End of a long quest to vanquish sibilance.

I still remember the time I had finally gotten a really great (for me) setup:  Brand new 25wpc OTL tube amp, Reference 3A DeCapo I speakers, Pioneer RT-909 tape deck, Music Hall 7 TT with MC cartridge, and a $1K dac/preamp that was supposed to be SOTA at the time but I hated the sound of it (bleeding ears is the best way to describe it).

Anyway to make  a long story short, I was listening one night, everything sounded fantastic, and I remember turning my head a fraction of an inch, and hearing a BIG change in the highs. Hmm, what the heck?

Tried turning my head back and forth repeatedly and yep, the change was very noticeable and easily repeatable.

I have never since been super-fussy about perfect highs (except like OP finding a way to eliminate sibilance), realizing that if a big change would occur from turning my head a fraction of an inch, then chasing perfection was a losing proposition unless I went permanently to phones...

@stuartk glad to hear you were able to eliminate that nuisance. Your perseverance paid off! I’m actually not in a least bit surprised. I’ve not had good experience with platforms/vibration control devices with any components I ever owned owned. Good solid rack or amp stands is what worked best for me. Enjoy the music!

@decooney

Thanks.

Life without music is a grim prospect!

Now I’m back to enjoying listening with a system that has no glaring imbalances-- not a bad foundation from which to proceed when finances allow.

Congratulations to you @stuartk for not giving up and continuing to try different things until you figured it out. Glad it worked out and you are back to listening to music once again 

@noromance

I would, too but to be to honest, my focus has, so far, been on enjoying listening again.

The fact that I had the same speakers, same stands on the pavers with different (less resolving) electronics and experienced no sibilance remains a mystery to me but I’m a music lover who enjoys good sound rather than a bonafide audiophile. I lack the technical background that might help me understand what is going on in terms of physics. 

@stuartk  Great that you sorted it out. I would like to know what physics were involved in the cause though. 

@steakster

Thanks.

Yes; I’ve tried covering the coffee table and I didn’t notice any sonic differences. Same story with draping blankets over the slate hearth/glass fireplace insert. I’ve experimented with this several times.

As you can see, I have very limited potential locations for subs.

@gdnrbob

Could you explain it in layman’s terms?

@steakster I know what you mean about the coffee table. My son is familiar with working in a recording studio and was convinced that I should try Dirac Live. So, we tried it. My room measured reasonably flat, so I didn't bother to buy it.

At one point in the measuring process, we were getting a weird spike (or dip, I can't remember).  I had my laptop sitting on a coffee table with the screen up.  We closed the laptop and the abnormality went away. 

From my experience, I think you are sensitive to Time and Phase coherence.

Bob 

OP: Congratulations! Glad to hear that the years-long mystery is solved. Yes, everything matters!

As per the photos in your virtual system, the coffee table has a very reflective surface - not only for light waves - but also for sound waves. Changing the height of the tweeter changes the angle of reflection off the coffee table - as any pool/billiard player would appreciate. By any chance, have you ever put a blanket on the coffee table to observe if it affects the SQ?

Also, adding a subwoofer (or two) will help to fill out the sound field. When I added LF, I was surprised how the HF became relatively more mellow - more integrated into the entire presentation. Enjoy the music!

@12many

It would be interesting to see if a rubber or heavy fabric pad between the floor and the paver and the paver and the stand would also remove the sibilance.

FYI, I have Herbie’s gliders attached to the bottom of the stands. Sorry for not mentioning this earlier. They didn’t inhibit the sibilance.

I am always trying to improve the upper frequencies which sometime trouble me. 

I’m very sensitive to high frequencies/bright sound. 

In my case, there was fatigue, but it was due to the DAC I was using at the time, not the pavers. Once the DAC was removed from the system, the fatigue went away. It was not a subtle improvement!

Hope you're able to tame whatever is causing you trouble. 

Can anyone comment on why these pavers (or similar) would be causing sibilance?  I am always trying to improve the upper frequencies which sometime trouble me.  I know my speakers are not traditionally fixed to my floor with the supplied isolator fee.  

@stuartk It would be interesting to see if a rubber or heavy fabric pad between the floor and the paver and the paver and the stand would also remove the sibilance.  

@ozzy62

Thanks.

It’s certainly a great relief and fine for now. It’s a novel experience hearing vocals without being assaulted by distorted plosives and ssshhh "trails".

I do miss the bass response I got with the Aqua DAC -- the Hegel H390’s internal DAC definitely lags behind in this regard but then, the Hegel’s DAC is not at all fatiguing.

l’ll demo standalone DACs when I can afford to do so.

@acman3 

Yes!  

Good deal! In the end it doesn't matter if you figured it out or got lucky. Glad your happy.

Congrats on solving the issue. It’s a good feeling when it all comes together.

@ghdprentice 

Interesting. I wonder if some other part of the brain kicks in once we exhaust the possibilities dictated by reason.

I agree that in my case, I probably would never had discovered the root of the problem had I not happened to demo speakers with taller cabinets. I would've gone on to exploring power conditioners and perhaps given up entirely on vocal music... 

I was just lucky, I guess. 

Ok, well congratulations! But, I can’t imagining finding that but to stumble on it.

It is interesting. I realized, that I will usually only put so much effort (quite a bit) into solving a problem. Then just go on. Typically, I’ll do something unexpected and discover the real cause of the problem. I realize I developed this largely unconscious method over decades of problem solving… you just made me conscious of it. Thanks.