No one actually knows how to lculate what speaker cable they need

Good point. I won't involve myself and perpetuate the misunderstanding.
That said, I am in a position to try it, so I will.

Much like b4icu's 0 awg cable recommendation. It's going to be an experimentation week.

Some say about this thread.

Not like many other threads, this one has a theoretical (engineering) side and a practical side. We can long argue the theoretical, till the practical part knocks on the door.

So far, only one got there. More are in the process. I would advice to be a little bit more patient and read what that will bring with their generous sharing. I hope that then the party will really get excited.

Each one, who took thing in hands, may have a little bit different implementation to that cable. Also they have different setups. The principal will remain the same. So should be the results.

If I'll take Mr. keppertup as an example (a very good one), I can assure you he is satisfied with the results and will not look back to exchange the new cables with his old once. He is the first for you, but I have more…

Before this happens, I am worried a bit. So I was with the other once. What will be the reaction to that change? Even thou I hope for the best. So far, things look pretty much consistent. There is no convincing on my side. I won't benefit from those who reject the idea or think different. I do benefit from those, like Mr. keppertup, who report of getting from the very same equipment with a new wire (cable) a way better sound. So far this is my reword. For me it is a big one.

If on the way, I can help some with other things, it would only be a benefit. However, I wish this thread do not turn into some infertile debate over one (or more) of some urban myths. Attempts were so far successfully pushed back.

@b4icu. My Lyngdorf 2170 does not list the DF spec as you know. You speculated 250. I emailed them and they say the speaker cable’s impedance is much more import and the thus the DF and output impedance are not given for the amp. It is a powered dac. They said the unit has no negative feedback loop and the damping factor is very low. I think the DF is closer to 100. My speakers are Dali Epicon 6s. My cable length is 20 feet and unfortunately this cannot change. Would you still recommend 3/0 AWG. 

Lastly, one side can be 8 feet, but the other has to be 20 feet.  

b4icu, I’m sorry you have been subjected to such rudeness on this thread. There are certainly much kinder and gentler ways to disagree with somebody over their ideas. Also, and nothing to do with speaker cables, I did enjoy your aside about your daughter’s military service. You must be very proud of them.

I am new to the field of high end audio wiring and am trying to learn about it. I have recently purchased two new speakers, Magico A3’s, to be delivered in February, and a new amplifier, a Luxman L-507uXII, I’ll be picking up this week.

The Magico A3’s will be located 4-5 feet to either side of the amplifier. The wires will also have to travel about another 3-4 feet to get to the height of the Luxman amplifier off the floor and then behind it to the amps connectors. Worst case scenario, maybe ten feet of cable to each speaker will be needed. The Luxman has a listed damping factor of 260 . The Magico’s are rated at 4 ohms impedance, if that has any relevance.

What would you recommend for sizing and creating speaker cables in this instance? And what might you guess or estimate it might cost to create them as you’ve described? If there is any other information you need, please let me know and I will obtain it for you. Thank you for offering your assistance to Audiogon’s readership.

Michael

Mr.  grannyring

The Lyngdorf 2170 is a digital Amp. par excellence! those usually come with high DF. Very high...(theoretically something like 5,000!) on other posts (private one) an other maker would recommend of an equivalent DF of 1,000. However you've been told that it has a DF of 100. It is a 10x ratio difference!
As so, I would go for your cables in two options that you will have to make up your mind, and take a decision of which one you like to believe to

 
For 20 ft long:
For a DF of 100 it would be a 1 AWG (I would take a 0 AWG that is more popular to find and work with)
For a DF 1,000 it would be a 4x 0 AWG in parallel, or 2x 4/0 (0000) AWG in parallel. This is a very thick and heavy cable.
The set would be over 40Lb. I doubt if you can do a DIY cable of such size.

If the 100 is your choice, and the real DF is more like a 1,000, you are still at enjoying only 50% of your system. If your choice is the 1,000 whatever the trouble to get it, you will end up with the right cable, of way more (not really required) and expensive cable. Up to you!