"I use the MD-03 as a device for resonance control on top of my loudspeakers,
on top of a power filter and in the fuse box on top of the electric meter.
The sound is fuller, much more powerful and at the end more real. This are keepers. Thanks a lot..."
  (2020.2.25.  J.S. from Germany, bought with MD-03 & Reso-bell large.)