I am thinking re-postioning my system which will involve longer speaker cables.
I am currently using Superlumina cables and given the expense of replacing them with longer cables (from 6 to 9 m) I thought of trying phono couplers and buying 3m cables to increase the length.
Probably not a good idea but I would be interested to hear from anyone who has tried using couplers.
I’d suggest that you sell the 6m set and buy a 9m set. Maybe you can find some of the longer ones used and save a bit. When I rearranged things I sold my 3m set and bought a 4m set to replace them. With cables at this price it would be a shame to compromise.
Don’t do it. Sell them and buy another set. The price difference will be relatively marginal if you get used. I got 7m for 3k GBP with abit of negotiation.