can affect the sound too, and multiple drivers even with a good passive crossover can end up with a complex impedance load that in turn affects the signal going into it, requiring high-current, high power amps (those triple bass driver towers with the midrange and tweeter? For get about using an older, $299 MSRP entry-level receiver on those - chances are current $199 might actually be better). Active crossover set-ups aren't that easy to sell (much less set-up unless you're selling to pros, or amateur but well-informed car audio enthusiasts) - mass market this and many will be too lazy to set it up right, or destroy their equipment.
Cabinet and chassis design matter too. Acoustic issues related to dampening is one big problem - that's why big and bulky speakers are more expensive, because the enclosures take up more material and man-hours (and they'd invest on the finish if they'd go that far anyway, and you'd have to ship that. Some speaker kits come like Ikea furniture - thick MDF panels and you have to assemble them - but of course don't expect them to look like Duevel Jupiters when you're done (unless you just buy the drivers and build the enclosure from scratch). On headphones, the most popular example of this is how many people replace the plastic chambers on Grados. And then there's port design on speakers (also IEMs) - do it wrong and you end up with a speaker that reaches low but can't articulate individual notes, or worse, distorts on excursion.
"Fullrange" drivers aren't all they're cracked up to be either. On speakers, even Fostex drivers need a little help - you either add supertweeter to take over above 12khz, or use a filter crossover on the drivers that have peaks or get louder above a certain point, just ot bring all that down (still not fully getting 20hz to 20khz and flat).
Then finally there's the environment between you and the drivers - the room acoustics and toe-in, the earpads' and the eartips' fit and location of the drivers/port relative to your ear drum, etc. If you really want to measure a system at the headphone output, you have to use a ballistic dummy head built around and in an actual skull, with a molded ear canal leading to the measuring microphones (on whether you can fit two good quality mics inside an adult human head, I wouldn't really know).
*whether it's on an earcup by your ears, on a desk 1m away, or in a room 2m away from you and 0.5 away from the nearest wall
Originally Posted by bigshot
Assuming proper engineering, a balanced response makes everything sound good.
Just to add, think of balanced systems as good quality steak for a price point, then grilled (over coal or a brick, wood-fired oven) or cast-iron pan seared seasoned with just the bare essentials, like salt, pepper and maybe butter on the first done side. Personal preferences on genre-specific matching of headphones and speakers is when you use a specific glaze (truffle, teriyaki, PFChang's Chinese 5-spice NY Strip, etc) or sauce (pepper-liquor fillet steak gravy/au pois, garlic+mushroom gravy, etc).