[sdiy] How to design out "usb noise"?

[Mike Beauchamp]

I recently stumbled across this post on reddit of someone showing usb 
connection causing some serious noise: 
https://www.reddit.com/r/synthesizers/comments/1aghqsa/how_to_get_rid_of_usb_noise/

Some comments suggest to use DIN MIDI instead of USB MIDI as a solution, 
but it got me wondering if there's a best practice for implementing MIDI 
OVER USB output that wouldn't cause this. MIDI spec includes schematics 
for hardware implementation of DIN MIDI connections as we know, 
including the use of opto-isolator, but I can't find the equivalent for 
the USB connection.

A typical USB-B connector has the following pins:

1. VBUS
2. D-
3. D+
4. GND
5. SHIELD

How do you think these connections should be handled inside the synth, 
assuming a hostile environment where connections are also being made 
to/from a PC with audio cables, MIDI cables, power adapters to different 
outlets/circuits, etc.

Mike