I need new sound card with Dolby Headphone or CMSS-3D for my ATH-AD700. My system is Windows 7 64-bit.
All the best!
I would have suggested a $40-50 X-Fi Titanium (non-HD) from Newegg, but they've stopped selling them there.
You might have some luck on eBay getting one for that price, though.
If you intend on upgrading headphones down the road and can stretch your budget to $100-120 or so, there's the X-Fi Titanium HD.