i need 20 meter speaker wire, decent quality

If the long speaker cable alternative is chosen, IMO there is a question which has not yet been raised that is essential to selection of an appropriate cable. And that is the impedance characteristics of your speakers at high frequencies.

I did a quick search but was unable to find an impedance curve for your speakers. Perhaps you can obtain one from MBL, or from a dealer or distributor, or by searching further with Google. If the impedance at upper treble frequencies does not rise substantially above its 4 ohm nominal value, then the inductance of the 20 meter length of cable becomes a significant issue. Relative to 4 ohms, the inductance of your present wires, and the inductance of 20 meters of Anti-Cable, and the inductance of ordinary heavy gauge wire, will all very likely be significant enough to perceptibly dull the extreme upper treble, and to cause perceptible sluggishness of sharp transients.

A major reason that the OCOS and Goertz cables that were suggested above tend to be good for long runs is that they have extremely low inductance. However, they also have extremely high capacitance per unit length, which would be factored up by the 20 meter length to levels that MIGHT be problematical for some amplifiers.

IMO, if you determine that the impedance of the speaker at upper treble frequencies is not considerably higher than its 4 ohm nominal rating, and if you settle on the long speaker cable approach, the Kimber 8TC that was recommended by Elizabeth would provide an excellent combination of low inductance, reasonable capacitance, and low resistance. The 12TC she also suggested is even better in those respects, but I suspect that it may be overkill.

I also agree with the comments that if your components provide balanced xlr interfaces, and assuming the sonic performance of those interfaces is good (which is not always the case), the long interconnect/short speaker cable alternative would be highly preferable. If you have to use unbalanced rca's, Bryon's suggestion of splitting the difference is also a good one, if feasible.

Regards,
-- Al

Al brings up good points. I use OCOS for a 5.5m run and have no problems with it. I have used Alpha Core MI-2 Veracity and feel it is one of the best values in audio. However, with solid state amps (and to be safe tube amps as well) it is best to get the zobel networks that can be provided with the cable. When I bought mine the zobel networks were free and were integrated with the cable.

Well said Al and those mentioned in his post.

As Al said the if the attributes of balanced XLR connections are up to snuff, then that is the way to go.

Best

Dave

I appreciate all your input very much. I spoke with John at JW Audio at great length and he was very helpful. I ordered two 75 foot bi-wired speaker cables from him. He has great feedback and seems to be a very likeable guy. I will use them for 30 days and if I don't like them I can return them for a small restocking fee, which seems very fair. I will have a professional installer run them up and down walls on the inside. In fact that is what makes the runs so long. If i could run them as the crow flys it would about half the distance.

Thanks agian for all your help. I did speak with MBL and Krell and they both suggested this is a good way to go. We shall see. I am sure it will be much better than the 14 guage braided cheap wpeaker wire I have been using for the past ten years.

You might check with your installer to see if it would be easier for them to run 2 separate runs of the solid core cable through the walls at a time if you were thinking of having the cables bi-wired on the amp end. The solid core wires are fairly stiff, and trying to push or pull all four cables from a bi-wired pair through the wall at the same time may be a bit tricky for them. They will go through easier in most situations one pair at a time. You would then just attach both spade ends (2) to each output binding post of your amps for the two pairs, instead of crimping/soldering the wires into a single spade at the amp end. This "double run" would be the same sonically, but possibly easier to handle around tight bends in the walls if that might be the case.
I just noticed that you showed two different stereo amps. Are you bi-amping the speakers with the two amps, or just using one of the amps and bi-wiring it to the speakers?