There's many reports of the Spirit Pros cracking under normal use. Focal claims it's just the first few batches but recent purchasers have also reported cracking.
My tentative hypothesis is that headphone manufacturers know us audiophiles are suckers and will pony up big bucks if something sounds good, even if it doesn't last. So there's little incentive for them to invest in R&D on product durability and invest in more expensive materials for greater durability. In other words, the competition at the higher end levels is 99% on sound quality.
Not necessarily that they are trying to dupe people, but maybe they really didn't have any idea about the behavior of the plastic composition they chose for it. Maybe it was tough enough for their lab tests, then maybe somebody used them in a place with different atmospheric conditions than that lab. Or what is likely is the factory that made the headphones or parts of them might have screwed up - it could have let impurities contaminate the plastic, for example.
NAD for example is fairly new and small if I remember correctly. Other companies are quite obviously larger, like Sennheiser for example. All of my Sennheiser headphones are very well built so it could just be a company size and resource issue. I believe Beyerdynamic headphones are very well built as well.
Define "fairly new and small," because this came out in the 1980s...
...and they have a larger distributor network since they've been around long before direct-selling on the internet driven by review samples for forum members/admins (and 30-day money back home trial guarantees). Just because they're called "
New Acoustic
Dimension" doesn't mean the company itself is still new.
If anything, they're new with just headphones, but one can't blame those who expect a lot more from them considering big companies if they put their minds and cheques into a project and didn't meddle with the engineers, they can beat smaller, more specialized companies. For example, there's the GT40 beating Ferrari in the late 60's; and when was the last time that it wasn't an Audi (or Bentley, owned by Audi, using an Audi with a roof) that won Le Mans?
Of course that statement would mean something if we go way back before NAD and many other British brands, because...well, guess why the largest companies that specialize in headphones and microphones are German(ic).
They lost the war, their military effectively dismantled, and nobody wanted to go along with Churchill's "Operation Unthinkable" (which is basically to
rearm all central Europe under Allied control for a unified capitalist do-over of Operation Barbarossa), so those engineers and companies had to look for civilian applications instead of subsisting on juicy government contracts supplying the Wermacht, Luftwaffe, and Kriegsmarine.
To be honest, Sennheiser is one of the worst companies in this, because not only do most of their headphones both
feel breakable and
are breakable, a couple of them (HD600, HD650) feel pretty well put-together but in fact
aren't -- so you'll be less inclined to be careful with them and you'll end up with this:
Sennheiser used Europlastic for the HD600/650's headband. It's a dense, extremely brittle plastic. Normally flexing the headband to put the headphones on can do this; this was not from abuse of any kind and I have seen this happen on numerous occasions.
I'm a 7.5 on hat size (if that's a good enough indicator of my head size), and with the adjustment on the headband at seven clicks out from the tightest position, I barely bend the headband when putting them on or off (at five clicks or less the bass isn't as I like it). When I do take them off though they bend my earlobes going out. I have more complaints about the finish actually - that paint flakes too easily on the headband, likely due to however little flexing it does. I'm just using this as an excuse to, at some point, paint my HD600 in the same color as the HD580J. I don't hate the marble blue on its own but with it flaking anyway I might as well get it in the color I prefer.