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AVS › AVS Forum › Audio › Subwoofers, Bass, and Transducers › Help with long subwoofer cable noise.
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Help with long subwoofer cable noise.

post #1 of 7
Thread Starter 

I have a definitive tech supercube 2000, and am running a cable from my pioneer elite receiver to the sub through 1' conduit tubing that i put in the walls and ceiling. Unfortunately the distance is nearly 50 feet when all said and done, so i purchased a (what i thought was) good shielded cable. After a while i'd notice a static clicking noise that will build up.. and then dissipate.. this was happening daily. I called definitive and they suggested running the sub with a shorter line to rule out the sub as being the problem. So i've done that and the noise is gone. So the problem is obviously something related to the 50' cable.. either interference in the wall/ceiling (it does cross over some power lines - but again.. this is a shielded cable inside a conduit tube). So my question is..  should i try a different 'higher quality' cable? is there such a thing? i've posted the full spec of the cable i'm using below (from monoprice.com) . Any guidance would be GREATLY appreciated! thanks.

 

 

 
50ft High-quality Coaxial Audio/Video RCA CL2 Rated Cable - RG6/U 75ohm (for S/PDIF, Digital Coax, Subwoofer & Composite Video)
 
This cable is used to connect DVD players to audio receivers, satellite boxes and cable boxes to audio receivers, computer audio equipment, or any other equipment that supports digital coaxial (S/PDIF) interface interconnect. It can also be used as a subwoofer cable and will provide excellent signal quality with minimal degradation for your high powered home theater subwoofer.
 
This cable allows jitter-free transfer of digital audio signals. The low-loss cable design includes a pure copper center conductor and shielding to preserve signal strength and minimize noise. Gold-plated RCA connectors and pins provide solid corrosion-free contact.
 
Features:
 
- Connectors: Single RCA plug (male) to single RCA plug (male).
- 24k gold plated 8-cut connectors ensure long-lasting corrosion-free connections.
- Fully molded connectors provide excellent strain relief.
- High-quality coaxial wire with copper braid shield reduces unwanted noise and distortion.
- Gold-plated RCA connectors give you solid corrosion-free contact.
- Easy installation with non slip rubber grip.
- Improves digital signal delivery as compared to standard RCA type audio cables.
- True digital signal maintained by high quality materials and connectors.
- 99.999% pure oxygen-free copper conductor.
- High-density double shielding for maximum rejection of EMI and RFI.
- Capacitance: 22PF per foot.
post #2 of 7
Quote:
Originally Posted by astrogeeker View Post

should i try a different 'higher quality' cable? is there such a thing?
There isn't. I've never heard of these noises myself, not even with 100 foot interconnects.
post #3 of 7
Cut the ends and re-terminate. I'm betting there is a tiny strand of wire shorting at one of the ends. If they are prefab cables, you probably can't see what's going on in the ends without cutting them off. Much like Mr. Fitzmaurice, I've never seen a similar problem with runs even longer than what you have.
post #4 of 7
Thread Starter 

CRAP! well i just purchased a newer/better cable (and much more expensive) and am getting the same crackling noise with the new 50' cable... even when its lying on the carpet! soo.. to recap:

 

good 50' cable in conduit tube in wall/ceiling = problem

good 5' cable on floor = no problem

better 50' cable on floor = problem

 

the sound sounds like a gieger counter noise.. starting with rapid crackles.. and tapering off over the course of a minute or so.

 

so what does this mean? its the sub? would a problem with the sub exhibit itself only with a longer cable?

 

need some help here guys!

 

thanks

post #5 of 7
Quote:
Originally Posted by astrogeeker View Post

After a while i'd notice a static clicking noise that will build up.. and then dissipate.. this was happening daily. I called definitive and they suggested running the sub with a shorter line to rule out the sub as being the problem. So i've done that and the noise is gone.

The problem sounds reasonably intermittent. How extensively have you tested your setup with the shorter cable? There's always a chance something else could be going on, especially since you've tried two different cables now.

I wonder if some of these might be a benefit in this circumstance on the long cable(s)?
post #6 of 7
Since you are having the same problem with both cables, go back, look at the instructions for mounting the cable ends, and be absolutely certain they are installed correctly.

Bill C
post #7 of 7
For a long sub-woofer co-ax interconnect cable run, the "Blue Jeans Cable LC-1 Analog Audio Cable" is the first choice. It's very well shielded and the end to end resistance is very, very low which is important in longer cables.
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