Those surround sound headphones are a nice way to add $50 to a headphone with a $2 line joint.
Headphones with the surround sound, are made to only work with the plug in or equipment they come with. This mean if you don't use the surround sound thingy, the headphones are missing a component.
The reason they aren't used, is because audio only headphones don't need them, they already have them.
Simply saying, your headphones are stripped down to make you believe the SURROUND SOUND COMPONENT is worth more money.
Look into marketing, this is the way companies make you buy this, when other companies have the same.
Listening to my Grados, with a echo set into the eq, it sounds as if the SURROUND SOUND is on. The component you have or bought with your headphones probably set the sound late in certain sections making it possible to feel as if the sound is all around you.
Simply, there is no way that a Stereo headset can broadcast four of six different sound patterns in different directions (like surround sound)
Yes, there is headphones with multiple drivers in them, yet they play different sections of the audio pattern to try to separate the audio waves to make the audio feel more define.
Think of surround sound as a set speaker around the room. each speaker plays different sounds from the source in different areas. (explosions behind the camera, come from behind you) A stereo plug can only conduct two sound patterns.
Your surround sound, is just a echo created an probably some other effects.
Hope my, over detailed writing works