They are more accurate than most people think..thats why they are/were popular.
They are very fussy also in what you are feeding them from..so if you use a cheap amp it will show it's short comings big time, if you drive them loud the sound is awful for a few reasons (Thermal Compression being one) and also yes the top and can be a little piercing.
But the drivers are very unique not cos they are white by the way lol...and also the sealed box design gives them a VERY good time domain performance..bare in mind the human ear is more sensitive to this than it is to frequency response.
I find it very misleading that so many people seem to perpetuate the aphorism: "If it sounds good on NS10s then it will sound good anywhere."
Like most claims of this type, the key missing ingredient is the context.
You are quite right, in that a good mix will sound good anywhere -- by definition.
The point about the NS10s (and some other sealed cabinet speakers, as well as a few other specific speaker designs) is that they are very revealing of certain aspects of a mix that most ported speakers can't reveal, and even obscure.
Mixes can sound good on ported speakers sometime simply because the largely inherent LF resonances mask completely some fundamental problem with the bass end timing or the the balance and EQ of bass instrumetns.
Most people can create a reasonable mix on any speaker once they're used to it, but a mix created on an NS10 (and a few others) will certainly not suffer from some of the masked problems that can so easily slip by on other ported speakers. And therefore those who understand this important feature are probably quite correct in their claim that "if it sounds good on NS10s then it will sound good anywhere". At least from the point of view of bass instrument timing and balance.
This is a very interesting read:
http://www.soundonsound.com/sos/sep08/a ... hans10.htmAlso a modern NS-10M would be the Acoustic Energy AE-22 which is not available in the US unfortunately, this every one says is what NS-10 owners wish their Yamaha's sounded like lol they are great monitors