I made a 4W silver plated copper cable using Toxic Cables Viper 24awg OCC Cryo Silver Plated 7n Copper.
CEMA/Electro Acousti 4.4mm jack and splitter. Cardas eutectic solder. Memory wire ear guides. 4ft long.
This was made by me just to see what it sounded like. With my setup, the was a definite improvement in definition and separation. Probably best for warmer phones where you want a little more resolution without sacrificing bass quantity.
The cable is a little stiff, which is why I made memory wire ear guides which improved the ergonomics greatly.
Disclaimer: this was a personal project. I do not do this for a living. It is being sold at less than cost.
£39 including PayPal fees and postage to the UK. EU postage is extra.
Happily consider any cables of equivalent value as trade.