QuestionYes, I seem to be getting an AM radio channel. I hear music and talking...When using a 12 foot cable, the sound is a bit lower...but still there. So...if the cable is short, I am sure that there will not be a noticable sound. Unfortunately, I do not have much space in front, that is why I have my sub in the rear. Worse case, I can get a really short cable and put it in front of my fireplace...
Another question, will grounding the Subwoofer itself or using a Monster Power Center work?
Thanks...
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Followup To
Question -
I have a 24 foot Monster M series 550 cable going to my powered subwoofer. I can hear music coming from my sub. I unplugged the cable from my receiver and I still hear the radio. I unplug the cable from my sub, and the sound is gone. The cable seems to be acting as an antenna. I tried ferrite beads and was unsuccessful (unless I was using the wrong ones). Is there something that I can do?
Thanks...
Answer -
By "music" you mean it's always a radio channel?
Hmm... this is not uncommon but there can be any number of wild things going on - induction, ground loops, etc.
You'd be surprised how often I wrestle with this, especially when Co-ax cable is involved.
We prevent it in the Pro-audio world by using "balanced audio", my entire house is wired up this way.
Frankly, it's a miracle it doesn't happen more often in the house-hold with consumer audio, no matter how "good" a monster cable you use, you're still stuck with a RCA conector and only two conductors, neither one of which is truly grounded.
It's likely that your cable is acting as its own diode antenna. The "Sheild", or outer conductor, is the most likely culprit. Since this is an integral part of your signal path, you can't just send it to ground or filter it. Essentially those monster cables with a fat dielectric and a large braided exterior are great for carrying signals, even ones you don't want -A frustrating lesson in the photoelectric effect.
Does it still happen if you plug the sub in using a short (6' or less) standard RCA cable? If so, and you can, move the sub closer.
If you don't want to move your sub and you are handy enough to solder your own cables, I would find a two-conducter twisted cable (18 AWG or bigger if you are a "Gauge-weenie) - sheilded if you want to be extra cautious, just don't connect the sheild to anything - and make yourself a new 24-foot cable. You could even use some old Twin-ax off ebay. Here's an example of the kind of wire I'm talking about:
-West Penn 293-
http://www.westpenn-cdt.com/pdfs/CommunicationCablesNonPlenum.pdf
This is definately the best option.
I would bet over the years that I've saved bundles making my own cables, those Monster guys are robbing consumers.
Otherwise, you can look for a pre-made RCA cable where the two conductors are twisted or at the very least seperated and running parrallel (as oposed to coaxially - one wrapped around with the other tunneling through).
I might try Mogami, Hosa, Comprehensive, West Penn, Belden, BlackBox, KnuKonceptz, Lightning Audio... all the usual left-of-center folks.
AnswerUnfortunately, no.
Or atleast 99.9% unlikely. This is a text-book symptom of a common low-field photoelectric effect being picked up on the outer conducter of a co-ax cable.
There are some very rare 1-in-a-million conditions with ground loops that might do this, but not if the radio effect stops when you unplug the cable or make it shorter.
If you don't want to move the sub see my recommendations above. I don't personally use RCA connectors much, so I'm not sure if they make them long enough, but I do know that Lightning Audio makes shielded twisted-conductor-pair RCA patches called the LBIC series.
