Yes this thread is way old, but I just tried these plugins (dolbyhph.dll and foo_dsp_dolbyhp.dll) with foobar2000 1.1.6 and they work *GREAT*.
I may post more detailed reactions after I've listened to more music, but all I can say right now is this is the best experience I've ever had with headphones, or for that matter a stereo, since 1974. Using the chain "convert stereo to 4 channels -> Dolby Headphones" has taken what I'm hearing (Future Sonics Atrio with the MG7 driver coming out of my basic Toshiba Satellite laptop) to, well, not just a new level, but seriously the best sound I've ever had. And I've gone through a long list of stuff looking for a special sound - speakers ranging from B&W 801f original series to Klipschorns to big VMPS towers and just about everything in between, headphones including AKG K240 and K340, Sennheiser 414, 424 and 600, Beyer Dynamics, Klipsch S4 and X10, Monster Turbine Pro Coppers, EarSonics SM3 and now the Atrios.
This is freaking awesome.
Thanks to OP for starting this thread so many years ago.