Can you tell us the length of each wire run? That is the anticipated length from the amp to the farthest speaker?
If all the distances are less than 50 feet, there really is little or no need for wire that heavy. 2.5mm² is more than enough.
The particular cable you are looking at is low capacitance, and given what little I know about the general construction, it would likely be low inductance as well. Consequently the only thing that matters is Wire Resistance which is about using nearest equivalent in AWG wire,
* 6mm² is about 2.6 ohm per KILOMETER.
* 4mm² is about 4 ohms per Kilometer.
* 2.5mm² is about 6.5 ohms per Kilometer.
That means an entire 100 meter roll of 2.5mm is only 0.65 ohms. 10 feet is 0.065 ohms. Generally, if you stay below 2% of the speaker resistance you are fine. 2% of an 8 ohm speakers is 0.16 ohms, 2% of a 6 ohm speakers is 0.12 ohms, and 2% of a 4 ohm speakers is 0.08 ohms.
If you want to spend the money, then fine, it is your money. But as I said in your other thread, unless you are connecting a car battery or 1000w/ch amps, they is NO need for 6mm and very little to no need for 4mm.
Using the nearest AWG gauge wire, 6mm, assuming that is 6mm², is about 9.5 gauge with AWG 9 ga wire being 6.63mm² and 2.6 ohms per Kilometer and AWG 10 ga wire being 5.36mm² and 3.3 ohms per Kilometer.
I've not been able to find similar specs for Euro sized wire, so the best one can do is interpolate from AWG wire for which full specs are easy to find.
Hi, I ended up buying 30 metres of Van Damme Black Series Tour Grade 4 x 4.00mm multicore, after speaking to Joe @ The Media Factory Media Factory - Home Theatre News! the cable is really heavy and looks the business also. Excellent service and advice.