Subwoofer cable question for those in the know...

My preamp has an extra set of line level outputs to drive a powered sub.

Would there be any advantage to running separate L/R cables since it is purely a bottom end booster, or can I Y the signal out/signal in and run just one cable between pre and sub?

Also, what is the difference in construction between "subwoofer cables" and ordinary shielded RCA cables?

I haven't seen anything definitive, and I assume they are designed to carry just a low frequency signal better, as opposed to full range signals?

Advice, of course, is greatly appreciated.

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As they only need to relay lower frequencies, sub cables don't need to be as highly configured as regular speaker cables.
Even Vandersteen supplies rather ordinary cable with his subs. I use Cable Solutions, as recommended by Almarg.
Without knowing what sub and pre you are using limits what can be recommended.
For me, using a powered subs, I use two runs from the amp-one for speakers, and one for the subs if I don't have a crossover. Since both speakers and sub share the same signal, integration should be easier.
There is a slight difference in running 2 separate cables to the L/R inputs on the subwoofer vs. using a Y adapter at both your preamp and sub.  On my system, the 2 separate cables sounded a little better.   It's not a big deal and many wouldn't hear any difference at all.   I was using a VMPS sub and VMPS ribbon speakers.  They have very good definition.

I think one cable is fine. sub is mono. "Y" adapters can do more harm than good

To answer a few different posts and provide some info...

I have a JBL 8400P sub and it has both L/R line level inputs, 50-150hZ variable crossover control, phase switch etc.

AES3-MKII preamp (made by Cary) which has 2 sets of L/R line level outputs.

It is feeding a pair of modded Dynaco MKIV monoblocks. (Must give grannyring some props here. He rebuilt/upgraded these things, and they are beautifully done, as well as sounding incredible. Really nice guy too, as others have said here.)

The JBL manual gives as an option putting a Y inline if your pre-out is only a single RCA jack, so I don't see how it could harm anything to Y the connection on both ends, as stated previously it is mono.

I have a large volume room with hardwood floors, which makes my sound a bit on the bright/thin side with some recordings. I am just wanting to tinker with the sub to see if it makes the bass deeper without being too muddy/booming, and I didn't want to dump a fortune into cables (it's about a 10-12ft. run from my rack to the sub) just to find out that it was not much better.

Thanks for the feedback so far.

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