With exception to the fact that I have no bass my new room did not give me a lot that I feel might be qualified as strange. I still do not know this room as good as I knew my old room but I will be there, it is a derivative of time. It is not that I do not “have” bass in the new room – I do not connect bass. My woofer towers are sitting in the next room, not connected. I do feel that it is possible to make them to work properly in context of this room but it would take a LOT of efforts to take care about more powerful amplification and going for complicated filtration to deal with the room bass idiosyncrasies.  Since the midbass horn will override all those efforts I decided do not do anything with LF channels unit the midbass will be installed, measured and calibrated. So, I completely intentionally do not use any bass at all.

Still, I did not say that my new room did not give me anything that I feel might be qualified as strange but I said that my room did not give me a lot that I feel might be qualified as strange. It means that there is something that I do not “get” now, exactly two moments that I absolutely do not have any explanation. I mention them before but now I would like highlight them.

1)      I do not know what is going on with lower knee of my Injection Chanel. In the old room the lower part of Injection worked phenomenally well. In the new room the same Injection by the same amplification do clearly portrays that the bottom part of Injection not up-to par with the rest system. In old room I closed it at 110Hz not I drive it full range. Is the bottom of the Tannoy Red is so bad? Interesting that in old room the 110Hz were more auditable then a full range in the new room, Since it all 12-13dB UNDER the referent volume level I wonder why the  Red’s bass is so much in my face now.  Were the bass in old room provided some sort of masking effect that glazed the Red’s bottom? I do not know but I would like to find any answer and it has a few consequences for Macondo configuration.

2)      The second mystery is something that made me dumbfounded. All the Macondo has at bottom is 35 inch horn. Let see, 35” = 89.8cm.  115Hz crossover point is 82cm, 110Hz crossover point is 88cm and 105Hz crossover point is 95cm. So, my upperbass horn is about 107Hz anechoicly. In the old room it was running down to 95Hz, in the new room, sitting virtually in the mid of the room it hits 140Hz. Also, it is a sealed, full tractrix, so it does not have that glowing long boom at bottom and it rolls off very fast. So, my playback has nothing under 140Hz – it shell not sound acceptable.  I am well familiar with the Macondo just with upperbass and it was in the room when upperbass was going down to 95Hz. It was NEVER sufficient. Now, in the new room it is not just sufficient140Hz but it is truly spectacular. I have been listening like like this for 2-3 weeks and sometimes I forget that I have no bass. The sound is surprisingly rich. Still, the RTA does not lie and I DO NOT have the any bass. If so, then why it sound so good and non-problematic with this absolutely surprising new level of upperbass quality?

jessie.dazzle wrote:

About the blinds you have: Amazing; they inspire suicide!

I found a company here in Boston that sell a lot of industrial things including a lot of acoustic material

http://www.kamcoboston.com/Products/default.asp

http://www.kamcoboston.com/Products/categoryView.asp?CategoryID=20

Funny but they are a mile away from my home… I think I will be using them as the do have a lot of selection, much more then audio companies do. Also, these prices are a bit better…

Romy the Cat wrote:

I found a company here in Boston that sell a lot of industrial things including a lot of acoustic material http://www.kamcoboston.com/Products/default.asp http://www.kamcoboston.com/Products/categoryView.asp?CategoryID=20 Funny but they are a mile away from my home… I think I will be using them as the do have a lot of selection, much more then audio companies do. Also, these prices are a bit better… The Cat

Serge wrote:

2. Can you write once again what are the problems in your room which need to be solved acoustically.

Serge wrote:

I will think about it. Romy, of course you know me. Use your little grey cells as Msr Poirot used to say. Initial thoughts: hunting HF reflections and damping them is generally not a good idea. It is like making a speaker cabinet completely damped - the life in the sound goes away with the resonances. There should be reflections, but random and low in amplitude. So to begin with let's think not how to make the room absorb HF but how to make it scatter them in a good manner. Quite unexpectedly wooden things are most effective there and not man made stuff. Probably you need to wait till the finishing is finished and furniture is there. And again: in no way I am giving advice, I'd rather see a discussion.

Romy the Cat wrote:

The only thing that I do not have is some kind of stand alone, mid room HF eater that I would like to place between speakers and the back wall’s windows, something like tube traps or the similar. I do not like the tube traps but they are less ugly than any other similar treatment. Also, tube traps are ridiculously expensive. I need 12”-15” wide and 8-9 feet long. The tube traps of these dimensions are around $2.5K. Sorry, but this is just a piece of fabric covering a fiberglass pipe. The fiberglass pipes everyone buy from the same Knauf factory and it costs virtually nothing. The piece of fabric starch above it is also cost a few dollars, so why the $2.5K price tag? Because the dealers who sell all this crap need to pay their mortgagees? I do not know, to feed those leeches does not sound too attractive to me. The Cat

Romy the Cat wrote:

this is just a piece of fabric covering a fiberglass pipe. The fiberglass pipes everyone buy from the same Knauf factory and it costs virtually nothing. The piece of fabric starch above it is also cost a few dollars, so why the $2.5K price tag? Because the dealers who sell all this crap need to pay their mortgagees? I do not know, to feed those leeches does not sound too attractive to me. The Cat

Serge wrote:

Wouldn't you want to try some HF diffusing stuff on your back wall windows? Like wooden plank blinds if you see what I mean? Or you want the reflections to be catched earlier, behind the listening couch?

Nope, it will be no HF diffusing on your back wall windows; at least I am not planning to do it now. I have different idea. In fact I had this ide from the very first time what I saw the room during the open house. I do not have a newest picture, use the old one:

If you look at the picture then you see power entry port in the carpet in the middle of the room, between the pile of carpenter shit under cloth and the brash. This power entry is presumed listening position. So, what is behind, what would constitute a back wall? The vertical column in near mid of the room, which is 22”, and the ridge under the horns. The rest space is wide open and reflections form this wide open spaces are high but they are very far and very low in amplitude. So, whatever is left from the back wall – horizontal ridge, middle vertical column and those two narrow side vertical columns will be covered with 2” pyramid white melamine foam. The 2” is not too deadly foam acoustically and not too extended in the room. It looks also not so bad that is important to me. I am convinced that the amount “treated” surface on the back wall in proportion to wide open untreated space will do fine and will not over damp the back wall.  It will be 4-6 “islands” however on the ridge made from 6” foam, I will use them to will break the monotonous reflective patter of the 2” pyramid. I have bought everything already and it sitting in the next room, waiting to be used. What I palace all of it on wall wall I will make a picture that will show what I meant to do. Also, as I put the things to the walls I will be listening and will be able see how it goes.

To my big surprise, the biggest in subject to me in room treatment now is not the room treatment itself but finalizing the exact location of listening chair.  It feels like a large room and the chair might slide a good 8 feet closer and further from the speakers. In reality however it will be just ONE very virtually bolted location for my chair. To finalize the deadly location for listening chair is a bit tricky but everything I will do with playback will start ONLY AFTER this location is found. The right location would imply the Macondo upperbass and upper channel arrival calibration, midbass arrival and ULF arrival. Remind you that time alignment is a subject of crossover order, each order is ~ 2.5’ at 100Hz. So, I need to get precisely how my channels are operating, have them properly calibrated and then to find the only proper arrival equidistant position. Do not forget then in my room the MF, upperbass and lower bass will arrive from 3 different directions – front, back, and above. So, the location of my listening chair will be VERY important in order to make everything to work as I would like it to work.  My current experiments, to me displeasure, suggest that the listening chair will be much closer to the back way then I initially thought. Still, this is not final location and I am working on this subject now.

Unicon, I did research the topic of the tube traps and I will make them myself. Partially it is money and partially because I would like them to be exactly as I wanted them to be. I have a local company:

http://www.generalinsulation.com/

…a few towns over in Malden the sell the compress fiberglass tubes, $3-$4 per foot.

The fabric to cover the tube is not a big deal at all.

http://www.fabricmatestore.com/p-9-fr701-panel-fabric.aspx

Even if I do not do it myself (that shall be very easy) and recruit my carpenter to do it for me then I will be hugely less expensive but I will have the tubes exactly as I want them to be. I do need some middle of the room absorbers and HF stoppers. I would like to use the room with my glass door’s shades wide opened but during the cold times I will not be able to open the glass doors. To listen with glass is imposable, so I need to fun some kind of treatment that would allow me to have glass door closed but with the blinds. BTW, the women who sold me the house told me that during the winter the conservation land behind my glass doors will be endless white file with hills, sort of a Vermont landscape.  I can’t wait to see it, to fire my fireplace and play the second movement from Rachmaninoff’s Second Concerto….

Serge, this is ironic that you make this port. Last night a friend of mine discussed exactly the subject of what alternately might be done with the vertical column and the horizontal ridge behind the listening chair.  The column and the ridge are the only direct reflectors and they need to be treated with extreme prejudice. My initial sentiment to cover them with white pyramid foam stands I however look also at alternatives. I have separate 2 reasons to look at alternatives. For the column I feel that white foam might not fork for a long run as the white melamine foam is extremely susceptive to dirt. It is enough for a person to walk once between chair and the foam on column and to touch the foam as the white foam become not white anymore. A vertical column what foam above is white but below is gray will not look/feel so pleasant. And the reason for the ridge – there is no space limit in there and I feel that I can do more attractive then juts foam covering.

The concern I have is not about reasons but about column. My listening chair might end up in a final position a bit closer to the back column then I initially thought. If so then the diffuser in there might not work and it needs some reflective space to be effective. So, the semi- diffusing foam might be the only options. A month or so ago I have cut around 400 1x1 sticks trying to render the idea or RPG Skyline

http://www.rpginc.com/products/skyline/index.htm

They were from 1” to 5” sticks and I changed the design by introduction 45 degrees and 30 degrees cuts in the end of each stick, the cuts to random directions. I call this design the “Circumcised Skyline”. I have them sitting in garbage bag somewhere in basement – I might try to employ them on the column as they are very hard diffusers. I just need to visualize how it will look like – I do not want the wall cover to look like it “too much trying”, if you know what I mean.

For the ridge I am very open to idea. The ridge might be anything diffusive and if I have an elegant idea how to make the diffuser then I would go for it. I do not mean “how to make” from point of construction but rather form a point of design. The sample that you posted I do not like. I would like it to be more airy, more extended into the room and to be more futuristic by appeal. Last night talking to a friend of my I called the concept “Extended Birds Nest” – of some kind randomizer but extended from the wall toward the mid of the room – a feet will be fine.  Here is what I illustrated the concept but it for she need some artistic supervision.

 

The inspiration came of from here:

The Cat