5m to reach anywhere you put your sub woofer. Put your subwoofer under your couch! In your cabinet/in the wall/behind the couch. Because low frequency effects (the sounds sub woofers make) are not direction you can get away with putting your sub anywhere creative/anywhere you like (unlike the other 5speakers in a 5.1 system). In a 5.1 system the .1 refers to the subwoofer. If you have a 5.2/6.2 or 7.2 system than this means you have two subwoofers in that surround system. Subs had a distinct difference (add bass) to surround sound. Whether it be active or non active subwoofers. These cables are used with ACTIVE subwoofers (sub-woofers with a power cord) Any further questions on home theatre - email us!