Speaker cables to smoothen things up


I love the sound of my system. Its dynamic and neutral and very lively. However, my taste to music have melowed somewhat, and im prefer a smooth, relaxing sound at the moment and was wondering if a speaker cable change would smooth things up somewhat and reduce the hardness and attack from my system ( not bright, just hard)
My speaker cables at the moment are some synergistic research tesla quad. I got this for free from my brother therefore ive not tested other speaker cables.
Interconnects are tchernov reference cables and my subwoofer inteconnects are fat oval ic.

The chain goes as follow
Mac mini with audirvana - nad m51 - densen b200 -densen b330 - neat ultimatum mf5 and genesis g928 sub.

Was wondering if a speaker cable change would smoothen things up. Its not to reduce the brightness of my system, my system is pretty neutral. Just want to reduce some of the attack and dynamic off the system. If possible, not wanting to change the amp and speakers.

Ive heard about van denhuls to do this, and ive got a good deal for a d352 hybrid cables. Also a good deal for a kimber 8tc ( the older black and blue version). Would these help? Any reccomendations is much appreciated

Just for info, my room is almost fully treated. Big drapes and rugs and diffusers and bass traps all over.
nieveulv
Agree on Cardas...would also suggest for the money to try some older Transp Reference cables...you can find them here for cents on the dollar. I would go back to 10 year old cable...the reference level or above. There was Reference, Reference XL to start with. Very smooth, dark backgrounds...in fact some say they were designed when the original Wilson X1 series was still around...and being quite scientific in the treble, the combination with Transp Ref worked quite well.
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Before you buy new speaker cables, make sure that your cables are properly dressed. I.E. make sure that interconnects and speaker cables are not run parallel to power cables. If they must run parallel, get as much distance between them as you can manage. If they cross each other, do so at 90 degree angles or as close to that as possible. I realize that many audiophiles understand this, but most certainly some do not. It can make a substantial difference in the amount of noise/hash in your system. It can manifest itself as harshness when listening. The best things about this is it's easy to do and free. Hope this helps.