good info thx Nic

What would I do different?

I will tell you...

I would hide this forum from myself so I stop spending so much $ and time perfecting the untamable for standard hardwood floor family living room environments.

Oh yeah, and after selecting the best possible room in my home, I would focus more on LCR drivers, sensitivity, size, and placement vs trying to understand if the $300 Ultimax 18" Marty Subwoofer is worth spending the extra moolah vs the $99 18" VBSS builds.

The room is sooooo important! The room I picked before I was injected with AVS truth fails the simple clap test miserably.

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Next time i will read more cult infinite baffle forum plus more acoustics books as its is far cheaper than trying to assume know but then finding out my uber project fails bad.

Ie built concrete ib project and avs forum was kicker car subwoofers are a fails
Yup and six blown subwoofers later arrogant me listen to avs forum and i learn that ib is fi car audio ib 318 v2 subwoofers
Dumb me listen so thanks avs forum for telling me about going ib 318 v2 subwoofers

I used UltraTouch ground cotton denim insulation to build 7.5" thick 8ftx8ft and 8ftx12ft sound adsorbers. It took two layers of R-19 batts to get the 7.5" thickness. (Nominal thickness: 2 x 5.5") Some of the batts were undersize in width also and they could not be expanded. The whole process was dusty and I worry about more dust being released by bumping or touching the adsorbers. They are now covered with moving blankets.

The next room went much faster. 8" deep shelves spaced 18" from floor-to-ceiling and wall-to-wall are filled with pillows and hidden by curtians. The pillows are bought in bulk and are nominally 20"x26" The actuall space taken by the pillows on the shelves are 17.25" high and 12" wide. So a 12ft shelf needs 12 pillows per shelf. We did an entire room with shelves-pillows in the time it took to build one Ultratouch adsorber. The cost is about the same per square foot of wall.

Why not just use actual acoustical insulation? 2" OC703 or equivalent plus a 2" air gap to boost performance, and you have some super nice broadband absorption that should outperform the pillows or denim, and take up a lot less thickness? Not criticizing, just asking what brought you to that decision?

http://www.acousticmodelling.com/mli...3=200&v23=3000

The 8" adsorbs more than an octave deeper. That octave makes the differece between "unbalanced dead" and "clean super tight mid-bass."
Male vocals sound natural with the thick adsorbers, not so much with the 2" and air gap.

I can completely cover the room in the time it takes to build one 703 adsober. There's no fiberglass hazard with polyfill pillows.

Doing a full coverage in 703 would cost more than $1000 The pillows and shelves cost less than $500.

I am thinking about 703 for clouds though.

How did you go about modeled polyfilled pillows? There aren't coefficient numbers for them to know where they are absorbing more or less, or did you do tests and measure the absorptive characteristics yourself?

Again, just intrigued by this. Also, I would never tell someone to cover their room in 703 or any absorption technology as that would totally kill the acoustical properties. My room has a combination of absorption materials, including thick denim absorption on the front wall behind my false screen, and my own alternative source of absorption for corner bass traps, so I completely get why you are going different ways. I was still able to model actual results with know materials, so the pillows still throw me a bit, but that's fine. I also would never get away with anything thicker than 4" on my walls (except for the rear wall which is thicker) without feeling the wrath of my wife. LOL

Okay, I'll bite: And the alternative source is ...?

Michael

Shhh.... Don't tell anyone. I would get beat up on the streets for even suggesting this....

Since I had been finishing my entire basement for a year myself, I had a lot of scrap stuff when I got to the home theater (last room to get finished so that I would stay on track with the rest of the basement work). Anyway, I crammed the front corners (and I mean compressed and stuff pretty tight) a bunch of standard, pink, fluffy insulation into the corners. Blasphemy, I know.

I made sort of a "rack" system out of spare plywood where I cut the plywood into triangles as "shelves" and attached them every 2 feet (ish) up the wall in the corner. I compressed and crammed that insulation in there and then these "shelves" made spots for me to staple on black fabric to hold it in. They are puffy, but it is all behind my false wall anyway. Sort of a "super chunk" style, but not using rigid insulation. The triangles are something like 2' on the walls, and (if my math is correct) 2.83' across the front face. My plan was to eventually replace them if they didn't help much, but the bass in the room tightened up very nicely, so they stayed as is.

Again, don't tell anyone. That is why I was asking about someone else's reasoning behind using pillows. It seemed like a similar mind-set that I had when I did these "bass traps" in the corners of my theater back in 2011.

Your secret's safe with me, Nick.

Michael

This thread is very helpful. Thanks guys.

My biggest regret was reading this post here after I spent all this time build a hybrid hush box / return duct system in my theater. All his logic is sound, and I regret not reading it earlier.

https://www.avsforum.com/forum/19-de...l#post55095174

I also made the mistake of sizing my projector box to my current projector and assuming future projectors will be smaller so not giving myself much room.

Nope. They seem to be getting bigger and wider which is contrary to most modern AV tech. I really hope my current projector lasts a long time because I'm kind of stuck with it for now.

Wow, this is about what I spent to soundproof an area of 140 sqm (1507 sqft), including all materials and labour, a sound proofed in-built sliding door, back boxes for all the speakers and sloped star ceiling.

So I would add one thing to this thread so far - have everything designed up front.

I had already signed off the construction of my house before deciding to pull the trigger on a home theater. Numerous plans changed as a result of taking this project seriously and that has meant more cost and in some cases, sub-optimal solutions.

I would also, as everyone always says, allocate significant more space for the theater than I thought I needed to account for all the space wasted for insulation, speakers, decoration etc.

I posted a short list of what I would change if I had known more in my build thread, but I should share it here:

#1 - I went with a fairly large screen, hoping to get a little more height than a 120" and have a wider screen for movies. In theory it is great, and in reality it is great, but it also came at great cost. You can't just throw up a DIY screen or even a woven AT screen when you have a 150" wide screen, unless you have a light canon like a $60k Sony 5000es. You need screen gain to make it work with HDR, even with the excellent tone mapping that is available today with some projectors and processors, and screen gain over 1.0 in an AT screen means you go with perfed vinyl. Micro-perfed Vinyl has drawbacks, even if you sit the required 11 ft + back from it, and worst of all it is very expensive when you get to this size of screen. Simply going smaller on the screen and sitting closer would have saved a LOT of time and money. I could have gone with DIY spandex or a high end woven screen like a V6 Dream Screen and saved thousands of dollars just on the screen.

#2 - Seating. Given that it is hard to sit in specialized seating before purchase, this one was particularly difficult to deal with. In my case, I started with Fusion seating, which is a good value for the money but the ones I went with lacked lower back support and the headrests were just too far forward for a front row. I put them in the back row and went with Palliser seats I had tried out a couple years earlier at a showroom in California when I was traveling. The problem is, Palliser custom makes the seats to your spec, and the level of stuffing changes from seat to seat, so the one in the showroom might be softer, and there is a fairly long break in period before they are more comfortable. Plus the showroom had the high end 3000 leather, and to save a few dollars I went with cheaper 1000 grade leather, which is WAY less flexible. The result was seats that are not nearly as comfortable as they were in the showroom, even after breaking them in and even after removing some fill from the seats. In hindsight I wish I had spent a couple thousand more on the better leather. And really, while home theater seats look cool, sometimes just a good old fashioned couch will work just as well at a fraction of the price. You sit there for 2 hours or more, and you need to be comfortable or you might as well just go to a public theater. Heck, get a few Lazy boy recliners, put narrow end tables between them, and call it good. Much more comfortable and really the big benefit of the home theater seating is having places to put your drink, snacks, and remotes without them falling between the cracks of the couch... Not easy to do when you have 4 across seating and you sit in the middle.

#3 - Design. As mentioned in the post before this, having a complete, detailed design before you ever start building is a major time and money saver. I took the approach of getting a rough idea, build a house around that rough idea, and just wing it from there. I spent hours trying to solve problems and design it on the fly, and I should have done this ahead of time. It's tough for a DIY guy to pay someone to do the design, and for me it only cost me my time when I had to stop and ponder a problem before proceeding, but if I were paying a contractor to do it, it would have been very costly, so there is definitely value in having a pro do the design with details. When building a room that costs $15-20k in materials alone, a few thousand for a design really isn't too far out of a cost.

#4 - Subwoofers. I caught some flak for saying this, but if I were doing it again, I would at least design the bass setup differently if not just scale it down. Part of the reason I went with 6 18's in large vented enclosures was to just try to tame the room by hitting it from all sides. It was successful, but in reality I use about 5% of what I have on "normal" viewing, and maybe 50-70% of the total in the most extreme situations. I had it jacked up higher but it was causing problems like cracked grout upstairs and making the projector move around on the shelf. It's fun, but not really practical. I would have been better off with maybe 4 subs and some MBM's or something... You just don't really need 125db+ at 10hz.

#5 - Soundproofing. If doing it all over, I would either enclose the entire theater in thick concrete walls, or build a single level house so I don't have people above or below it. In both cases, I would go triple drywall with a full room in room construction. The fact is, soundproofing works excellent for frequencies above 100hz, and even fairly well down to about 50 hz. Below that, your DD+GG is like tissue paper, and when you have over 120db of 10hz making everything move, you might as well have just saved the money and not done any soundproofing. If I am going to go through the efforts again, I want it to work well enough to not hear a movie played at a normal volume to be heard outside the room. That would take a lot, I know, but anything less seems like a waste of money. I get all the reasons to do it, including making the room quiet to start, and that is great, but I can do 95% of that with acoustic absorption materials.

#6 - Lighting. You can NEVER have too much, and you should NEVER leave it all on over night. Also, spend the money for better quality stuff. My LED strips in the ceiling degraded and I am now in the process of replacing them, which sucks because I didn't design it to be easily replaced. I prewired for full RGBW, which is good, but this is a lot of work to replace. I will eventually add wall sconces and reconfigure switches to be controlled differently, and thankfully I can hide it all in the ceiling and behind panels on the walls. Dark walls and carpet make for dark rooms in the brightest light. It is great for hiding the dust that collects in the corners and on trim, not great when you need to clean or fix something. And when you have a LOT of lights, they make a LOT of heat. My LED's are powered by supplies in another room, but they still get hot (the reason they are degrading), and the very nicely dimmable incandescent lights give off a lot of heat. I left it all on over night once and the room was over 90 degrees when I went in the next day. Oops.

Mike

So, I've been on hiatus and enjoying my room for 6+ years now, which I guess means I won the "wouldn't have done much differently" lottery.

Until now. I finally decided it was time for a small refresh (low budget in the Theater for Hobbits style, of course) and Atmos has since become the new standard. This of course means running heights, plus some repositioning, and I will soon have a second subwoofer to play around with that came with my new speaker package (the KEF T-series is on sale now for half price).

During the build, there was much advice to future-proof by running extra evergreen cables - power, speaker, RG6, etc - to every conceivable location, and plastic conduit for things like network and HDMI. Which I promptly ignored, because I'm not much of a serial upgrader.

Just do it! It will make life so much easier for your future self.

Now I have to pull out the fish tape, drywall saw, mud knives and paintbrushes back out, and that makes me sad.

The best future proofing? ...procrastination! It's working for me!!!