Wiktionary
n. 1 (context sound English) The process of blending the left and right channels of a stereo recording. 2 (context aviation English) The supplying of one fuel tank of an aircraft with fuel from the other.
Wikipedia
Crossfeed is the process of blending the left and right channels of a stereo audio recording. It is generally used to reduce the extreme channel separation often featured in early stereo recordings (e.g., where instruments are panned entirely on one side or the other), or to make audio played through headphones sound more natural, as when listening to a pair of external speakers.
Crossfeed is claimed to provide relief for a small fraction of listeners who otherwise complain of "fatigue" and headaches when they listen to stereo recordings.
Crossfeed is most commonly found in headphone amplifiers and often can be toggled with a switch. Many audio player programs for computers can perform crossfeed via plug-ins or built-in processing.
Usage examples of "crossfeed".
I shut down the air-conditioning and closed the outflow valves on the panel, set up the fuel and opened the crossfeeds, then I went back and double-checked the aft entry door closed, and made sure the cargo net around Linda's stuff was still secure, and replaced the emergency exit hatch.