Some recordings I hear it, sometimes I don’t. I just listened to "Time" from Pink Floyd’s Dark Side Of The Moon through BluOS and my Bluesound Node 2i, upgraded CJ PV-10AL, Emotiva XPA-2 Gen3, and Maggie 1.7is. It’s very noticeable to me on "S"s and high hat on that song. Thoughts?
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There are different remasters of that album and they sound different. Sometimes it's hard to tell which version is being streamed.

That album has been remastered so many times it's almost impossible to know what version you are getting....

That being said, I just listened to "Time" on CD and via streaming (Amazon), and neither version I heard had any sibilance in it.

I'd say your "luck of the draw" was probably just that....lousy luck.
Unless you're hearing sibilance in most everything, I'd say it's not indicative of a problem.

There is none on the album.

Real sibilance is due to a lot of energy in the 3000 Hz region where our ears are most efficient. It is also a region where a lot of rooms cause trouble. Female voices and violins are frequent affected. If you have the capability putting a 2-3 db filter between 2500 and 4000 Hz will magically make sibilance disappear. 

The usual culprits are speakers, rooms and the interaction between the two.  You can see this on a frequency response curve which can be easily generated with a computer and measurement microphone. You can also see the results with added sound deadening. 

No sibilance on any of the old quad torrents, the gold MSFL or the surround SACD.
Too bad for you.
I'd look at cleaning up my AC power (AC conditioning) and some vibration free audio stands.
"There are different remasters of that album and they sound different. Sometimes it's hard to tell which version is being streamed."

I remember listening to a couple of 'remasters' back in the late 1990s of this and Led Zep IV and being disappointed at how they sounded no better than earlier (first gen?) CDs.

In fact it appeared as if someone had simply removed some of the tape hiss and elevated the treble response somewhat which resulted in a slightly less natural sounding disc.

I've been a little more wary of any so called remasters ever since.

There's also no doubt that some folks are more susceptible to this sibilance issue than others - and I'm certainly one of them.

I've witnessed people enjoying the sounds coming from loudspeakers that seemed to have ssuch serious treble issues that I could not listen through.
Having said that, I've never heard anything said in that regard about Magnepans, any of them.
I remember listening to a couple of 'remasters' back in the late 1990s of this and Led Zep IV and being disappointed at how they sounded no better than earlier (first gen?) CDs.
I have so many different Zeppelin remasters. You're right about removing tape hiss and tipping up the highs, that's what they did to so many rock albums. This was in the 90's before the use of high compression and The Loudness Wars.
I have excellent hearing, but also have a sensitivity to high frequencies. 

Well, oddly, it comes and goes even in the "Time" recording I have in the Gold Mobile Fidelity Ultradisk! I can't afford several thousand dollars for Maggie stands nor do I need them any taller lol. I probably can't afford any fix but I am curious what's causing it.  
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It’s the Emotiva. I have 20+ versions of DSOTM and the chimes on Time are not distorted, nor are the highs. A friend with the Magnepan 1.6 or 1.7 was using Emotiva amplification and he claimed something similar. He replaced the Emotiva amps with something else and no more tizzieness in the highs.  I own the first generation MFSL gold ultra disk and if anything, the sound is dull in the treble and has a lot of tape hiss.  Try a different brand amp, that’s the problem. 
A lot has to do with the quality of the accuracy ,or lack of your digital quality , I have had many dacs from $800 to$10 k 
and it is a profound difference in musicality .
Sibilance can be from from jitter or digit er errors . I purchased a Bricasti dac with streamer module and it’s a win win more direct 
and two less cables . Also a high quality Ethernet cable to streamer is the most influential ,and second from modem to router.
Uptone audio Ether regen is one brand that cleans the dirty signals that travel from the street to your home ,for the money a excellent buy IMO, and BTW the reference Ethernet cable from Jcat audio
is a bit $$ pricy but sonically superior and I have had many up to $1500.
I noted the comment blaming it on speaker response in the 3 kHz area. That's often near the crossover to tweeters. And crossovers can be crazy. A speaker can be flat in the crossover region but if the transfer function(shape of the roll offs at crossover) are not 'nice' then there can be ringing in that area which will sound sibilant even though the measure response is flat there.
Vibration was mentioned earlier. Are your components isolated from your rack/furniture? Are you using any footers to decouple or drain vibration from the components?

My system suffered from harsh highs on many digital tracks, CDs and streaming. It took me awhile to find that the DAC was vibrating on it's shelf. I was using aftermarket footers but they weren't good enough to stop the vibration of the DAC. 

I noticed the same harshness on my system ( $ 12,000) until the Ares 2 DAC was introduced into the mix. A good quality R2R DAC would help you and really open up the soundstage on recordings from Pink Floyd.
If you're using the Node2i's internal Dac, then I agree with buddyboy. Adding a standalone DAC will improve SQ in every way. A R2R multibit has a more forgiving presentation.

Preamp has isolators not cd player (short of what was provided stock) or Bluesound 2i. 
Some recordings I hear it, sometimes I don’t.
Variations on the hearing happens too. Stress, blood preasure,... can affect female sibiliants, cymbals, high pitch violin sections. Hope will not be the case.
You had me at   Some recordings I hear it, sometimes I don’t

MC's comment above is a little cryptic to me. If you hear it on some recordings and not on others wouldn't that mean it is in the recording?  If it was something in your system wouldn't you hear it on nearly all recordings?  On the other hand what self respecting recording or mixing engineer would put out a product with such an obvious defect?  Maybe it's a stamping defect?  I've struggled with this problem for many years and I've recently made some changes that had some impact.  I've found that record cleanliness and turntable geometry tweaks have made a difference.  Sibilance is not completely gone but is way less irritating than it used to be.
I had a sibilance issue that was driving me MAD for close to a year.  I had my system sounding excellent (Innersound Eros stats and Innersound amps in those days).  SOUNDED MAGNIFICENT so I decided to make 2 upgrades (at the same time).   The bigger upgrade was replacing my Esoteric X03SE SACD Player with a new K03;  at the same time, I purchased Symposium Svelt Shelves to go under the speakers.

BOY, did I have sibilance, which I attributed to the new SACD player requiring break in;  also got it a new Shunyata $2,000 PC just in case that was giving me trouble.  More time for break in.  Making a very long story short; when I added the symposium svelt sheveles under the speakers, I did not realize I had to remove the metal feet under the speakers.  I had spend thousands to try to find/remove the sibilance.  Needles to say, once the feet were removed, it was heaven again.  
Ever consider......your room?

Of course you will notice at times....

And if you are streaming its worse.
Sometimes harsh high freq. are caused by mains pollution, which is in turn caused by RFI and switched-mode power supplies. Variations then are a result of variations in the mains. You may change the DAC and harshness disappears, but not necessary because the DAC sounds differently, just because its power supply is less prone to those distortions.
One solution that works in my setup is Audioplan PowerPlant 100S, which is just a 100W isolation transformer for my DAC. It won’t help with a poorly balanced, bright system, but if all you need is just some fine-tuning, it does the job. It has no effect on my server though, but works well if connected to the DAC ( Aqua la Voce). I’d say cotton highs become silky. And you need a resolving setup to hear the real difference.
Clearthinker, jitter sounds much different than sibilance. I had a great jitter lesson once. I was trying to set up Pure Vinyl (Channel D) and was using an ADC and DAC on different clocks. It sounded like pop corn. That was a severe case. In minor form it sounds like little pops. 

Stringreen is right. There is no sibilance in any version I have heard.

jfk011, I hate to be blunt (right) but, you have two choices to fix this.
You can deaden your room starting with the first reflection sites or you can get a DSP and program a notch filter as I previously described. This is purely an acoustic phenomenon aggravated by a bump in our ear's sensitivity in and around 3000 Hz. Google Grundy Curve or BBC curve.
It is not your equipment doing this. Cartridges miss tracking can sort of sound similar but that is distortion. Sibilance is not distortion. It is a frequency response aberration.  
That would be a huge waste of time and esp money even if my wife would allow room trat wants which she won't. I have to do all audiophilia on shoestring budget and no credit. Where do you people get all this money? Buying room treatments, much less ever upgrading a component for those kind of dollars (even interconnects and such), to me, would be the same as financing a trip to Pluto - and we make good money but we have a lot of expenses and other hobbies. If I never wanted to travel, ride bikes or motorcycles, have a car, etc. then I'd spend crazy money on audio. I can't. 

But, much more importantly,  the problem, I think, is my ears. I hear it only on certain tracks from all sources - even the car! I googled sibilance related to hearing problems there's nothing on the internet.  Guess I'll just have to suffer.