Shotgun speaker cables

Zar, It all depends on the gauge and length of the wire. Short wires on heavy gauge is best. The longer the wire the heavier gauge you have to use. If you already have short runs of 8 gauge wire or larger adding more will not be a benefit and may even hurt as you will be increasing parallel resistance (google it for an explanation.) IMHO Kimber Cable makes the best speaker wire. Their construction is brilliant because it keeps both parallel resistance and induction to a minimum and you can choose your series resistance by gauge. You can also buy it in rolls. Just a warning to those considering this, it is a PITA to terminate. It is not hard and it is worth it but plan on breaking a few finger nails.  

I tried various combos over the many years at this tweakery and settled on single (very pure copper) solid core as my preferred cable. I have my amps close to the speakers as short runs are preferable. 
Stranded or paralleled cables seem to introduce slight graininess and smearing of detail and air. Why not try your own experiment and tell us your findings?