Jack is an incredibly flexible piece of software for making audio connections. It’s mostly used to connect and patch virtually within one computer but it has a range of amazing extra features for connecting things in alternative ways. This is exploited to it’s fullest in the zita-njbridge package. To quote from the manual on zita-njbridge: The zita-j2n (sender) and zita-n2j (receiver) applications allow to exchange up to 64 channels of full-quality uncompressed audio streams between two or more systems running the Jack audio server.