[LAU] Rumble noise from mic

[lanas]

Hi all,

  When using the M-Audio Pulsar mic I notice a rumble sound until I
touch the mic, in which case the rumble goes away.  That sounds like a
'ground' problem of some sort.  The mic is connected straight into a
M-Audio 1010 PCI card using one of the XLRs jacks. The 1010 card also
has M-Audio active speakers connected to it.  

  The computer plugs into an electrical extension to which monitors and
other devices are plugged.  That extension goes to the wall plug and is
of the three prong type (North America).  Now, it could be that the
house electrical outlet wiring is not right.  Would that be the
problem ?  Is there any other way to solve this ?

  Gating the signal would hide the rumble when there's silence but
that's not a solution.

Thanks for any suggestions/hints/ideas.

Cheers.