Absorption of digital hash

Berkeley uses material to absorb stray digital noise. Anyone know what they use?


I use Mu Metal foil to shield my step up transformer from external EM fields and resulting noise. Works great.  The difference in noise levels is clearly audible. 

I used my golden plate homemade device : a plate of shungite with an external copper tape face + in some case mineral as quartz to fine tune the sound...😊

I used mostly  very thin plate unlike the example of this image


Thanks guys. I've found Holland Sheilding System as a result of your helpful comments. Now will do some shopping :)

OP:  Not sure what you are doing, but please keep in mind the heat dissipation of some devices.  Wifi routers especially need a lot of airflow to function at top speeds, and may even shut down.  Modern, Energy Star compliant Ethernet switches should be fine though. 

@erik_squires . Like to improve my Oppo 205 without any upgrades. Just read about Berkeley as I'm considering dac upgrade ( or Spectral spinner). Still love disc movies on my Sony 4k. Mu metal for transformer 'may' be interesting. I'm just getting back to listening. Been busy w project. Relaxation coming up-again :)  Time to ponder hi-fi improvements. Your comments always interesting/informative/ mannerly :)