Do you believe in Magic?

Wow, Al. Stillpoints should hire you to write copy! :-)

Seriously, thank you for your thoughtful answer. You are great at putting things in terms that folks like me can understand. I know that your explanations are partly speculative, but acknowledging that, there is still something that puzzles me...

How is it that SO LITTLE conductive material can have a perceptible effect on sound quality? Am I wrong in my assumption that diffusion/reflection/absorption of EMI/RFI typically requires something more substantial?

bc

How is it that SO LITTLE conductive material can have a perceptible effect on sound quality? Am I wrong in my assumption that diffusion/reflection/absorption of EMI/RFI typically requires something more substantial?

Hi Bryon,

That's a good question, and I would think the answer is that it is only a small subset of the digital and analog circuit points in the components that need to be protected from the effects of rfi.

Assuming reasonably good design, the only digital circuit points that would be susceptible to rfi-related noise are those at which jitter might be an issue. That might be a small handful of circuit points, or even fewer. And only a few kinds of analog circuit points are likely to be susceptible, such as what are known as "summing junctions" that are within wideband feedback loops. So judicious placement of the material near those points, or near sources of rfi that could affect those points, would presumably be sufficient to make a difference.

I note that the Stillpoints web page on the ERS material states that "effectiveness will be maximized when placed internally near either EMI/RFI generating or EMI/RFI susceptible circuitry within the enclosure."

Best,

-- Al

That all makes sense, Al. Still, I feel like there's still a touch of Magic in it, in the sense I stated in the OP.

Among the stranger things commonly reported about ERS fabric is that using too much of it tends to diminish high frequencies, as Chad described in this thread. That is puzzling to me. Could it be that using too much ERS fabric somehow affects certain circuits in the way that high capacitance interconnects can act as a low pass filter?

And something else you said struck me:

...the only digital circuit points that would be susceptible to rfi-related noise are those at which jitter might be an issue.

Eureka! THAT explains my experience with ERS fabric. The two changes I reported in the OP were...

--the decay of notes
--instrument timbres

...both of which I associate with jitter. That association is a result of my experience adding a reclocker to my system. The raison d'être of the reclocker is to reduce jitter. Adding the reclocker provided me with an impression of what jitter sounds like, or more importantly, WHAT THE REDUCTION OF JITTER SOUNDS LIKE...

It sounds like what I heard after installing the ERS fabric.

This explanation is consistent with my placement of the fabric:

1. preamp power supply
2. reclocker (with an Audiocom Superclock 4)
3. preamp master clock (another Audiocom Superclock 4)

#2 and #3 are both digital circuits where the amount of jitter has a significant effect on sound quality. I think I can say with a reasonable amount of confidence that the ERS fabric is helping to reduce jitter.

Thank you, Al, for leading me to this realization. I still don't know whether Magic exists, but I am more confident that the changes I heard exist in my listening room and not in my mind.

bc

You're welcome, Bryon! Glad I was helpful.

Among the stranger things commonly reported about ERS fabric is that using too much of it tends to diminish high frequencies, as Chad described in this thread. That is puzzling to me. Could it be that using too much ERS fabric somehow affects certain circuits in the way that high capacitance interconnects can act as a low pass filter?

I suppose it's conceivable that the presence of the material could affect the amount of stray capacitance that exists between various circuit points. But I would expect the sonic effects of that, if any, to be highly inconsistent among different components, and among different positionings of the material.

A much more likely explanation, I would think, is that low level broadband noise (i.e., hiss) in the upper treble region is being reduced, and that is being subjectively perceived as a diminution of the highs.

I've seen it stated in a number of articles that I've read in the past that low level high frequency hiss tends to be subjectively perceived as "air" and ambience. Which would seem to make sense.

That reduction in high frequency low level noise could conceivably occur either in digital circuitry, via effects on the amplitude or spectral characteristics of jitter, or in analog circuitry, via effects on the amount of noise that is directly coupled into the signal path.

That's my speculation, anyway.

Best,

-- Al

I used a liberal amount of ERS fabric, and I didn't notice a diminishment of high frequencies. That could be because of where I placed it, or if your hypothesis is correct, it could be because it merely removed some high frequency hiss.

I agree with your observation that some audiophiles perceive high frequency hiss as "air" or ambience. Personally, I tend to perceive it as noise.

In fact, with the ERS fabric installed, I can say that there is simultaneously LESS hiss and MORE ambience.

bc