Bullrider97
You could also consider Stillpoints ERS shielding sheets . 11x8 for $25, at Music Direct . Lay a couple on your equipment and see if you can tell a difference . Then attach in a semi permanent manner. Also when my sound is too tight , I switch from briefs to boxers.
No offense, but I find Stillpoints ERS stuff a mixed bag. A very mixed bag. In fact after playing around with relatively small pieces of it in two systems I was unable to find a single place where it improved the sound. Now, I admit it did *change* the sound, it made it wooly and phasey sounding. Not to belabor this any more than I have to, I found that even with a sheet of the stuff lying inert as it were on the coffee table it atill made the sound wooly and weird. The only way I could get back to square one was to actually burn the stuff. Folks have reported trying smaller and smaller squares of the stuff until the sound is good. I say smaller and smaller until the pieces are zero size. If ever there was a poster child for expectation bias this is it! Hope that’s not being too harsh. But, wait, there’s a silver lining. The price has not gone up in 15 years. In fact, it’s come down.😀
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enliten
RFI/EMI is a tricky beast to handle.
It is nearly impossible to make an enclosure ’tight’.
>>>>>Especially with all those unused Input and Output jacks. 😛 Then there is the issue of RF generated by microchips inside the chassis, as I pointed out, was it yesterday? Think inside the box!
As a former designer of military electronics that were required to survive EMP, it’s quite a challenge even at much smaller audio scales.
>>>>of course EMP is not the same thing as RFI/EMI. Be that as it may. And it’s not that difficult to deal with RFI/EMI in high end electronics. Audiophiles have been doing so for many years. A good start would be to power OFF all unnecessary appliances such as fridge, TV, room purifier, even a microwave oven in sleep mode generates RF. (It helps to have an RFI/EMI meter to, you know, see what you're up against.
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That's very good. The Morphic Message Labels are in the mail. |
Pop quiz - What's the difference between heat tempering and cold tempering (Cryo)? Free sheet of Morphic Message Labels to the winner.
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glennewdick
oh Terry9 once you bend any metal you get micro fractures so when you anneal the metal, heating and cooling under control you remove the micro fractures.
Mu metal is annealed by the manufacturer prior to shipping. That’s why bending annealed mu metal won’t produce micro fractures like unannealed mu metal. Think of it like cryogenic treatment, which is what it is. The molecular structure of the annealed alloy is much more homogeneous and less brittle and more ductile. Obviously for toroidal transformers no sharp bending is involved when wrapping the transformer. You just make a "hat box." Mu metal is quite soft and malleable so for square transformers use a cylinder shaped tool to form the alloy into gradual bends around the transformer, thus avoiding sharp bends. Problem solved!
Timely tip: TAKE CARE WHEN HANDLING MU METAL. Always use those special metal-cutting scissors with beveled edges that makes a blunt edge on the alloy. It’s ok to use gloves when handling mu metal. Otherwise you will suddenly realize your fingers are bleeding since mu metal edges are very very sharp.
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That’s why you always use annealed mu metal, which all of it is these days, since annealing improves performance considerably. Why wouldn’t you anneal it? And why you wrap the transformer without putting sharp bends in the metal, easier I suppose for toroidal transformers than for square type. Just ask for Ultraperm.
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kavakat1 OP
So, would a sheet of mu-metal placed on the bottom of each shelf between components help? I have a NAD integrated amp, and one shelf below is my OPPO 105. Shelf is MDF
Since the primary culprit of magnetic fields by far is the large transformer, the ideal solution is to completely wrap the transformer with one or two layers of mu metal, which is quite flexible (and SHARP). As I recall one layer absorbs 77% of the magnetic field whereas a second layer increases the performance to 95%. A space of 1/4" should be maintained between the two layers. The correct type of mu metal is low frequency high permeability mu metal. |
Electromagnetic waves are very flexible. 😀 The Schumann frequency waves wrap around the room. It would have to be the full wavelength as shorter wavelengths wouldn’t be 7.8 Hz. Can electromagnetic waves enter the component via unused input/output RCA jacks on electronics, even though the chassis case is metal? I wouldn’t bet against it. It's also interesting how a Schumann CD can generate a 7.8 Hz acoustic wave in the room through any speakers, even computer speakers, no?
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nonoise
A quick look at Wiki states that any hole or vent has to be significantly smaller than the RFI/EMI wavelength in order to stop it. Good luck with that. It enters through any connector not used as well as any cable not completely shielded. Also, AC brings it through your PC.
All bets are off how small or big a space has to be to stop or prevent or disallow an electromagnetic wave once the Schumann frequency raised its ugly head. You know, the 7.8 Hz wave that sets up in a listening room when generated by a Schumann frequency generator, since the wavelength of that particular frequency is around, what 26,000 miles? Yet it has no problem fitting into the room. Yeah, baby! |
RF is like germs. It’s like Chickenman. It’s everywhere! We're drowning in a sea of photons. Since RF travels at lightspeed it’s eveywhere at the same time. It’s inescapable. It infiltrates any and all holes or gaps anywhere. It enters the unused wall outlet prong holes wherever they might be. RF then contaminates the house wiring (unshielded), then RF enters the electronics via power cords. The PC shielding only protects against external RF. Hel-loo! Regardless of the metal chassis. Since RF is also produced by microchips INSIDE electronics such as CD players not only is everything inside the chassis contaminated but the signal going to the amp or preamp is also contaminated. The enemy is inside the gates!
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OP - Why are we trying to quiet the rfi to and from our amps, transports, etc when the metal case already does it?
I could tell you but then I’d have to kill you.
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