Microphone cables and TRS (Tip-Ring Sleeve) cables are no more difficult to solder than are Guitar or Patch Cables, There's just 1 more wire in them, that's it. If you can make a Guitar Cable-then you can certainly create Microphone Cables!
Just remember to be patient.
XLR Microphone Cables.
TRS Tip-Ring-Sleeve Connectors for Y-Cables.