Originally Posted by pheria
I didn't have a real compass to test with, so I tried to use the compass feature on my phone. It seems like within 4 +/- 1 inches from the sub is enough to interfere with my compass. So that gives me an extra inch or so to the bottom of my case, and the hard drive isn't even mounted on the absolute bottom. I think the magnetic field is dropping off quickly enough.
Compasses are pretty easy to interfere with. The Earth's magnetic field has a strength of ~45 µT. My Z2300 sub maxes out at 1700 µT on the top. According to this, degaussers have a coercivity (not measured in teslas like magnetic field strength, but related) starting at 5000 Oe (oersteds). Somebody else pointed out that a ferrite magnet with a coercivity of 2000 Oe has a strength of 0.4 T, so my sub is 235X weaker than a magnet that's even weaker than a degausser. All things considered, I'd say it's safe.