Why are they still hanging around in some setups despite being considered outdated? To understand that, we need to go back to ...

Ideal for connecting subwoofer speakers to audio components ... resistant gold-plated RCA connectors provide a consistently tighter fit than commonly rolled cables with wider tolerances.

A plug and socket for coaxial cable. RCA connectors are used for analog audio signals (see analog audio). They are also used for digital audio (see S/PDIF) and analog video (see composite video).

As surprising as it may be, RCA cables still have their place in modern home entertainment systems and even professional ...