Synergistic Research Black Box -

The Black Box is sensitive to placement and
vibration control.  I have brass fishing cones
pushed through the spikes and rosewood blocks
on top of the edge of the unit that is closest
to the wall.  I can hear a difference in the sound
resulting from the smallest adjustment of
proximity to the wall.  For me the Black Box is
indispensable.

Big improvement when I vacuumed the five perforated sides and thoroughly wiped the underside of the Black Box.  Dust happens.