It is not possible to listen to lossless multichannel( SACD, DVD-Audio, Dolby TrueHD, DTS- HD MasterAudio, or multichannel PCM ) as recorded over headphones. The JVC processor( and AKG used to also have a processor ) will simulate multichannel on headphones, given a lossy 5.1 Dolby Digital or DTS source. I had the AKG system( which also required special AKG headphones ) but it never worked for me.
That said, I will now contradict myself. There is a processor available that is claimed to allow you to listen to surround music or soundtracks over headphones, in their full 5.1 or 7.1 glory. It is the Smyth Research Realizer A8. It is expensive( [size=x-small]$3,360.00 USD, which includes a pair of Stax phones )[/size]. It will only work if you already have a 5.1 or 7.1 setup and want to duplicate the sound of that system over phones; it uses a microphone to calibrate the headphone processor to replicate the sound of your speakers in your room over the phones. Unlike binaural, it has motion detectors, so that turning your head will not cause the sound field to shift with your head. Widescreen Review gave it a rave. Go to www.smyth-research.com to find out more.
The problem with the JVC and Sony processors is that they have to 'fake' multi-channel over 2 channel headphones, so they cannot be lossless. I have Dolby Headphone in my receiver and I watch 5.1 HDTV with it. It only works for me sometimes, and how well it works it depends on the source material. But even when it works, it isn't anywhere near the surround effect you get with 5.1 speakers.
The Smyth Research processor doesn't fake it. It attempts to replicate the pressure vectors at your ears by using a mic and test signals to calibrate the processor for your particular speakers, listening position and room. I have not heard it but only read about it. See www.smyth-research.com for more.