I am a sound tech for a local concert venue, so I have some expertise here. ALL, and I do mean ALL speakers don't necessarily need to be "broken in" per se, but when new the cones are quite stiff, and sound quality/character depends on the flexing of the cones. This is part of the reason why vintage guitar amps are so incredibly popular, not only are the speaker cones of superb quality, but over time and use the cones develop, sort of a sweet spot.... then of course they get so old and used they start to lose sound quality, but I digress. It'd be a good idea to let the speakers break in a bit when new, just to get the initial stifness worked out, no big deal at really though, most time it wont make a bit of differance, but better safe than sorry. The noyl way i'd worry about it is if you take them out of the box and immediatly crank them to high hell, you might just blow the cone, who knows. It's just like with guitar amps, most manufacturers recommend playing a bit at low levels on a new amp, and for the very same reason. But as I said, it's not some huge deal either way.