Quick Summary Topping has added crossfeed processing to its DX5 II DAC to process audio and make headphone listening sound closer to stereo speakers. The update is free, while the DX5 II costs around £300. Topping has given its high-spec DX5 II DAC and app an interesting free upgrade – and it's designed to make your headphones sound less like headphones. (Image credit: Topping DX5 II)Topping DX5II headphone crossfeed: how does it work? There's also a second, simpler crossfeed mode that adds a bit of speaker while "maintaining more of the typical characteristics of headphone listening".