RG-6 to sub question (1 Viewer)

[Keir H]

I've notice alot of people rec'd RG-6 for subwoofer use. I'm wondering if anyone has noticed a improvement or otherwise in comparision to say a Monster THX cable. What else do I need to connect the preamp and sub up together? Will a long run (30ft) reduce sound quality ? thanks everyone!

 

[Bob McElfresh]

I was using a 25' RG6 CATV coax for my SVS when it first arrived so I could put it in the far-corner. Total cost for cable, connectors and RCA plugs was sub $12.
I have relocated the sub to the corner behind my rack so I am using a left-over 6' Monster video 2 cable because it fits better.
There is a slight change in sound, but I am told this has a lot to do with sub-placement, not cable brand/price.
And I admit that I probably could not hear much difference. (Human hearing is most sensitive in the upper-mid range, around 12 khz. This is FAR away from the below 120 hz for a sub).
The guys at SVS (who build subs for a living) recommend using inexpensive interconnects for their subs. They have done lots of tests on subs so I expect they have also tried different cables. They also have some PC-based RTA systems so they can fire off a test, change a cable and re-test and see (not hear) if there is a difference.
The rule-of-thumb I have always followed is that a cable is limited by it's upper band-width. And you want the cable to have a bandwidth that is roughly twice the highest frequency signal you try to send down it.
So this means:
- a cable that works fine for audio (0-20,000 hz) will work fine for a subwoofer cable (0-120 hz).
- a cable that works fine for RF frequencies (like your CATV coax in the Khz range) can also handle audio and subwoofer frequencies.
- a cable that works fine for video frequencies ( High Khz, low Mhz) will also work fine for RF, Audio, subwoofer frequencies.
- a cable that works fine for HD/Progressive video (Mid Mhz) will also work fine for video, RF, Audio and subwoofer.
We had a debate a few months back about which was better:
A) Long interconnect to an amp, short speaker wires to the sub.
B) Short interconnect to a amp, long speaker wires to the sub.
And we decided that option A was the better way to go. I think this was because we decided that sending a low-power signal along a long cable was cleaner/had less problems than trying to shove WATTS of power along the same length speaker wire.
So my advice: get some bulk RG6 CATV coax and RCA connectors and make your 30' cable to the amp, then 12 ga speaker wire a short distance to the sub.
Later: You can buy some bulk Canare RG6, high-bandwidth coax cable and the nice Canare connectors and do your own A/B comparison.
Both of these will cost you lots less than a that single Monsert THX cable.

 

[Keir H]

I give you much praise for such a great informative reply Bob! Thanks a bunch again. It makes sense. I was starting to wonder if indeed spending $50 or more on an sub cable worth doing. I think your mind will play tricks on you and make you believe that spending more would get you better sound from your sub. Glad I got educated advice on this question. So now I won't feel like I was being cheap. : )