Building Balanced XLR Cables

Hi

XLR cables should have two conductors and a shield. NOT 3!
Do not use the 3rd conductors for GND.
Use the shield.
Shield is significant to protect from EMI/RFI. use it as GND.
Two ground lines (3rd wire and shield) may cause a ground loop and add hum.
Not to say it is not the standard XLR.
XLR (Balanced line) is a long lasting standard, used in so many applications and configurations.
It works.
Why change?
Just because you purchased the wrong cable with a 3rd conductor?

I would take b4icu's suggestion with a grain of salt.  It may be true in some specific circuits, but not all.  See this guide:

https://www.ranecommercial.com/kb_article.php?article=2107

The shield connection on the XLR is basically connected to chassis/ground.  This may be completely different than pin 1 "signal ground".  If you have a cable that has 2 conductors and a braided/foil shield, you can connect the shield to "pin 1".  This is common shared signal ground and may be required in some audio circuits.

That being said, I have have had great success in making cables that use three 20awg solid-core conductors in a braided configuration for pins 1, 2, 3.  I don't connect anything to XLR shield/chassis.  This is very similar to how Kimber Cable makes their interconnects (but they use stranded conductors).

ah, just re-read your first post.  If you have a braided wire shield, I would solder that to the "shield" connection on the source XLR plug (typically a female plug).  If you have a "floating" braided shield, it tends to create capacitance and reduces high frequency response in the cable.

Then tvad they are not balanced. Pin 1 has a shorting contact to the XLR housing. There is no forth ground. The proper wire is three conductor. The forth wire is there I believe for powered microphones. Any interconnect without a proper shield is asking for it.
You hook the shield up to pin one and leave the third wire unused at both ends. You use a floating shield in power cables. You are floating it to prevent ground loops.