Originally Posted by SilverEars
Explanation would be super. Thanks.
IEMs and headphones cannot have proper soundstage, practically by definition.
Music is designed for speakers, not IEMs. With speakers, a sound from the right reaches your right ear first, then it hits your left ear a bit later and quieter. Your brain uses this to tell that the sound should be coming from the right, at a particular angle.
IEM's can't do this normally because the left and right sides are fairly isolated.
A crossfeed DSP is a bit of software that tries to simulate speakers, by basically taking one side, delaying it a bit, making it a bit quieter, and then feeding it to the other side (and vice versa). You can get plugins for most music software, or find an app that supports this feature.
Another thing you can do to change soundstage is to use an equalizer. Your outer ear amplifies different frequencies depending on whether the sound is coming from above, behind, left, right, etc. So adding dips or peaks to specific frequencies above 1 kHz can make huge changes to soundstage. This depends on your ears, though, so you need to experiment.