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Supreme Home Theater Hall - Where Decor Meets Acoustics - Page 3

post #61 of 80
Quote:
Originally Posted by blazar View Post

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

this is the site with the diffusion graphs for the material that I used on the doors. Do you think this would be bad behind the listening position necessarily?

im merely trying to draw attention to the fact that sound has size and diffusers need to be of certain physical size to be 'seen' by relevant wavelengths.

i would not recommend spending large sums of time and money on "diffusers" that are only seen by HF wavelengths of which have little energy content to begin with. in the case of QRDs (like what appears to be N7 QRDs on your door), the wells are so shallow that the diffusers on the door are not going to be "seen" by any relevant mid-band energies! no diffusion will take place - those wavelengths will not see the highly complex well pattern on the door...they will simply see and reflect as if the door were a flat boundary.

again, i would seriously consider taking a brief moment and read the QRDude technical guide. even if you are not building Schroeder diffusers based on Quadratic Residue number theory, it helps to understand some of the foundations for such devices.

if you want to see a room with true "diffusion everywhere" - i suggest investigating the Ambechoic acoustic model of Blackbird Studio C (http://www.google.com/search?tbm=isc...l939l1.5.1l7l0)

you'll notice how deep the diffusers are in this extreme example, as sound has size and the diffusers need to be of sufficient physical dimensions in order to properly diffuse such low-mid frequencies. it may also shine some light onto those who think "diffusion everywhere" may create too live of a room - as the first order reflections are attenuated by the diffusers by -30dB!

if you're really interested in diffusion everywhere within your room, it may be wise to take the time to understand how "diffusers" actually diffuse (temporal and spatial dispersion) sound, the limitations, design constraints, and the relevant physical dimensions that must be adhered to in order to meet your design criteria.

regarding polys, which can be useful in larger (relative) home rooms (and more affordable), there really is much design work that needs to be taking into consideration. some additional insight:
http://www.gearslutz.com/board/studi...er-thread.html
http://www.gearslutz.com/board/studi...ion-polys.html
http://www.gearslutz.com/board/bass-...i-y-polys.html
http://www.gearslutz.com/board/studi...er-design.html
post #62 of 80
http://www.rpginc.com/news/library/tyndall_paper.pdf
post #63 of 80
Thread Starter 
Quote:

I did read the articles you posted and I do understand that the situation is very "complex". This is exactly why I built the room in such a way that nothing is necessarily permanent in terms of room treatments.

There is no inherent guarantee that any design by any designer will necessarily sound perfect. In fact, I'm not really sure there is such a thing as perfect. I literally guessed at some of the surfaces based on pictures from various acoustics websites.

Having been through a ridiculous amount of acoustics articles, forums, user comments, pictures, acoustic products websites, etc... I have come to the conclusion that there are no absolutes. I have seen articles about diffusion behind the listening position that recommend it and others that do not (for example). Sitting too close to some types of diffusers make them not function properly as well. There is no way in the universe I was going to know what exact diffusers would work best, what scale they should be built in, or how it would affect specific listeners in the room.

I knew going into this that I was almost certain to like the sound of an arbitrarily arranged diffusive room with plenty of bass traps compared to a simple rectangular room. I certainly don't like an echo room and I definitely don't like a dead room either. Something in between albeit imperfect ... is ok by me.

I also knew that I wasn't going to get enough of an interesting room architecturally if I simply went with a "home theater designer". Since the room is somewhat modular, I can actually take out the hemifusers and do QRD's or something else based on future budgets for modifications.

There is simply no mathematical computer in the world that is going to accurately model what the diffusion/absorption characteristics are going to be until I get the whole thing running and test it in reality. There are SO many bumpy surfaces and trim of different sizes all over the room. The ceiling is not flat either. Once the furniture/rug/people are added in, there will of course be additional absorption.

Like you said, some of the diffusers may actually demonstrate various levels of absorption. Who can really say in such a complex room what the final results are going to be? As a person with reasonable scientific degrees... I know that there are enough variables in this equation to make "perfection" unknowable a-priori. I'm just going to listen to the whole mess and pray it comes together the first time... If not, time to play with the treatment arrangement a bit with the help of some acoustic measurements.

So far, spoken words in the room sound extremely clear with a very "live" sound without any hint of echo. The noise floor in the room is very low also but I don't have the proper equipment to test the actual numbers yet. Based on my current home as reference (~20db), I would estimate about 15db of ambient noise. With the AC off and when there is no wind outside, It may be closer to 10db noise floor.

Part of the room that is not done yet is the stone on the wall around the base of the room. Each piece of stone will be bumpy and will actually be placed at different depths just like the outside of my house. This will add additional differences in acoustics.

I would imagine that most people simply do not put in this much diffusion and architectural surfaces to really know one way or another how it might sound. It's certainly a fun experiment for me and I will certainly report back if the whole thing sounds like a mess or what.
post #64 of 80
Thread Starter 
here are some pictures with most lighting fixtures completed.
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post #65 of 80
Quote:
Originally Posted by blazar View Post

I did read the articles you posted and I do understand that the situation is very "complex". This is exactly why I built the room in such a way that nothing is necessarily permanent in terms of room treatments.

There is no inherent guarantee that any design by any designer will necessarily sound perfect.

nothing was said about "sounding perfect" - i was merely pointing out that sound has size and any object/surface you are wishing to use as a 'diffuser' needs to be large in relationship to the frequencies you are interested in diffusing - which is normally mid-band. also note the difference between a device that scatters energy vs a true diffuser that spatially disperses energy as evenly as possible in all directions in the hemisphere regardless of angle of incidence.

the N7 QRD patterns on your door; what is the max depth of the well?

Quote:
Originally Posted by blazar View Post

Sitting too close to some types of diffusers make them not function properly as well.

depends on the type of 'diffuser'. phase grating diffusers based on Schroeder number theory (quadratic residue or primitive root sequences, QRD/PRDs respectively), 3x the design frequency is generally recommended - sitting too close is like sitting in the near-field of a multi-way speaker (that is not designed for near-field) where the coherent return field has not fully developed.

examples via Ripple Tank:
http://vimeo.com/6461707
http://vimeo.com/7507997

notice as frequency increases and the lobes begin to develope - look at the complex, chaotic interference pattern at the outer face of the wells - versus in the far-field where the coherent diffuse-field return has developed.


Quote:
Originally Posted by blazar View Post

Part of the room that is not done yet is the stone on the wall around the base of the room. Each piece of stone will be bumpy and will actually be placed at different depths just like the outside of my house. This will add additional differences in acoustics.

what is the size of these depths? again, my commentary is only to bring attention to the fact that sound has size - and such relatively small changes in surface will only be seen by very high freq content of which isn't very relevant to "diffuse" as other bands which contain inherently more energy content.

Quote:
Originally Posted by blazar View Post

I would imagine that most people simply do not put in this much diffusion and architectural surfaces to really know one way or another how it might sound. It's certainly a fun experiment for me and I will certainly report back if the whole thing sounds like a mess or what.

the issue is when covering large surface areas with "diffusers", of which to achieve the proper surface area, many repeated diffusers are used which can have a negative effect on the overall response of the array. example: Schroeder QRDs should not be used stand-alone (eg, one QRD by itself) unless the prime number used is very very high. periodicity is required for QRD interference pattern to generate the equal energy lobes, but too much periodicity will result in these lobes becoming very narrow and very high in gain - thus we utilize Inverse QRD diffusers and adhere to the Barker Code (http://en.wikipedia.org/wiki/Barker_code) to maintain even response.

AFMG Reflex is available for free, 30-day trial if you are interested in seeing the polar responses and scattering/diffusing coefficients of such surfaces (especially important when large coverages of repeated surfaces are used).

http://reflex.afmg.eu/index.php/rf-features-en.html

again, im not saying anything is wrong - but just calling to attention to some of the underlying principles of diffusers such that they can be designed and utilized accordingly.
post #66 of 80
Thread Starter 
Cool i am keeping track of all the refernces, great info.
post #67 of 80
Thread Starter 
Ok I listened to the folks here that have said that a standard 1" dome tweeter based speaker was not going to fill this room with appropriate frequency response.

Here is what I just installed:

AvantGarde DUO Omega for mains
AvantGarde SOLO for center
Pass Labs Class A XA30.5 Stereo Amplifier

So far I haven't gotten the Audyssey pre-amp that I need since I am hoping to get the next Denon Flagship with XLR outputs with 11.2 if such a thing ever exists.

The sound so far: STUNNING. The Room sounds right without even doing anything else as far as room correction. The speakers image amazing so far. I am using a old Carver pre-amp and airport express as the dac (both junk with too much hiss). Eventually I will supplant this junk with a proper pre-amp with a good dac. I have been trying to get one component at a time completed.

Once I have the analysis software setup with my mic, I will be able to do room analysis. At this point I will mainly want to equalize the bass of my in-wal subs and adjust the sub in the avant-garde DUO correctly.

A lot more work to do, but pictures of the completed work to follow soon.
post #68 of 80
bazar -
just found your thread and read through. great looking room; I'm a fan of the woodwork and architectural details. You mentioned in wall subs. I didn't see pics of those. Where are those hiding?
Looking forward to updates!
post #69 of 80
Thread Starter 
updated images... getting close to completion
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post #70 of 80
Thread Starter 
couple more...
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post #71 of 80
Thread Starter 
BG Radia subs are in those niches on the sides of the room (1 in each corner of the room). I should have taken a specific picture of one installed.

Here is a picture of the subs attached with their amp (which is on my rack in the closet).
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post #72 of 80
Thread Starter 
I plugged my mac mini (without a dedicated DAC), directly into my Pass Labs amplifier.... and I am amazed with the results.

The imaging is perfectly centered now and the imaging is nothing short of holographic. Like no other system or room I have heard in my life so far. These speakers are really something to love when setup correctly in the right room.

The BG Radia subwoofers are extremely musical and totally transparent (not noticeable).

The room has NO audible vibrations from the bass so far.

The two stage air conditioner in the room really makes air conditioning inaudible in here.

I still haven't purchased a receiver with Audyssey 11.2 or 9.2 so I cannot yet comment on the integration of the Avantgarde SOLO center channel speaker.

I have ordered an Epson Powerlite 5010 projector which should be exciting to try out.

Control4 is now powering the lights, Lutron shades for the windows, and the 159" Vutec movie screen.
post #73 of 80
Quote:
Originally Posted by blazar View Post

...I have ordered an Epson Powerlite 5010 projector which should be exciting to try out.

With such a room and speakers, i was surprised with the PJ choice. I would have pegged this room powering a Runco, Sim2 or Digital Projection Titan level of PJ. What drove you to this choice (since it's one that I'm thinking about along w/ the Panny 7k)?

room still has wow factor in the woodworking and details for me!
post #74 of 80
Thread Starter 
Quote:
Originally Posted by misugrad View Post


With such a room and speakers, i was surprised with the PJ choice. I would have pegged this room powering a Runco, Sim2 or Digital Projection Titan level of PJ. What drove you to this choice (since it's one that I'm thinking about along w/ the Panny 7k)?

room still has wow factor in the woodworking and details for me!

Well basically i am broke now... And this is a good bang for buck unit that will suffice for a few years. Projectors improve so fast anyway and today's runco is tomorrow's epson. The room was more for music anyway.
post #75 of 80
Thread Starter 
Equipment Update:

Crown XLS 2000 amplifiers. These are very reasonably priced amplification which I believe use Texas Instruments "Class D" chips. These are practically limitless power for 4 ohm BG Radia speakers. They sound great so far and I don't know of any major limitations while listening. The basic review is that they sound great and are WAY more than powerful enough for this big theater room. I LOVE the SPEAKON connectors (I am using 4 post speakons). I am even going to change my wall plates from banana plugs to speakon just because they are SO GREAT! I wish all speakers and amps had Speakon connectors. The spades on the Pass Labs amp look cheap in comparison.

Integra DHC 80.3 with Audyssey DSX processing. I am doing 9.1 with heights and wides up front. For the rear speakers I cheated and used the rear side speaker channels to also power the surround back speakers since the INTEGRA Does not do 11.2 which my speakers are setup for. The unit is otherwise great and does just about everything I need it to do and almost everything i ever wished a pre-amp could do. I can preset all stereo listening on every input to Audyssey 2 channel and all surround sound on every input to Audyssey DSX. I will never change to other surround modes since these are clearly the best. What is great is that you can setup what will happen for 2 channel vs multichannel on EACH input and these settings will be saved. Thusfar, 2 channel audio sounds fantastic with or without equalization. I used -10dB XLR "Pad" adapters into the amplifier for the main channels since the receiver can't set the volume automatically for these speakers since they are too sensitive.

I also ordered a Furman P-2400 IT (their top of the line PRO power conditioner). I am not a huge believer in this stuff however the horns are SO revealing of minor noise that I figured what the heck, lets try some "balanced power". Lot of good reviews about the positive effects of these types of units. I really only care about whether or not it will improve stereo listening with the Pass Labs XA30.5 amplifier.

Epson Powerlite 5010 projector - was nervous about having a bright enough projector for our long 23' throw distance but this was unfounded. The brightness is just right and I am generally able to use cinema mode with auto iris off and it looks great. It is also a quiet projector when used in "eco" mode so I didn't really need the extra brightness of full power or addition "dynamic" color mode. The only annoying thing on this projector is boot time, but this is a minor quip.

The room thus far at reference 0db sounds EXCELLENT. I haven't done all the EQ curves yet but those should be forthcoming in the future.
post #76 of 80
Is that the final finish on the timber work?

Interested to see the measurement plots when you're ready
post #77 of 80
Thread Starter 
Quote:
Originally Posted by Elill View Post

Is that the final finish on the timber work?

Interested to see the measurement plots when you're ready

Yes the color is a arctic white with brown glaze on top. Very unique looking color I think.
post #78 of 80
Thread Starter 
Some new observations: various objects in the room started vibrating at their resonant frequencies. Have been working these out to eliminate vibration as much as possible.

Did frequency analysis extensively and despite all 4 subs there is a null at 65hz. Also the 20hz to 40hz range is not good enough still. Thinking of dropping a pair of JL fathom behind each main speaker and cross them over high at 120 to add some real punch to music while getting the added low bass 20-40hz response.
post #79 of 80
Thread Starter 
Forgot to mention i added two more crown xls amps for new clark synthesis platinum bass shakers which blend in great
post #80 of 80
Thread Starter 
well just ordered a pair of JL Audio Fathom 212 subs..... these "should" do the trick... should peel the paint from the walls.

Will place them with the main speakers +/- positioning needed to erase any nulls. Will relegate the BG radia subs to the duty of evening out any nulls from the Fathoms in the range of 50-80hz.

If I had it all to do again, I would have made more space for fathoms from the beginning but everything will be "ok"!
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