Should I use long interconnects, or long speaker cables?


Currently, my equipment rack is placed centered between and behind the speakers.  I’m getting acoustic feedback (rumble) from my tt due to it’s location.  Successfully, I have eliminated this rumble by using a KAB rumble filter.  However, this seems to me like a bandaid approach, and I would like to try to eliminate the use of this filter if possible.  I’m thinking of moving my equipment rack to the side wall to try to eliminate the rumble filter.  My question is, there are two ways to do this.  Is it best to:
#1). Move everything (including the amplifier) to the side wall, and use long speaker cables to connect the amplifier to the speakers.  
#2. Move everything, except leave the amplifier on the floor (on a separate amp stand), and run a long interconnect (20’-25’) from the preamp to the power amp (my preamplifier is single ended only)?
In advance, thanks for your guidance!
louisl
Conventional wisdom is to use long interconnects, rather than long speaker cables--the theory being that long runs will do less damage to low signal than high/amplified signal.

I put the theory to use in my 1st house, where the big Vandersteen 4 speakers (each w/integrated dual 12" push-pull sub) was located ~25 ft from the source hardware. As the 200 WPC SS amp for the subs & tube amp for mids/highs were located as close as possible to the Vandies, but off to one side, that meant:
  • 2 X 25 ft runs of interconnect 
  • and ~9 ft. pair of speaker cables 

The resulting sound was amazing. Once I heard that, I never thought twice about the wisdom of my cabling.

BTW, it does make sense to make sure your interconnects have relatively low capacitance--as that is one spec that definitely "accumulates" w/greater length. My interconnects qualified, plus I knew they sounded great from previous experience.
With single ended (non-XLR) interconnect cables, you are in more of a pickle. XLR is designed for longer runs, single-ended ICs are not. 

Longer speaker cables impact the sound. Shorter the speaker cables, the better.  Long runs of quality speaker cables can be expensive too. 

As suggested, isolation. Worth more exploration, granite slabs, layers...
If your preamp had xlr output and your amp xlr input, use longer xlr interconnect.
How long is long? 5 to 7m length speaker cables is still manageable. Some amp manufacturers such as Naim actually recommend to have longer speaker cables for optimum results (better sound).