Differences Between Beyerdynamic Pro and non-Pro?

Can anyone clearly explain the difference between the "Pro" and "non-Pro" versions of Beyerdynamic headphones, specifically the 880 and 990? Over the past month I have upgraded my system with an Angstrom 100 (DAC only) and a Vincent KHV-111MK headphone amplifier. In concert with existing Sennheiser HD-580's, the sound is quite satisfying. I'm considering purchasing either the Beyerdynamics or Sennheiser HD-600's. A subsequent thread might question how it is possible to justify the purchase of headphone cables that are more expensive than the headphones themselves. But, I'm getting ahead of myself...
Somebody asked that on an audio engineering board I frequent. Below is the response they got from Beyer. It also explains the difference between the 250 and 80 ohm which I'm including as it might interest you.

Spending that amount of money on headphone cables is something that doesn't make sense to me. Instead of $300 on headphones and $300 on cable, buy $550 headphones like the Denon AH-D5000.


To your question: What is the difference between DT 770 PRO 250 and 80Ω?

The transducers of the 80Ω versions are stronger and more powerful, a bit more mid accentuated. The 250Ω version sounds more smooth and voluminous. Normally the 80Ω is louder than the 250Ω version.

The DT 770 PRO 80Ω has a straight cable (3m), it is for the usage as studio monitor headphones – especially for instrumentalists.
80Ω systems are ideal for powerful reproducing of low-frequency material f.e. coming from a bass guitar.
The stronger system and thicker membrane provides punchy and clear bass sound at high levels.

The DT 770 PRO 250Ω system with its lighter coils sounds more smooth and analytical. The application in studio would here be more in a mixing situation to analyse the whole mix. The coiled cable in this version is ideal to connect the headphone directly to any mixing desk without having any disturbing cable lying on the floor.

To your question: What is the difference between the PRO and Consumer DT 770 headphones?

All our premium headphones (made in Germany) are available as PRO and Consumer Versions. PRO headphones are conceived for maximum durability even in toughest studio conditions, the Consumer models have the more precious design.

As regards sound, both versions feature equal quality, as they use the same systems. Due to the fact the PRO version uses a stronger headband, this headphone may sound a bit more voluminous and has a slightly tighter fit. Like mentioned above, another difference is that the DT 770 PRO (250Ω Version) features a coiled cable. The Consumer version has got a 3 meters straight cable.