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post #61 of 148 Old 01-27-2011, 08:21 AM - Thread Starter
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Originally Posted by carboranadum View Post

Here's another data point. My front row is 138" from my 130" wide 2.38:1 screen. My second row is 216" from the screen. My ratios are:

Front row: 1.06
Back row: 1.66

Sitting in the front row is really intense for 2.35 content. I like it! I normally sit in the back row for 2.35 content and the front for 16:9. My kids, however, LOVE the front row for everything!

I see you use a Panny4000. Do you use Cinema mode? If so, you'd be getting about 9 ft-lamberts. Is that bright enough? Thanks
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post #62 of 148 Old 01-27-2011, 03:47 PM
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Ted,
It's great to hear from you! It's been over 3 years since I finished my theater and basement and I can't tell you how much I am still THRILLED with my soundproofing efforts and the advice that you provided. As you know, I not only soundproofed my theater but my entire basement with the "room-in-room/isolation clips/greenglue/double drywall" method. It is fantastic! Thanks again for all you help, advice, and your amazing products.

DIY,
Your measurements sound pretty good. I used double studs for my false wall, but that was probably overkill. Single studs will probably be fine; just be sure to use lumber that won't warp. Standard studs can warp terribly over time if left untreated with no drywall face.

I have 24" doors on each side, but 18" would be fine as long as you can get all of your equipment/speakers behind the wall. You are right that the doors are rarely used once everything is set up.

I actually have about 7" between my doors and the screen opening rather than 5" but I think you could make 5" work. I just looked at my side masking and it would all fit within 5", so I think you'll be fine.

For the height of your screen off the floor, I believe the primary issue will be the viewing angle from your second row. I think there is still a riser height calculator somewhere here on the forum. Just be sure the bottom of your screen is visible from the second row when looking over people seated in the first row. My screen is 22" from the floor, but I don't have a second row riser.

My screen does not have any border attached to the screen itself. My masking provides the entire screen border. Because of this, I always have a little bit of masking overlapping all edges of the screen (at least 1"). I say this because the actual viewable area of the screen is slightly less than the full screen size. For example, if you want a finished viewable area of 163" x 68", you might want the screen to be 165" X 70" (which is not not a 2.40 ratio, but with the masking all the way around it becomes a 2.40 viewable screen). -- Just something to consider as you are designing the false wall and ordering the screen.

- Scott
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post #63 of 148 Old 01-27-2011, 04:04 PM - Thread Starter
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Quote:
Originally Posted by ScottJ0007 View Post

Ted,
It's great to hear from you! It's been over 3 years since I finished my theater and basement and I can't tell you how much I am still THRILLED with my soundproofing efforts and the advice that you provided. As you know, I not only soundproofed my theater but my entire basement with the "room-in-room/isolation clips/greenglue/double drywall" method. It is fantastic! Thanks again for all you help, advice, and your amazing products.

DIY,
Your measurements sound pretty good. I used double studs for my false wall, but that was probably overkill. Single studs will probably be fine; just be sure to use lumber that won't warp. Standard studs can warp terribly over time if left untreated with no drywall face.

I have 24" doors on each side, but 18" would be fine as long as you can get all of your equipment/speakers behind the wall. You are right that the doors are rarely used once everything is set up.

I actually have about 7" between my doors and the screen opening rather than 5" but I think you could make 5" work. I just looked at my side masking and it would all fit within 5", so I think you'll be fine.

For the height of your screen off the floor, I believe the primary issue will be the viewing angle from your second row. I think there is still a riser height calculator somewhere here on the forum. Just be sure the bottom of your screen is visible from the second row when looking over people seated in the first row. My screen is 22" from the floor, but I don't have a second row riser.

My screen does not have any border attached to the screen itself. My masking provides the entire screen border. Because of this, I always have a little bit of masking overlapping all edges of the screen (at least 1"). I say this because the actual viewable area of the screen is slightly less than the full screen size. For example, if you want a finished viewable area of 163" x 68", you might want the screen to be 165" X 70" (which is not not a 2.40 ratio, but with the masking all the way around it becomes a 2.40 viewable screen). -- Just something to consider as you are designing the false wall and ordering the screen.

- Scott

Scott:
Thanks for confirming the dimensions. I might use metal studs for the false wall to minimize risk of warping. I am glad that your soundproofing worked great. I used the techniques provided by The Soundproofing Company. Hopefully, mine works just as well. For gang boxes, I used putty pads. I have quite a few for switches, outlets, and low voltage drops. I don't know how much sound will leak through those openings.
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post #64 of 148 Old 01-27-2011, 05:10 PM
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Quote:
Originally Posted by DIYHomeTheater View Post

Using BenQ W6000 in a light controlled room, that is capable of 1050 calibrated lumens, the screen brightness at 1.1 gain (conservative) will be = 15 ft. lamberts.

You might want to check out umr's screen materials tests in the Screens forum. Actual gain of Seymour XD material is a lot less than that.
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post #65 of 148 Old 01-27-2011, 05:52 PM - Thread Starter
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Rader:

Checked out UMR's report. Observed gain is 21% less than published claim. So, effectively, it is 0.95. All else being the same, for 2.40 content, my screen brightness now will be down to 13 foot-lamberts, ie below THX standard (16) but a shade higher than SMPTE (12). Good to know. I'll have to use masking to reduce the screen size for 2.40 content. For 16:9 content, my brightness should be good enough at 17.6. On the positive side, he does think that XD is a good material at over 11' viewing distances. Thanks for pointing to UMR's results. For those who are interested in UMR's report, it is available here
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post #66 of 148 Old 01-27-2011, 06:38 PM
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That's the nice thing about making a screen bigger than what you need. You can always mask down to preference and projector limitations. A lot easier that making a too small screen bigger.
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post #67 of 148 Old 01-31-2011, 04:48 AM
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DIYHT,

Just like you, I knew little to nothing before I started the design of my (multipurpose) HT and want a BIG screen. In our current living room, we watch TV and Blu-rays on a 65" RPTV at about 100" distance. Coming from a 26" old TV, it took some getting used to the size. About 3 days anyway... Now we think this is way to small for 2,35/1 content.

So, I went way over the top and designed a 175" diagonal widescreen from less than 150" distance... Several experts found that unwise and to much. So we went to see Tron: Legacy 3D in a commercial theater and I took my tape measure with me! Seats were numbered, so it turned out we were at 22.5 m and the screen width was 20 m. My assessment is that this was by no means to close a distance. I am certain that 20 m would have been ideal! We shall go back another time since I now know where to book to be at 20 m. Fast+Furious 5 is on the horizon...

20 m distance for 20 m screen width is about 50°. I changed the design to a 144" diagonal (W about 11') and a 11' distance, the closest recommended for Centerstage AT fabric (I will probably get the center behind it, but not the L+R)

I also have the BenQ W6000 on my list, but this will be the W7000 by the time the build is ready, LOL! BenQ is also €500 cheaper in EU than Panasonic 4000, unlike USA.

Attached floor plan attempt #8
Attachment 200175

One more thing: Ethan Winer suggests a the best spot for the ears is at 38% from the front wall. If that's not practical, 38% from the back wall is second best.

 

Ronse2010B_HTplan8.pdf 498.1220703125k . file

Building a HT with 7.2.4 layout and ◤SEOS-24◥ LCR.
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post #68 of 148 Old 01-31-2011, 05:19 AM - Thread Starter
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Quote:
Originally Posted by erwinfrombelgium View Post

DIYHT,

So, I went way over the top and designed a 175" diagonal widescreen from less than 150" distance... Several experts found that unwise and to much.

20 m distance for 20 m screen width is about 50°. I changed the design to a 144" diagonal (W about 11') and a 11' distance, the closest recommended for Centerstage AT fabric (I will probably get the center behind it, but not the L+R)

Erwin:
If you sit any closer (say 107") you will start seeing the individual pixels on 1080P content. Of course, the angle may be unbearable at that range. Your field of view for an 11'W screen from 11' seating is actually 53 degrees. For a 175"W screen from 150" would be 60.5 degrees. Yes, that's wide.

Many people on this thread have reported no problems with 48 degrees (and some even wider).

You can check out Carlton Bale's calculator on the Web for these calculations.
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post #69 of 148 Old 02-09-2011, 09:25 AM
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DIY and I had a PM discussion, and I thought I'd chime in here on the thread. My 2.35 screen is 168" in width. Front row at 144", Middle row at 228" and rear bar at 300". I use a Panny AE4000.

My primary seating is in the middle row at 1.6 x screen width is comfortable for everyone. The front row (1.16 x screen width) is only used with big crowds or people that like it big. I choose the middle row, but don't hesitate to sit in the front.

No disrespect to all of the professional guidelines and such, but they are just that, guidelines. I think you can go with your suggested screen size and not look back. You'll forget about all of the math when the lights go down and the movie starts.

I do agree with others that I would get three rows in the room. Slide the current two forward and put a bar in the rear. The bar is without question the most used spot in our room!

The "Twinseltown" Theater
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post #70 of 148 Old 02-09-2011, 09:28 AM - Thread Starter
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Quote:
Originally Posted by tony123 View Post
No disrespect to all of the professional guidelines and such, but they are just that, guidelines. I think you can go with your suggested screen size and not look back. You'll forget about all of the math when the lights go down and the movie starts.
Tony:
That's just the kind of end user endorsement that I was waiting to hear! Thank you.
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post #71 of 148 Old 02-10-2011, 06:23 AM - Thread Starter
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I've been exchanging PMs with Tony123 on his theater build and seeking his advice since our rooms are so similar. I am planning on going with the Atlantic Technology 8200e front speakers (90 db sensitivity) rated at TXH Ultra2 for large rooms (>5,000 cu. ft). This was Tony's PM to me that I thought should be shared on the forum (he gave me his permission to share. He has the Klipsch 650 THX fronts, 96 db):

90db is on the low side. I don't know how to do all the math, but there are guys that can determine for you what db you'd be able to reach at your listening position. And remember, you want the system to be capable of several db beyond your expectations.

I'm not so sure that combination would give you reference volume in a room the size of yours. My first system in this room was the Klipsch Ultra2 at 96db and running off a Denon receiver at 120wpc. It reached reference level, but was straining. I eventually blew a tweeter, and it was just not pleasant at high volume. That's all changed now.

Remember, an Ultra2 system is designed for a space up to 3,000cf. So that tells your right there that you're "undergunned" for your room size. By quite a margin. I learned the hard way and had to change out the system. Buying right the first time is always cheaper.

All my comments are made based on MY expectations. If high volume means nothing to you, then you will likely be fine. But, it's not only volume that you gain, it's dynamics. At the same volume, when there's crashes and explosions, my old system would make people hold there ears. My current system makes them jump out of the chair! The difference is realism, not volume.

I wish you were closer, you could hear and see mine. I think it would speak for itself. Actually, seeing as how our rooms are so similar in dimension, you might find it worthwhile to make a drive. Being in the space can teach you more than months on the internet. You're certainly welcome to if you'd like. Make a weekend of it.

Tony

My response to the above was:
Tony:

Many thanks for your insight! I do wish that I could visit your theater and see for myself. I like things big like you! I have started buying B-stock AT gear because Dennis Erskine rated only 3 companies that made excellent low-priced speakers (Triad, AT & Ariel(?)). Triad is way more expensive than AT.

AT gives the following guidance for their speakers: http://atlantictechnology.com/defaul...alse&NodeId=96

I am collecting their 'large room (>5,000 cu. ft) gear and have already bought the inwall subs and a pair of surrounds. I think that you want to stick the same brand for timbre matching'. I am in a fix. Already committed part way to AT, but also see your point.

Thoughts, anyone?
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post #72 of 148 Old 03-19-2011, 05:47 AM
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DIY,
How is the project coming? Any progress in the last 6 weeks?
- Scott
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post #73 of 148 Old 03-19-2011, 07:04 AM - Thread Starter
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Hi Scott:

Thanks for checking.

Progress is slow because I am finishing the rest of the basement as well (additional 1250+ sq. ft). Since I want to get all the 'dusty' work done before I finish the theater, progress is held hostage to work on other fronts. Currently I am having tile laid in the basement. The next thing will be the shower/bath, doors, trim. Once these are complete, I can focus again on the theater. I am putting up with the delays because the tile installer is a real pro and is laying 24"x24" polished porcelain on the diagonal with inserts for every four tiles for only $2/sq ft labor. He is very busy and comes only when he can. The delay gave me the time to research acoustical treatment methods. I had to call in a 'routine inspection' by the County to get a 6 month extension on my building permit.

In so far as the theater is concerned, I did make a little progress and can report the following:

a) I decided to pull a pair of extra 12 ga. speaker wires to the front stage for passive subwoofers (while I could still access that space before the doors were installed). I got a good deal on Atlantic Technology in-wall IWTS 8e powered subs with a matching 700W RMS amplifier. These are rated at THX Ultra2 performance (105 db in a 3000+ cu. ft. room). I don't intend to make cutouts in my drywall to install these. Instead, I will apply MDF on the outside of the AT-provided enclosures and stand them vertically. They occupy very little space for the performance that they deliver (a foot print of 3-1/2"D x 14"W x 82"H. They will easily fit behind my screen wall and allow me to place the amp in the separate component room. I checked with AT to ensure that this will work and they said that it would. All they care about is 2 cu. ft. volume for the sub enclosure. I used the time to research speakers and am gravitating towards the Atlantic Technology brand.

b) I bought an Emotiva UPA-7 amplifier (125W RMS x 7 for 8 ohms) at their closeout sale. Its no longer available. With 6 ohm speakers it should deliver 150W RMS to each of 7 channels. That should be more than enough I think for my 4,100 cu. ft. room. f not, then I could upgrade to something else for the fronts. I doubt that I will be listening at reference levels. I also purchased a pair of AT 8200 surrounds at a deep discount. It is painful to see all this gear lying around but waiting to be installed a few months down the road!

c) I ordered 1-3/4" solid core doors for the theater from a local millwork company. I needed two with extra long extended jambs for the soundproofing/double stud wall (12-1/4" and 7") that the big box stores don't make. The local millwork company will do this for a nominal fee (I think $10 or so per door). I wasn't sure how I would support the jambs on the theater side since there is a 1-7/8" gap between the double drywall and the studs due to the Whisperclips. I decided to screw 2x4 blocking between the Whisperclips in the door opening to give me something to drive the finish nails through. That should work. The doors arrive next week and BigMouthInDC has been kind enough to volunteer to show me how to install one. I hope to install one door with the long jamb next week. This will let the tile installer place the threshold in the correct location and tile up to it.

d) I have been researching acoustical treatments. I read all the posts by Ethan Winer on the sticky 'acoustical treatments' thread and his website. I think that my treatment plan will be as follows based on Ethan's recommendations: no front treatment, 4" faced Owens Corning 705 fiberglass for corner bass traps, 2" 703 for the first reflection points and the ceiling. I think that I can make sturdy frames using metal corner beading that is meant for drywall and then covering them up with GOM. That should also enable me to offset the fiberglass a few inches from the reflective wall surface. This should be a quick and clean job, I think.

e) My tile installer mentioned that I should consider buying carpet tile remnants from http://www.carpet-usa.com I don't want to install regular carpet because I am wary of flooding. Carpet tile with the plastic/rubber backing holds up better. One can mix and match to create borders and other patterns. I am beginning to look at options from this supplier. Again, prices are much better than a big box store and you have more options.
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post #74 of 148 Old 03-22-2011, 07:35 PM - Thread Starter
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I've been thinking about speaker placement (see attached floor plan). I have never used anything like Audyssey or sound equalization before. I am hoping that these (I intend to buy an Audyssey XT32 preamp) will fix the particular problem that I see coming:

The left and right surrounds are not equidistant from the 'money seat' (Seat #2). The left surround is 6'-5" away whereas the right surround is 9' away. One cause of the problem is the fact that whenever you have an even number of seats in a row, you will not be able to place the 'money' seat at the center and still place the seating row symmetrically around the central axis of the screen. Sliding the seats so that #'3' is the 'money seat' will exacerbate the problem for seat #1.

Would something like Audyssey XT32 address this problem?

I have a related problem (although not quite as acute) with centering the screen - the central axis of the screen runs through seat #2 and is off center for all other seats. I could slide the seats by half a seat to have the screen central axis run between #2 and #3 but that means that nobody will be in the center line of the screen. How big a deal is this? The screen width is about 163" and the screen is about 15' (180") away

 

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post #75 of 148 Old 03-22-2011, 10:06 PM
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My opinion: from a visual point of view, #2 and #6 are both money seats; from an audio point of view, you'll probably just want to run your audio calibration to optimize for those same seats (they will have the delay added to correct for the unequal distance). Every "non-money-seat" in every theater has similar non-optimal audio and video, but once you're watching the movie, you don't really notice unless you're in the most extreme bad seating.

Hopefully someone with a similar setup can give you feedback based on their experience.
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post #76 of 148 Old 03-23-2011, 08:15 AM
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Quote:
Originally Posted by DIYHomeTheater View Post

d) I have been researching acoustical treatments. I read all the posts by Ethan Winer on the sticky 'acoustical treatments' thread and his website. I think that my treatment plan will be as follows based on Ethan's recommendations: no front treatment, 4" faced Owens Corning 705 fiberglass for corner bass traps, 2" 703 for the first reflection points and the ceiling. I think that I can make sturdy frames using metal corner beading that is meant for drywall and then covering them up with GOM. That should also enable me to offset the fiberglass a few inches from the reflective wall surface. This should be a quick and clean job, I think.

Some thoughts on this plan:

1. Why no treatment on the front wall? In an HT setting, treating the front wall is recommended. I suggest you consider treatment of the front wall behind the false wall. I used acoustic cotton, 2" thick and black:
http://www.acousticalsolutions.com/7...FRNl7AodtidZTQ
It's harder to cut than fiberglass, but it's much easier on your skin and respiratory system. It's also "green" as it's made from recycled blue jeans.

2. How is your false wall constructed? Is the whole thing acoustically transparent, or, are the walls around the screen "hard" walls? I would recommend an acoustically transparent wall. Here is a link to the process a friend of mine used:
http://www.peparsplace.com/pg3.html

3. 4" thick panels will not be effective bass traps. They don't absorb to low enough frequencies. If you build the AT false wall as above, the corners behind it become perfect locations for corner traps. My friend has posted his process for that as well: http://www.peparsplace.com/pg23.html
See this link also:
http://forum.studiotips.com/viewtopic.php?t=535
GIK sells pre-made corner traps:
http://www.gikacoustics.com/gik_tri_trap.html

Quote:
Originally Posted by DIYHomeTheater View Post

I've been thinking about speaker placement (see attached floor plan). I have never used anything like Audyssey or sound equalization before. I am hoping that these (I intend to buy an Audyssey XT32 preamp) will fix the particular problem that I see coming:

The left and right surrounds are not equidistant from the 'money seat' (Seat #2). The left surround is 6'-5" away whereas the right surround is 9' away. One cause of the problem is the fact that whenever you have an even number of seats in a row, you will not be able to place the 'money' seat at the center and still place the seating row symmetrically around the central axis of the screen. Sliding the seats so that #'3' is the 'money seat' will exacerbate the problem for seat #1.

Would something like Audyssey XT32 address this problem?

Audyssey will address the problem, as will any receiver or pre/pro that has the ability to set speaker distances, which virtually any new receiver or pre/pro will be able to do. However, it will only be "right" for one seat. This applies to both distance and level settings. You can only have one setting for each, and it will only be correct for one location. Therefore, I would designate one seat as the "money seat" or "sweet spot", and plan everything around that. Audyssey will be able to measure and provide room correction for an "area" around that seat, but the levels and distances will only be correct for that one seat. The Audyssey Setup Guide has a lot more information:
http://www.avsforum.com/avs-vb/showt...5#post14456895

I highly recommend Audyssey XT32. It has done a fabulous job of correcting for the room acoustics of my room. You can see the process I went through here:
http://www.avsforum.com/avs-vb/showt...1#post19446901
That post and several more on the next few pages of that thread describe how I integrated my speakers and subs in my room using Audyssey XT32.

Quote:
Originally Posted by DIYHomeTheater View Post

I have a related problem (although not quite as acute) with centering the screen - the central axis of the screen runs through seat #2 and is off center for all other seats. I could slide the seats by half a seat to have the screen central axis run between #2 and #3 but that means that nobody will be in the center line of the screen. How big a deal is this? The screen width is about 163" and the screen is about 15' (180") away

Again, I would designate one seat as the sweet spot and optimize it. All the rest of the seats will be less than optimal, but that will be the case whether you optimize one seat or not. In the case of the visual image, it's not a big deal at all. It's a bigger deal for the audio, but still, it is what it is. In a "small" room, there is no way around it.

Craig

Lombardi said it:
Perfection is not attainable, but if we chase perfection we can catch excellence."

My System

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post #77 of 148 Old 03-23-2011, 09:17 AM - Thread Starter
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Quote:
Originally Posted by craig john View Post

Some thoughts on this plan:

1. Why no treatment on the front wall? In an HT setting, treating the front wall is recommended. I suggest you consider treatment of the front wall behind the false wall. I used acoustic cotton, 2" thick and black:
http://www.acousticalsolutions.com/7...FRNl7AodtidZTQ
It's harder to cut than fiberglass, but it's much easier on your skin and respiratory system. It's also "green" as it's made from recycled blue jeans.

Craig

Ethan Winer makes this point in several posts on the sticky 'Acoustical Treatments' thread. His rationale is as follows (approximately): "The mid- to high frequencies in the front speakers are very directional and there is virtually no sound 'escaping' from the back of a speaker enclosure in the mid t0 high levels. On the other hand, what does escape is the low frequency. A surface treatment will not absorb those very low frequencies anyway. So, no treatment is necessary for the front wall.
I do agree with your point about the bass trapping in the corners

Quote:
Originally Posted by craig john View Post

How is your false wall constructed? Is the whole thing acoustically transparent, or, are the walls around the screen "hard" walls? I would recommend an acoustically transparent wall.

I am planning on building a false wall using metal studs (minimize warping) and covering with AT screen fabric and GOM. Essentially, it will be an AT false wall

Thank you
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post #78 of 148 Old 03-23-2011, 09:51 AM
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Originally Posted by DIYHomeTheater View Post

Ethan Winer makes this point in several posts on the sticky 'Acoustical Treatments' thread. His rationale is as follows (approximately): "The mid- to high frequencies in the front speakers are very directional and there is virtually no sound 'escaping' from the back of a speaker enclosure in the mid t0 high levels. On the other hand, what does escape is the low frequency. A surface treatment will not absorb those very low frequencies anyway. So, no treatment is necessary for the front wall.
I do agree with your point about the bass trapping in the corners

Read this about SBIR:
http://gikacoustics.com/education_sbir.html

If you can absorb to below the frequency that is causing the SBIR, you can reduce the impact of it. It looks like, from your diagram, that your speakers will be about 3 ft. from both the front and side walls. The wavelength at 3 ft corresponds to a frequency of 375 Hz. You'll have massive comb filtering around this frequency and halves (half wavelength), and quarters, (quarter wavelength), of this frequency. 2" thick absorption on the front and side walls can easily absorb to below 375 Hz, and will reduce the impact significantly.
http://www.acousticalsolutions.com/7...Fcns7QodG1RYjg (Click on Data Sheet)
2" acoustical cotton has a Absorption Coefficient of .94 at 250 Hz and 1.32 at 500 Hz.

Bass traps in the corners will help significantly also.

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Originally Posted by DIYHomeTheater View Post

I am planning on building a false wall using metal studs (minimize warping) and covering with AT screen fabric and GOM. Essentially, it will be an AT false wall

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post #79 of 148 Old 03-23-2011, 10:00 AM - Thread Starter
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I've received some feedback from the Audyssey thread:

a) ensure that the angles are symmetrical
b) consider a 9.2 arrangement using Audyssey DSX for my room

Accordingly, I am toying with the idea of what an 11+ speaker layout using Audyssey recommendations (click here) would look like. See attached speaker layout based on Audyssey guidance. Some immediate problems seem apparent:
  1. The wide front speakers are in front of my AT wall. Yikes! Is that how folks achieve this?
  2. The LRs are too close to the corners. If I move them inwards, the angle will be less than 30 degress recommended for each speaker
  3. The highs are on the ceiling. I will lose soundproofing if I install ceiling speakers
  4. The side surrounds are not equidistant from the money seat, although I have kept the angles as symmetrical as possible
  5. The rear surrounds will cause problems for seats #5 and #8. Too close to them

Given all this, is it feasible/practical to do what I am considering?

Thanks

 

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post #80 of 148 Old 03-23-2011, 11:19 AM - Thread Starter
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Originally Posted by craig john View Post

Some thoughts on this plan:

3. 4" thick panels will not be effective bass traps. They don't absorb to low enough frequencies. If you build the AT false wall as above, the corners behind it become perfect locations for corner traps. My friend has posted his process for that as well: http://www.peparsplace.com/pg23.html
See this link also:
http://forum.studiotips.com/viewtopic.php?t=535
GIK sells pre-made corner traps:
http://www.gikacoustics.com/gik_tri_trap.html

Craig

Thicker bass traps will certainly absorb more, but not proportionately so for the amount of material used. I think that the material used goes up by a factor of two or three but the absorption goes up marginally by 25%. A better use of that material, according to Ethan Winer, is to use more bass traps. In other words, if the choice is between many 4" thick 2'x4' traps with a 'hollow' area behind them versus fewer 'solid core' traps, Ethan Winer suggests the former for more even trapping.

I am trying to figure out how to convert my riser into a bass trap, but have not found a method that can be scientifically defended. Many folks have built these, but I don't know which design is the most efficient.
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post #81 of 148 Old 03-23-2011, 12:13 PM
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DIY,

It sounds like your progress is coming along very well. I'm always impressed by the amount of "homework" you seem to be doing!

I'm no expert in acoustical treatment, but I would suggest that maybe you reconsider the use of absorption on your entire front wall. In addition to other acoustical treatments, I used two inches of absorption on my front wall at the suggestion of one of the acoustical professionals that frequents AVSform. I am extremely pleased with the results.

Your equipment list and progress is impressive. Keep up the good work.

- Scott
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post #82 of 148 Old 03-23-2011, 12:35 PM - Thread Starter
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Originally Posted by ScottJ0007 View Post

DIY,

It sounds like your progress is coming along very well. I'm always impressed by the amount of "homework" you seem to be doing!

I'm no expert in acoustical treatment, but I would suggest that maybe you reconsider the use of absorption on your entire front wall. In addition to other acoustical treatments, I used two inches of absorption on my front wall at the suggestion of one of the acoustical professionals that frequents AVSform. I am extremely pleased with the results.

Your equipment list and progress is impressive. Keep up the good work.

- Scott

Scott, thanks. Two people who have done it and are happy with it have now said the same thing (you and Craig John above). Virtually everyone does the same thing. I think that I will do the same and part ways with Ethan Winer on this recommendation.

I am taking advantage of my 'down time' with the tile work still to be finished. Can't wait to have this thing set up and running!
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post #83 of 148 Old 03-23-2011, 04:31 PM
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Quote:
Originally Posted by DIYHomeTheater View Post

  1. The wide front speakers are in front of my AT wall. Yikes! Is that how folks achieve this?
  2. The LRs are too close to the corners. If I move them inwards, the angle will be less than 30 degress recommended for each speaker
  3. The side surrounds are not equidistant from the money seat, although I have kept the angles as symmetrical as possible
  4. The rear surrounds will cause problems for seats #5 and #8. Too close to them

The setup for the wide front speakers is exactly how it's done.

The recommended angles are not hard and fast. You can do slight deviations. For example, you could move the front speakers a bit inwards and to compensate, you can move the Height and/or Wide speakers a bit backwards.

The side surrounds don't have to be equidistant from the money seat. That will be compensated for in the distance setting in the AVR.

I tend to agree that the rear surrounds are too near seats 5 and 8. If you wish, you can do without them, considering that they have the least contribution. It's your call.

I think the biggest problem will actually be the Height speakers. Ideally, they need to be 45 degrees up, and that's from your ears. If you do the calculation, they'll be on the ceiling. You can either compromise by just locating them as high on the wall as you can or you buy ceiling speakers, ideally with drivers (or at least tweeters) that can be tilted so that they point at the money seat.

Good luck!

Mark
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post #84 of 148 Old 03-23-2011, 04:45 PM
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Quote:
Originally Posted by DIYHomeTheater View Post
I've received some feedback from the Audyssey thread:

a) ensure that the angles are symmetrical
b) consider a 9.2 arrangement using Audyssey DSX for my room

Accordingly, I am toying with the idea of what an 11+ speaker layout using Audyssey recommendations (click here) would look like. See attached speaker layout based on Audyssey guidance. Some immediate problems seem apparent:
[*]The wide front speakers are in front of my AT wall. Yikes! Is that how folks achieve this?
Yep, pretty much. To get 60 degree angles, the speakers need to be out into the room.

Quote:
Originally Posted by DIYHomeTheater View Post
[*]The LRs are too close to the corners. If I move them inwards, the angle will be less than 30 degress recommended for each speaker
I wouldn't get too dogmatic about the front speaker angles. (See the diagram below.) I would place the speakers where they'll have the best imaging and soundstage, not a necessarily at the exactly "correct" angles for DSX.

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Originally Posted by DIYHomeTheater View Post
[*]The side surrounds are not equidistant from the money seat, although I have kept the angles as symmetrical as possible
The unequal distance can be dealt with in the distance setting in the processor. I think the bigger issue is that the side surrounds are well forward of the rear seats. Instead of being "surrounded" in the rear row, the entire soundstage will be in front of the rear row. This is often an issue in HT's with multiple rows. It is often advised to use two sets of side surround speakers, one at 90 degrees to each row. If that isn't possible, then the next best solution is to make the single set 90 degrees to the rear row. They'll be a little too far back for the front row, but that will be better than too far forward for the rear row. (That is unless, of course, the rear row seats are "throw away" seats, and you're more concerned with the sound in the front row, and you're willing to compromise on the rear seats. In that case, keep them where they are.)

Quote:
Originally Posted by DIYHomeTheater View Post
[*]The rear surrounds will cause problems for seats #5 and #8. Too close to them
Yes, this is a real issue. However, it's difficult to address without removing those speakers. One thing you may want to consider is that there are no receivers or pre/pro's that allow 11 speakers in use simultaneously. In other words, if you want heights and wides, you'll need to forgo the rear surrounds anyway.

If you don't remove them, I suggest you re-position them according to this diagram:

Again, as with the front speakers, you don't need to be dogmatic about the angles, but try to get them close.

Craig

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Quote:
Originally Posted by craig john View Post
Yes, this is a real issue. However, it's difficult to address without removing those speakers. One thing you may want to consider is that there are no receivers or pre/pro's that allow 11 speakers in use simultaneously. In other words, if you want heights and wides, you'll need to forgo the rear surrounds anyway.

Craig
Craig, the Denon 4810 (which I used to own) and 4311 (which I presently own) can both do 11 channels simultaneously. However, they have only 9 internal amps so you'd need an external 2-channel power amp if you want 11 channels.

Mark
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Quote:
Originally Posted by streetsmart88

Craig, the Denon 4810 (which I used to own) and 4311 (which I presently own) can both do 11 channels simultaneously. However, they have only 9 internal amps so you'd need an external 2-channel power amp if you want 11 channels.

Mark
Craig, Mark:

The Onkyo 3008 and 5008 have binding posts for 11 speakers. Does that mean that they can drive 11 speakers simultaneously? See pg. 10 of manual at http://filedepot.onkyousa.com/Files/...63b632126165a3

I was thinking of using a 7 channel separate amplifier and 2 or more channels from the Onkyo receiver

However, the back panel of the receiver has a single set of pre-outs labeled 'FRONT HIGH/WIDE'. Does that mean that there are no separate pre-outs for wides and high? How do Folks drive external amps in that situation?

Does DSX necessarily require all 11 channels?

Thanks
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From the 5008 manual, (you meant 5008/3008, right?)
Page 29
http://filedepot.onkyousa.com/Files/...511c39527e5519

Quote:
■9.2 ch playback
􀁠Speaker Layout:SB/FH:
The sounds from surround back and front high
speakers are output by priority.
􀁠Speaker Layout:SB/FW:
The sounds from surround back and front wide
speakers are output by priority.
􀁠Speaker Layout:FH/FW:
The sounds from front high and front wide
speakers are output by priority.
■7.2 ch playback
􀁠Speaker Layout:SB:
The sound from surround back speakers is output
by priority.
􀁠Speaker Layout:FH:
The sound from front high speakers is output
by priority.
􀁠Speaker Layout:FW:
The sound from front wide speakers is output
by priority.
Nothing about 11.2 playback. My Integra DHC-80.2 doesn't allow 11 channel playback either. I wasn't aware that the Denon's could.

Craig

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post #88 of 148 Old 03-23-2011, 08:28 PM
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Quote:
Originally Posted by DIYHomeTheater View Post

Craig, Mark:

The Onkyo 3308 and 5508 have binding posts for 11 speakers. Does that mean that they can drive 11 speakers simultaneously? See pg. 10 of manual at http://filedepot.onkyousa.com/Files/...63b632126165a3

I was thinking of using a 7 channel separate amplifier and 2 or more channels from the Onkyo receiver

However, the back panel of the receiver has a single set of pre-outs labeled 'FRONT HIGH/WIDE'. Does that mean that there are no separate pre-outs for wides and high? How do Folks drive external amps in that situation?

Does DSX necessarily require all 11 channels?

Thanks

Craig beat me to the answer.

DSX doesn't necessarily require all 11 channels. You can have either Wides, Heights or both. In case you can't have both, Audyssey recommends that you use Wides because they have a bigger impact - that is also my experience.

I don't understand why there is a single set of pre-outs labeled 'FRONT HIGH/WIDE.' That does seem to suggest you can't have separate external amps for the Heights and Wides. Unfortunately, I'm not an Onkyo expert so I wouldn't know the definitive answer to this.

Mark
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Quote:
Originally Posted by craig john View Post

From the 5008 manual, (you meant 5008/3008, right?)
Page 29
http://filedepot.onkyousa.com/Files/...511c39527e5519

Nothing about 11.2 playback. My Integra DHC-80.2 doesn't allow 11 channel playback either. I wasn't aware that the Denon's could.

Craig

Thanks. Yes, I meant the 5008/3008. What's confusing me is the table on page 14 that shows an 11 speaker configuration (last column) and the rear panel schematic (page 10) that shows binding posts for 11 speakers
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post #90 of 148 Old 03-23-2011, 09:58 PM
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Quote:
Originally Posted by DIYHomeTheater View Post

Thanks. Yes, I meant the 5008/3008. What's confusing me is the table on page 14 that shows an 11 speaker configuration (last column) and the rear panel schematic (page 10) that shows binding posts for 11 speakers

My understanding is that you can connect 11 speakers but only 9 of them will have an audio signal. Onkyo allows you to select which set of 9 will have a signal.

Mark
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