Lengthier cable vs Shorter cable

[flossy]

I just purchased a 18ft Sonicwave bass management subwoofer interconnect cable for my new sub. I really only need a 12ft cable but got the 18ft cause who knows i might end up needing the extra length in the future.

What I wanted to ask from you experts is does running longer cable to my sub over shorter cable have a quality difference? I ran into a couple sites saying that they sell better cable for longer runs without the QUALITY LOSS.

How long is too long, and I guess what I really want to know is will I be ok running the 18ft cable to my sub without having quality issues or is there no difference at all?

Thanks in advance for the help.

 

[markw]

This difference won't degrade perfornamce in any audiable or measuravle way. Actually, a little longer is better since you've got placement optiond.

 

[mokru]

I found a usefull chart on speaker wire loss

I found it while investigating wiring options from Leviton. (They have rca and s-video cable runs that use either Category 5e or 6 computer grade ethernet cabling.)

In http://www.leviton-lin.com/learning/documents/W221_Audio_WP_NOCVR.pdf on page 10 of 12, it gives loss for their brand at certain gauges at certain distances. (I'd venture that other brands aren't too far off the mark.)

Interestingly enough, it validates some of the things I had read on the audioholics educational articles, and I thought the writer might want to inquire with Leviton if he could reprint their findings.

Basically, an 8 ohm speaker loses a half decible over 190 foot run with 14 gauge cable. I'd guess that a good deal of speaker runs are much closer to 75 feet than 190...

While speaker cables are different than rca cables or CATV coax, I'd expect losses to be rather minimal and constant. Proper setup would probably compensate for any of these losses. CATV coax has an incredible bandwidth that will lack any appreciable loss at 12 feet (after all it does carry much higher bandwitdh signals longer without much noticible loss).

 

[Sheep]

I have a 26 foot subwoofer cable. Just in case I want to put my subwoofer behind me.

You'll be fine. The losses are not as bad with subwoofer cables and interconects because they are low voltage.

SheepStar

 

[flossy]

I really appreciate the info, thanks again.

 

[mokru]

If you are concerned about any loss at all.

you can try the run with a CATV coax cable with RCA adapter ends on it and see if you notice any difference. I know that when custom installers do in wall-runs for subs, they typically use CATV coax with F type to RCA adapters on the ends. I've heard subs hooked up this way with atleast 50 feet of an in-wall run without any discernable difference in sub performance.

Also running RCAs as ethernet is supposedly capable of 1000 feet runs without noticeable loss which is 2-3 times the recommended maximum segment length run for a cat 5e ethernet installation. The only drawback is the cost of the adapters and ethernet cabling.

 

[t3031999]

The losses are not as bad with subwoofer cables and interconects because they are low voltage.

While the loss maybe less with low voltage, the real problem is signal interference.

On a speaker-level cable interference of a couple dozen milli-volts doesn't cause any problems at all, but on a line-level (low-voltage) cable the interference is amplified into quite possibly be (very) audible distortion.
This is the main reason why balanced interconnects are prefered for long runs.

On the other hand since we are talking about subwoofer cables it doesn't really matter as the human ear can't detect distortion at those frequencies until around/above 10% THD.

 

[mokru]

On a speaker-level cable interference of a couple dozen milli-volts doesn't cause any problems at all, but on a line-level (low-voltage) cable the interference is amplified into quite possibly be (very) audible distortion.
This is the main reason why balanced interconnects are prefered for long runs.

Yes, that is correct and is one of the primary reasons that car audio preamp voltages are rising as new equipment comes out. However, CATV coax has shielding and as the sheilding ultimately connects to ground, the shielding intercepts EMI interference. Even still run across and not along power lines...