Nick Meade has published a very detailed tutorial on his blog about creating custom cables for a microphone setup that he uses for MS stereo recording. Of course the tutorial works for any cable and any job.
One of the lessons I have learned in my career is that good gear is hard to find. Great purchases always require a decent amount of research and even then you may not always find what you are looking for, especially in the specialized world of sound effects recording. For example, I was recently in the market for a 2-channel cable for my stereo MKH-30/MKH-60 combo rig. As there were no commercially availble solutions that I was particularly fond of, I decided to build a cable from scratch with the exact materials I would like to see in a quality stereo mic cable.
My goal in this tutorial is to show the basics in custom cable construction, not specifically give instruction in soldering. For specifics in the art of soldering check out YouTube and enter a search criteria such as “How to Solder,” where I was easily able to find approximately 5600 videos on the subject.