How important is EMI and RFI rejection?

Well I'm confused....

I asked this question because somebody on another forum said NBS cables were all about EMI and RFI rejection....I use NBS and like them....

After seeing the responses so far....I found this on the NBS website...

"Noise, in a cable, can and will affect the audio frequency range and interfere with an audio signal. The most common noise, Radio Frequency Interference (RFI), affects a cable directly in the audio range. RFI presents itself as hiss, commercial radio broadcasts, intercom broadcasts, or any other radio signal broadcast in the audible range.

Another source of noise is Electromagnetic Interference (EMI). Whenever electricity, i.e., an audio signal, passes through a wire, it produces inductance that creates an electromagnetic field. Because EMI manifests itself at a high frequency, it is commonly believed not to interfere with the audible range of frequencies. However, all frequencies demonstrate harmonic structures. Even if the cause of EMI is outside the audible range, the upper and lower harmonics of a given frequency often present themselves within the audible range. At the very least, EMI causes degradation of audio frequencies."

http://www.nbscables.com/info/why.html

So I guess it still open....

NBS definitions of EMI and RFI are wrong. Clearly RFI is due to Radio Frequencies Interference which we cannot hear. EMI does come from inductive coupling, as I also said, which is most likely 60 cycle hum in the US, and you can hear it.

Perhaps NBS is jumping to the symptoms - you can hear the modulated signal from RFI related problems. This is called rectification. No idea regarding their EMI description?!

Based on 40 years of working with radios and audio I know the descriptions and remedies listed at Blue Jeans Cables are correct...

http://www.bluejeanscable.com/articles/humrejection.htm

...as are my recommendations for remedying them with your existing cables above.

This doesn't mean NBS cables are bad (I've never heard them or Blue Jeans cables for that matter), but you really have to separate technical from marketing.

If you like NBS cables and you have no EMI or RFI problems, then that's great. If you do, you should check out BJC and/or employ my remedies above as both solutions are very inexpensive (some even free :)

Dan

I have no problems with NBS. I have recently tried other brands and while having excellant sonic qualities....their "blackness" were not equal to my NBS. Since the NBS were said to have these rejection qualities...I was wondering what cables excell in EMI & RFI rejection. Or maybe I should just ask what cable brands have the blackest background?

Not sure there is a technical measurement for blackness :) I was just responding to the original question and when I see stuff like: "Radio Frequency Interference (RFI), affects a cable directly in the audio range" it's just flat out wrong.

I've been looking for some new cables and liked the design philosophy of BJC for unbalanced audio cables. Why? Because their audio cables are based on video cable stock. Therefore, you know they have the best possible RFI rejection as this is a primary design criteria for delivering radio frequencies. Do they sound good? I have no idea. But I'm am confident they provide extremely high RFI rejection as all high quality video cable will.

Good luck w/your search.

In my limited experience, the JPS brand of cables provide for the darkest, most eerily silent background. I have tried their Superconductor+ and Superconductor 3.

Kenobi