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Discussion Starter · #1 ·
I'm at the point where most stuff in my theater/basement is finishing up the minor stuff. I gotta say that this has gone a lot further than I originally envisioned, but I'm enjoying the route I took, with the advice of you AVS'ers, more every day... with that said... One of the things that needs the most work is sound treatment. One of my biggest issues, besides echo from nothing on the walls, is bass. I lack bass at my seating position, which is a few feet off center [length of room]. Surprisingly, I get some of my best bass at the actual center of the room, and obviously at the rear. What I'd like to do is clear up some of the bass issues and deaden the echos a bit while trying to use as little of the itchy stuff as I can and without too much trial and error. Am I asking too much, probably...



The room is approximately 25'x11.5'x8.8', not accounting for the tray ceiling and it necking down to about 10' wide near the rear of the room.


I just recently lined all the walls behind my screen in LinAcoustic and boy did it make a pretty significant difference, so much that it makes me want address the rest of the room now.






Aside from the LinAcoustic up front, I have not done anything yet. What I have been looking at is getting some of the ATS acoustic panels and putting on under each sconce (x6). Aside from the front sconces, they'd be the 2'x4'x2" panels; I believe the front would have to be only 1' wide. Below you can get a better look at the spacing of the sconces. I haven't done the mirror test yet, but I think panels under the sconces may place well for the first reflection point.




The doors will get some thick black curtains. There will also be a 3rd sub placed somewhere in the rear of near the back of the chairs soon as well.



In addition to the panels on the walls, I was also looking at possibly getting some 4" panels (with now back) from ATS to hang a couple inches off the ceiling. Will this be beneficial?


Is there any information I might have missed? Can anyone lend some advice? Is there anything else I should be looking at?
 

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If you haven't done so yet, it might be a good time to do some measurements with REW to see where you stand. Are you set on sub location? Did you do the "crawl" to try out alternate locations? How does the bass compare between each of the listening positions?
 

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If you are in a room null it will be a challenge to fix the bass. Drop Ethan Winer a line at Real Traps for lots of advice! http://www.realtraps.com


I would start with some corner bass traps and a few panels along the front side walls and ceiling to kill the early reflections. You might be happy with just that. - Don
 

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Quote:
One of my biggest issues, besides echo from nothing on the walls, is bass. I lack bass at my seating position, which is a few feet off center [length of room].
Any room is going to have reduced bass intensity at its center, and it’s especially bad in rooms with symmetrical (i.e. “shoebox”) dimensions like yours. Play a pink noise signal with a SPL meter handy, and watch the dB reading increase as you move from dead-center towards any boundary. Bass traps are probably your best option for helping with that. Too bad construction is finished; those upper soffits would have been a great place to do some built-in traps.


Regards,

Wayne A. Pflughaupt
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by Brad Horstkotte /forum/post/19629431


If you haven't done so yet, it might be a good time to do some measurements with REW to see where you stand. Are you set on sub location? Did you do the "crawl" to try out alternate locations? How does the bass compare between each of the listening positions?

I was looking at REW last night after I read this (briefly looked at it over the last year)... If I want to just take measurements, it looks like I just need and SPL meter and the sound card? Am I missing something? I won't try to correct with a manual equalizer as I have an 8033, which does good for my tastes, just can't solve this problem.

Quote:
Originally Posted by DonH50 /forum/post/19629690


If you are in a room null it will be a challenge to fix the bass. Drop Ethan Winer a line at Real Traps for lots of advice! http://www.realtraps.com


I would start with some corner bass traps and a few panels along the front side walls and ceiling to kill the early reflections. You might be happy with just that. - Don

I may do that. I was looking at the site yesterday and was looking at his Bare Traps. I know I can save some money making them myself, but I have no desire to mess with fiberglass anymore. I wish I had put the LinAcoustic up before the carpet went in. I have to get some tape to seal up the ends, but I can tell there is still a little fiberglass floating around in the room.

Quote:
Originally Posted by Dennis Erskine /forum/post/19629984


The automatic knee jerk reaction is to kill the early reflections as a first step. In many cases that is the wrong first step. BTW, can you see the pretty copper drivers through your screen when playing a movie?

Are you talking about the first reflections from the mains?


No, even when I don't have the grill on, you cant see the drivers.

Quote:
Originally Posted by Wayne A. Pflughaupt /forum/post/19631338

Any room is going to have reduced bass intensity at its center, and it's especially bad in rooms with symmetrical (i.e. shoebox) dimensions like yours. Play a pink noise signal with a SPL meter handy, and watch the dB reading increase as you move from dead-center towards any boundary. Bass traps are probably your best option for helping with that. Too bad construction is finished; those upper soffits would have been a great place to do some built-in traps.


Regards,

Wayne A. Pflughaupt

That's the thing.... The actual center of the room sounds great; I sit just behind it by about 3 or 4 feet. I also have a ton of bass in the space between the wall and chairs.
 

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I think at this point it will be a process of trial and error. I agree with Dennis Erskine and SierraMikeBravo that early reflections likely shouldn't be first on your list. Two things I'd look at is placing one of your subs in one of the back corners of the room, probably to the right behind the cabinet to address some bass issues. Secondly I'd look at the room decay times and target something in the order of the high three's, a little absorption will go a long way and will likely require a mixture of facing-out/facing-in panels to achieve a decent balance (depending what you cover the rear glass with you might not be that far off). I'd start with a couple at your soffits and measure those results, make sure you do some measure with a couple bodies seated in the room as well as this will have an equal effect as well in that room. Target a decay that's relatively flat from top to bottom.
 

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Discussion Starter · #9 ·
I'll try out a sub in the rear, but I really want to keep the subs hidden. I will have a 3rd sub to hide in the rear soon, but I am hoping I can improve the room before that.


The weather is very bad here today, so I'll see about heading to Radio Shack tomorrow and download REW. I'd like some graphs to show what I'm dealing with. I will also place an order for some ATS panels this week.


Any thoughts on my idea for the ceiling?
 

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Quote:
Originally Posted by yamahaSHO /forum/post/19632949


I'll try out a sub in the rear, but I really want to keep the subs hidden.

Hide the bookcase/don't hide the bookcase, hide the chairs/don't, hide the rear speakers/don't, hide the pj/don't, hide the doors/don't. What does it matter if the subs are hidden? Just put a couple Bose "cute cube" posters on the wall and all SQ expectation factors will be neutered.



If buying acoustic panels blindly, I'd start with two 2x4 panels and perhaps 4 and try to get the absorptive material "faced" so the panel can be reversed to reflect relatively varying amounts of high vs lower frequencies as this will allow greater tuning flexibility. If it were me I'd pick up a case of 2" faced acoustical insulation for $50 and experiment with that prior to investing in a commercial finished product. If you spend hundreds of dollars on a product it will likely be hanging on your walls regardless of the end result....$50 on some stuff that smells like cat piss will ensure you'll use it only with good reason.
 

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Discussion Starter · #11 ·
I wouldn't say I'm buying acoustic panels blindly, but at this point, I'd much rather pull it out of a box and hang it up, vs building a frame and messing with insulation (which I hate) myself.


I did plan on quite a few 2'x4' panels on the walls.... Probably 4 of them on the walls as well as two 1'x4' panels due to the light being so close to the screen. The problem I see is that I know that this will do nothing with the bass, which is my biggest concern at this point.
 

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Discussion Starter · #15 ·
Thanks for the link, it is very informative. As much as I'd like to give the service a try, I'm honestly not willing to spend $600 on it. I'm sure they do a great job and the service is worth that, but the wife wouldn't see the point in it. That means something since I have to talk her into spending money on all my other pricey hobbies.
 

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Here is one suggestion. Take a sub, get the driver/port near to the ear level in the listening position. Then move the mic around and measure any spot you could imagine using a sub. In my case, I try crazy spots like in the ceiling, floor and midway in the air - I can get creative if they turn out to be nifty. You get some good data that way. Then repeat for the other seats.


That gives you a hint with what you will achieve. Now when combinine multi subs, where phase is not altered, they will combine such that the peaks will add, but the peaks will not subtract. In other words peak + dip = peak. They don't average out, but the maximum SPL will dominate. So you place your multiple subs to eliminate the dips. When you look through all your plots you have good information to get you started with what sub positions to try together. So you measure for half an hour instead of moving subs around for 10 hours.


Dennis,


You don't agree with the convention of absorption for first reflection points? Curious to hear your thoughts if you don't mind expanding.
 

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Discussion Starter · #19 ·
Okay... I've made a first step towards getting a better sounding room. I obviously haven't addressed the bass issue yet, but I'll get there.


I got 6 ATS acoustic panels in today. I got most of them hung and I do like them. They are very well made, look good and are pretty easy to hang. I will have to order a few more and the ceiling will have to be addressed.


Right now I'm trying to decide how to mount this panel sitting on the ground. I am looking to center it between the other two, but instead of making it the same height, I think it would look better offset. Right now we're thinking of mounting it a little lower than the other two. This is ideal for sound as well, right? I know many will mount panels and such down low up front.





 

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Jason, that drop ceiling around the corners is a great spot for bass trapping. Did you have it made for bass absorption?
 
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