Need advice on subwoofer cables

[Speedskater]

Henry Ott, industrial EMI/RFI consultant writes:

Unbalanced Interface Cables
..............., we can conclude that for the case of an unbalanced interface, the only property of the cable that has any significant effect on the common impedance noise coupling is the shield resistance.

http://www.hottconsultants.com/pdf_files/Audio Interconnections.pdf

 

[BoredSysAdmin]

Bill Whitlock writes about common impedance coupling noise:

Leakage Current Effect - A Calculated Example
•A 25-foot cable (foil shield, #26 AWG drain wire) has an end-to-end shield resistance of 1Ω
•Measured leakage current between the ungrounded devices is 316μA (well under the UL limit of 750 μA)
•From Ohm’s law, noise voltage E = I x R = 316 μA x 1Ω= 316 μV
•Consumer−10 dBV reference level = 316 mV
•Signal to Noise ratio = 20 x log (316 mV⁄316 μV) =60 dB
•This is 35 dB worse than an audio CD!
•Same length of Belden #8241F cable, with its shield resistance of only 0.065Ω,
makes S⁄N 84 dB, an improvement of 24 dB!

Interesting theoretical example, but a) Coax cables have braided allum or copper shield, not foil shielding.
Consumer refernce level voltage is 1.5v
https://www.honeywellcable.com/CatalogDocuments/RG59-BC-Shield-vs-CCA-Shield.pdf
http://www.pacificcabling.com/Information/Information_other/CCTV_cable_choice.htm
https://www.pasternack.com/images/ProductPDF/PE-B305.pdf
https://www.cableorganizer.com/coaxial-cables/rg59-coaxial_pvc-plenum.html

 

[BoredSysAdmin]

Bottom line, BJC is not much more expensive and if OP wants a cheap "warranty" - then by all means he could/should get BJC coax cables (they are of course using belden wires)
My point is relevantly small runs such as 50ft practically any coax rg59/u 75 ohm cable will do just fine.

 

[Speedskater]

Interesting theoretical example, but a) Coax cables have braided allum or copper shield, not foil shielding.
Consumer refernce level voltage is 1.5v
....................................................

First we must not confuse base-band video coax with near 1 GHz cable TV channel coax.
All the cable TV coax that I am familiar with has a Copper Clad Steel (CCS) core a aluminum foil shield and a few token strands of aluminum braid.

 

[BoredSysAdmin]

First we must not confuse base-band video coax with near 1 GHz cable TV channel coax.
All the cable TV coax that I am familiar with has a Copper Clad Steel (CCS) core a aluminum foil shield and a few token strands of aluminum braid.

This is a different cable, I was talking specifically about rg59/u, these used for subwoofers, digital audio and CCTV applications

 

[Speedskater]

Yes we are thinking of very different coax cables. But which 'RG-59/U Type' specifically? My Belden catalog lists 19 different 'RG-59/U Type' Standard Analog Video Cables (and that's just in the video section). With specs all over the place. With shield resistances from 2.6 to 17 Ohms per M. That's over a 16 dB difference.

 

[Tankman]

You don't have to spend much over 25 to 50 bucks on sub cables anything much over that would be a waste. Check out Monoprice, even Amazon sub cables are good quality cables can be had for not alot of money. Depending on how long your run is 15 bucks..

 

[Speedskater]

In the past Monoprice was a good source for low budget cables. But now with their new products, they seem to have gone over to the dark side.

The Blue Jeans Cable LC-1 remains at the sweet spot in price and quality.

 

[Tankman]

In the past Monoprice was a good source for low budget cables. But now with their new products, they seem to have gone over to the dark side.

The Blue Jeans Cable LC-1 remains at the sweet spot in price and quality.

Only mention Monoprice Only cause it came first to top...but Yes lots of alternatives for not a lot of money...

 

[mtrycrafts]

You also need to consider how it will be installed. In wall into a terminal box at each location into an RCA jack out or the terminated cable with RCA jack out at end points without termination in a box in the wall.
Pre terminated cable but terminated in wall box may need to be thought what kind of box to use. You cannot bend a terminated cable in a normal electrical type box in the wall.