Speaker Treatment To Resist Negative External Infuence


I have been trying some experimental work with high end audio lately. One of the problems is the electromagnetic interference from many sources outside the box with the audio signal once in the cabinet. I have pondered how to solve this and got to thinking about metal flake paint for this some time ago but just now testing the idea. So far the larger flakes seem to work best as they tend to lay flatter parallel to the speaker exterior surfaces. Smaller flakes did not do as good as they floated more and settled in random manner as the paint cured.
   Steel seems to work best at resisting inductance from things like power cords. Copper worked best for things like Blue Tooth problems and any other RF induced hysteresis  interference.

  I have tried radially coating the sides, top and bottom all in the same direction insofar as flake alignment and the back top to bottom. It seemed to mellow out high notes of stringed instruments and acoustic music where the string snap and even finger movement sound was audible for the first time and percussion was more vibrant and true to life. In general the definition of most music improved and sometime the difference was not subtle.
  The best combination was a 50 50 mix of copper and steel flakes at this time. As testing continues I may change my opinion here.
  I also tried a radial pattern on the sides,  top, bottom and back.  The "Faraday" paint would be applied with a brush beginning with the center of each side and brushed out radially. Now I would also apply more coats going in to the center for a progressively thicker layer as you approached the very center of each side. This yielded different effects and primarily seemed to benefit mid and lower frequencies. Cello resonance was profoundly stirring and pipe organs were like you were there. Jazz and Blues with five string bass notes in particular had better presence and the size of the sweet spot grew considerably.

  I never dreamed this would be the result that day I looked at some metal flake paint.

 
mahlman
Doesn't RF get through the driver cones? I think what you're hearing has more to do with the paint adding more mass to the cabinet.
You can ground the woofer chassis to the internal speaker ground lug or you can do the same with a metal stand but not as well when resting on sponge or springs.Tom
" I also use magnets to alter material direction of the coating but this can only be done on some material combinations.Tom"
  I can see that and to bad there is no copper magnet. I have seen copper wire jump under capacitor discharge before and maybe there is a way to induce an effect in copper.
  " Typically I lay down a layer of blue tape and paint the tape. "  Funny how I could miss a simple thing like that very practical idea when doing all this.
  " Very interesting.. "Radial" you mean like a picture of a sun with the rays radiating from the center? Straight lines from a center point? Complete 360? "
 Yes
" Doesn't RF get through the driver cones? I think what you're hearing has more to do with the paint adding more mass to the cabinet. "
  Yes some does get through I am certain but far less than before. I would agree with the mass idea except using differing coatings on different cabinets yielded different results. Now I know the plywood could be variable so I used some out of the same production lot. I think I will weigh these cabinets both before and after to try to determine if they add enough weight to become vibration dampeners.

 
Paint is absorbed thru the pores and glue of the wood sealing the wood and changing the shear and vibration path. Mass in this case is less a factor than shear velocity.
The cabinet is a passive radiator of sound but dont over damp with soft goop because that will become the instrument. Tom