Now for part 2 in our continuing series on cables and connectors.
RCA: The same physical cable used for video, the RCA audio cable carries one channel of analog audio. For every channel of surround sound, you need a separate RCA cable. So, 5.1 surround sound will require six RCA cables. They can be susceptible to interference. Typically, the left channel is color coded white or black while the right channel is color coded red. Yes, it’s worth it to buy a higher quality RCA cable and avoid the flimsy budget one.
S/PDIF stands for Sony Philips Digital Interconnect Format. It’s a digital format that can be carried over an optical cable (TOSLINK) or a coax cable with RCA connectors. There is no difference in the actual information carried in either type of cable. The optical cable is immune to electro-magnetic interference but cannot be bent at hard angles. The RCA cables are usually color coded orange. S/PDIF was a step forward since it combined multiple audio channels into one cable. However, audio formats such as Dolby TrueHD and DTS Master Audio do not work with S/PDIF. Blu-ray players land up downgrading the signal into Dolby Digital. Click here to learn what you missing out on if you do this. This has more to do with incompatiblities around copy protection than it does with bandwidth. As a result, you need to either go back to RCA cables or use HDMI when outputting lossless audio.
HDMI: See Part I
While I was able to rank video cables from best to worse, it’s not as applicable with audio cables. Use what works best for your situation. For example, I connect my TiVo Series3 to my receiver with an optical TOSLINK cable. Since Dolby Digital is the best audio it can output, I am not losing any sound quality. It also saves me from running lots of RCA cables. Ideally, I would use HDMI, but my receiver can’t take HDMI. This forces me to use lots of RCA audio cables to connect my blu-ray player to my receiver. Ironically, it will all be wireless one day which will make this post obsolete.