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Romy the Cat wrote:

I figure out that it is time and put some acoustic treatment on the walls and at some spot of ceiling. The 2” pyramids in white, 24” by 24” look very nice; in fact they almost work like abstract yuppie-ornamentation popular in some Manhattan lofts - not exactly my style but I care less. All together I put 11 sheets of the foam over the entire room and removed all fiberglass traps. I left only 8 ACS fiberglass panel on the ridge of cathedral ceiling. The result was as expected: the room becomes much quitter, sound got less zippy and with less harsh noise, the high amplitude of paling does not overload the room, I might run tweeters harder and the HF ringing on the room not there anymore. That all is fine and they all very positive moments, however I would not say that I this new the Sound all together. I have very difficult time to define what I do like. This new sound got some upper MF efforts in itself that I did not have before when the room was “live”. That effect of heavy laboring in upper range a bit annoying and also it makes wonderful and impressive audio but this is not the result that I am interested in. I very much like the control over HF but I would like do not prevent them to be as they are, I do not want to over manage them. It is not that my room is over-damped now. I think it is OK balance as I cover very few spots with foam- 11 sheet of 24” by 24” is nothing for this room. Still, the contribution of the foam is very profound and not only positive. There is also a sense of artificial hyper-resolution that I very much do not like and it came with the use of foam. The fiberglass on tube traps gave me thin sound, foam gave me flawed resolution. Both are wrong in my view. Surely it is too early to make any conclusion as I only started to play with it. In my old room the “acoustic treatment” was made stuck of record shelves – that worked phenomenally well and it was in a way a natural a natural treatment. Now I use artificial treatment that does not exist in nature. Might it be one of the reasons? If so, then will I have better sound if I order green panels? Anyhow, I look forward to experiment more with acoustic treatment. The result I got now I find not acceptable.

Today I was thinking all day long what the hell is happening in my room and why the 2” pyramids do the job to subdue HF in my room but still create problem and kill Sound. The ease and spontaneity of Sound the I had just two day back is gone and replaced with labored pressure and not at the high frequency but in upper mid range.  I was thinking listening, changing a lot today in acoustic treatment, even put the large black panels back – nothing worked – the right sound has gone. I played good 5 hours with it and twice fallen from my step ladder – the only think the work properly in my room was gravity…

I do not want to give an impression that I love to do all of it too much but I was very pissed as there was some kind of hidden reason WHY it happened and I knew that until I get control over this reason I will not get my Sound in my room. If it was 2 years back then I would blame electricity but now I PP2000 my entire system and I am accustomed that sound does not changed from day to day.

I said that I give up and started to do absolutely idiotic think – I began to move the thing into my room exactly as it was 3 days back, when I make my post “I’m drinking from the grail of glory.” Then I turn the CD. From the very first note I know that I have my sound back, I was laughing like a meshugana!

Then I begin to analyze what was change. The biggest thing was that I put the fiberglass tube traps back into the room. They are very powerful at HF but NOT so powerful to moderate the MF pressure. Then it came to! As anything else it was ridicules simple and surprisingly you.

A couple, years back a site reader from Swaziland contacted me and share an interesting idea of shaping sound with reflective panels. We spoke over the phone and I made some experiments building his panels. It was interesting but no more than that. Suddenly during my straggling with Acoustic Treatment I felt that I experience the same “MF pressure” and my Swaziland managed with his reflectors. I looked at the well-treated with foam 24” wide wall behind my listening chair  that cover the load-caring beams - now it was covered with 20” fiberglass half-tubes. It stroked me that it is not about the fiberglass vs. foam but about the shape of this wall. Even covering with foam the wall is not reflective at HF but at MF it acts as the Swaziland reflector. Since the wall is very much stand alone and has my listening position has no back reelections (something that I was craving for years!!!!) the harrow wall was acting like a lens, focusing the only back reflection to my chair. Looking at the size of the wall 22” and the double distance from the wall to the chair it was obvious where the MF pressure came from.  In case of the fiberglass half-tubes the wall was converted into a sphere with no ability to focus the reflection back to me.

That explained everything, including why I felt that the fiberglass tubes had so powerful effect in my room. I immediately took aluminum foil and warped it around the half-tubes behind the chair. The great sound did not despair. So, it was NOT about absorption rate about reflective shape! I am a fucking genius!

Now I had good sound and full control over it.  I was inspired. I took my foam back but kept the half-tubes behind the chair’s wall. I realized that I do not want to kill HF anymore and want to randomize HF making room live but controlled live. I left the foam only on the very few strategic locations and took the rest foam away. Then I took 6” spikes and covered with them the top of the back wall, still keeping the half-tubes on the back wall behind the chair. The Sound was very nice, room feel very nice and I feel that it is it about acoustic treatment. The only thing I need now is to get my custom made 30 pounds air-condition ducts and to replace the 20” fiberglass half-tubes with 24” half-tubes (will less extend into room), covering the half-tubes with nice fabric. Below are a few pictures how the acoustic treatment is use in my room as now.

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