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Discussion Starter · #1 ·
I have a new house that had a pretty large exercise room in it which we are in the process of converting to a home theater room. I really wanted the largest screen possible and ended up getting a Seymour XD screen from Jamestown screens which is awesome. The problem is now that the screen takes up the entire front wall almost I have nowhere to place subs. I have some paradigm on wall signature W5's for my LCR which are pretty good for their size that are going behind the screen after cutting out a little drywall. I just don't have the room to put giant subs there and due to configuration of the room there really aren't too many places I can place them at all. I read the Harmon White papers which are awesome and it looks like 1/4 spacing from walls is an ideal setup, I'm just wondering if it is ok for me to do this on the left and right walls instead of front and back? The room is 21'x20'x10'. Possible sub placement in red.






Here are the possible subs. Thanks to LTD Gorilla83 and Carp who this was originally designed for.

 

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Quote:
Originally Posted by uopdrmark  /t/1524582/new-low-profile-marty-placement-help#post_24538020


If anyone is interested in the original thread for the new design you can find it here: http://www.avsforum.com/t/1523780/flatpacks-for-a-tall-small-footprint-18-ported-sub

Holly Toledo! 170 " wide or diagonal screen? If wide, you are definitely looking at 3chip DLP!


I don't think my 1000 would light that up and it's a fairly bright projector. Why 1.78? That room screams scope.....
 

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Discussion Starter · #4 ·
Sorry... it is 170'' diagonal. I have an Epson 5020 and it seems great to me. Maybe I have low expectations but I lived with it for about 6 months just projecting on the wall before buying a screen. Jamestown is awesome as a AIY product for about $710 shipped. Too be honest I think I should have gone 160'' diagonal as I didn't really take the frame into account on the wall itself which really makes a pretty big difference. You can see your S2 on the wall in there now doublewing. It definitely can hit hard but the room needs some serious acoustic treatments and I think 4 subs will even things out much better than the single S2. I only ended up with about a foot off the ground once we mounted the screen and I would have gone lower but it got in the way of my feet being on the ottoman which can't be done! So now I'm trying to figure out if placing subs along the side walls will work well or end up with localization or other problems.

 

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Those windows and doors are going to create huge suck outs........ie. unwanted bass traps.


I see your issues........


I tried to rotate room and still same issues.


Have you thought of making some window plugs?


Yeah, multiples definitely needed.......


Two on sides look to be promising.........maybe S2 behind couch and move for best FR . Those two on side could be placed at mid-line. You're definitely needing to learn REW software and move subs around to find sweet spot.
 

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No room in that front right corner?


The best is to measure and move the sub around. Find the best spot and put it there. But if you don't have that capability and aren't inclined to get it, then two things. First, you're compromising. Ok now that's out of the way, then put it where possible. The sides are fine. I wouldn't worry about the windows either. Put it where you can and make it work. If it doesn't sound good, try a new spot.


Good luck
 

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Look on bright side, your drawings show only one row of seating which is good! The only area for bass that matters are your seating positions.


As mentioned above, learn REW and move subs around until your happy. Nulls in non-seating areas are NO big deal. Once again, I 'd start first with mid-lines at side wall and move for best overall FR.


On another note, window plugs WILL help with FR.........think of your room as an aquarium.......sound is sure going to leak from those windows!
 

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Quote:
Originally Posted by doublewing11  /t/1524582/new-low-profile-marty-placement-help#post_24538417


On another note, window plugs WILL help with FR.........think of your room as an aquarium.......sound is sure going to leak from those windows!

Hi doublewing11,


Can I ask if you've done any testing regarding this statement? I know bossobass has, and so has BillF and they would disagree. Here's a quote from BillF in one of my threads regarding windows.
Quote:
Originally Posted by Bill Fitzmaurice  /t/1446510/help-with-room-treatment-with-diy-mentality#post_22735527


I did some measurements today to compare the low frequency reflectivity of glass versus walls, with surprising results. I grabbed my handheld RTA and switched my HT source to pink noise, then measured SPL a few inches from the walls and also the windows, one of which measures 5x5 feet. From 20 to 80Hz there was no discernible difference.

I took a 40Hz reading at the 2 inch solid oak front door, then opened it, revealing the glass storm door. The level didn't change. Then I opened the glass storm door, and the level dropped by 6dB. I went onto the porch and took a reading with the storm door open, then closed it. The level went down by 6dB. I then closed the inner solid oak door, the level went down another 6dB. So inside the room the reflectivity difference between walls and glass was negligible, that between glass and air significant. To tell the truth I'd expected the reflectivity of the glass would be at least a couple of dB less than the wall, but it wasn't. Glass does allow a lot more transmission of low frequencies than walls and doors, but that transmission doesn't mean that no energy is reflected back into the room. On the contrary, in this test glass and walls were the same.

This indicates that windows not only don't act as bass traps, they probably need damping just as much as walls do. But since windows tend to be a small percentage of the total wall area, and seldom are in the room corners, I wouldn't be all that concerned about them. The main issue they'll present is environmental leakage.
 

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Discussion Starter · #10 ·
Wow... thanks for the responses.


doublewing: I am planning on learning REW with many thanks to all of you here, especially Chalugadp's new tutorial. (What mic do people recommend for this? And how does Omnimic compare?) Do you think I should just start with 2 subs at L/R midline and go see how it sounds and add from there? I guess I am trying to figure out placement as best I can before starting so I know what form factor to make and how many to get. I was planning sealed as we discussed but the output on the sub listed above just destroys the sealed versions down to 8.5hz where the sealed takes over. Even 2 big ported subs go down to 11.5 before the sealed takes over with the sealed having more headroom overall but the ported still do about 124+dbs from 16-100hz.


Tux: I am totally willing to move the subs around and the right corner on the screen wall does work but sounds aweful at the listing position. The front center was way better but the new screen is now in the way. This is part of why I want to go to 4 subs to help with response. I could just build sealed or martycubes and push them around but I really don't want them to stick that far off the wall if possible.


Mrkazador: I am talking with Urapnes1 and he just mentioned this idea as well. Behind the screen is outside the house and could be pushed out, I'm just assuming that would be very expensive. There is crawl space in the ceiling that could be used, I just have no clue as to how to accomplish this and again you can't move it once it's in so I'd still have to deal with room issues. And probably the biggest issue is that I am totally inept when it comes to this stuff and I'm hoping I can get Urapnes1 to help on the builds and cutting holes in my house just sounds scary
 

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Quote:
Originally Posted by tuxedocivic  /t/1524582/new-low-profile-marty-placement-help#post_24538485


Hi doublewing11,


Can I ask if you've done any testing regarding this statement? I know bossobass has, and so has BillF and they would disagree. Here's a quote from BillF in one of my threads regarding windows.

Erskine Group would disagree and have mentioned such issues over time. Now I'm not an acoustical engineer.......but thin glass and Sheetrock have vastly different properties.......Including acoustical properties. Think about it.......why in the world would I go to great lengths to seal a room, yet have a window in the middle of room and not expect repercussion?
 

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Discussion Starter · #13 ·
I have no problem with the conversation. It sounds like it may make some difference for me so no worries about being off topic.


So given the space I have to deal with would it be better to do 2 subs along the right and left midline's? The Harmon White paper seems to show 2 subs are pretty close to 4 subs as far as room response. As long as the subs are powerful do you think I might be able to get away with just 2 or should I stick with trying to get 4 in there? I already bought 2 inuke6000dsp's so I'm ready to do 4 but if there isn't much benefit I won't force it. I'm also open to doing more custom designs to try and fit things in the room better as well if others have some ideas.
 

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Well, it depends on your SPL and bandwidth requirements. You say you have a Marty sub already. I'm not to familiar with that. Some kind of LLT I assume. So you should get quite a bit of output from 2. And you could probably strong arm the response into shape with eq. However 4 would make this easier.


Is space a concern? If it is, consider staking them or going sealed.
 
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