As a brief addendum to what I just wrote, motors aren't the sole culprits for
this kind of interference. Transformers can do it too. The magnetic fields in
motors are generally many times that of transformers, but both are varying
field-intensity magnetic devices.

If you truly need the devices to be this closer to one another, experiment
with the placement of the mu-metal shield. You want to wrap it around the
primary offending component, as close as you can get it.

A full circuit of shielding is not necessary, as it would be if the
interference were primarily electric field-driven. All you need to do is
redirect the magnetic lines of force through the mu-metal rather than your
monitor.

Wirt Atmar