I've tried various ways to straighten up the cable, including keeping the cable in boiling water and straightening it, baking the cable in oven, it will never fully straighten. I'd suggest you don't even try. Waste of time and a cable, that you might use sometime in the future (because the cable...

http://www.custom-cable.co.uk/sennheiser-replacement-lead-for-pxc450-3m.html   I'm pretty sure this cable should work great. The headphones-side with 2,5mm jack looks exackly like HD-380's. It's straight. Just what one would look for HD-380   It doesn't fit HD380 Pro. It includes mic...