Need help with Acoustic Treatments!

[AbMagFab]

I've read the primers, and I understand the need for them, and I really want to do them. My dedicated HT is finally at a stable point, since I got my new speakers.

I know that the long way to get this done is a deep analysis of my room. However, since I have a relatively simple room, and it's basically a box, I figure the end result would be pretty much what any experienced person would figure out anyway?

From what I've gathered, I need to put panels at the first reflection points on the side walls and ceiling. In addition, perhaps something on the back wall (since it's so close to the seating), and maybe the front wall behind the front speakers (and behind the screen?). And then bass traps, although I'm concerned about the appearance of them.

I'm willing to spend some money on this, but would like to keep it reasonable if possible. I can definitely DIY (I've built my basement myself), but if it's not much more expensive to buy the panels pre-made, I'm fine with that.

I don't have the post count yet to post links, but you can see my room over at avs at:

avsforum.com/avs-vb/showthread.php?t=1015097

Thanks in advance for any advise!
-Mark

 

[Glenn Kuras]

Honestly it sounds like you have a pretty good grip on this. I would just recommend dealing with a company that will provide a little more detail about which product vs placement, is best and you should be good to go.

Cheers on doing your home work before hand.

Glenn

 

[Jack Hammer]

There are quite a few companies with reasonable prices for pre-made panels. That said, I bought mine from GIK Acoustics and have been very happy with both the quality and the function. The people there were extremely helpful in recomending what I needed to get started, without selling me stuff I didn't need. They had me send pictures of my room and asked what I was looking to accomplish before they directed to a specific product.

Whether you decide to purcase pre-made or make your own, you should still post some pics of your room to see if others can help you decide where you need treatments and how much and what type of treatments you may need.

Jack

 

[ParadigmDawg]

I second the rec for GIK. I have their Elite panels and they are very nice.

 

[bpape]

Mark.

You have the basics down. The trick is identifying how many and specifically where to place them. It's also a matter of getting the most benefit for the budget and staying within the aesthetic consderations.

As an example, if we're close to budget, unless you have a low ceiling or center channel mounted up high, the ceiling panels could be put off until later without adversely effecting the overall room treatment scheme.

How many rows of how many seats do you have and what are the room dimensions?

Bryan

 

[Warpdrv]

Here is a link to his very nice new setup with pictures... http://www.avsforum.com/avs-vb/showthread.php?p=13540963#post13540963

Doesn't look like a huge room, but it is nicely put together.... Looks Beautiful.

Great Job AbMagFab.... List your room dimensions for Bryan, and he can help you further... GIK is a great company to deal with.

 

[AbMagFab]

Thanks! My overall room dimensions are about 11' W x 15' D, projection screen, front speakers on a stage (filled with sand - thanks to the threads here on how to properly build a stage), one row of three seats about 11' from the screen.

I've done the mirror-method first reflection points for the front channels. Based on that, I need three panels on each side wall, although thanks to a wall switch on one side, and the location of a chair on the other side, two of those three panels will need to be custom sized, and I'd like both walls to match visually. So 2x4, 3.5x4, and 2x2.

For the screen wall, do I generally want to cover as much of that wall as possible? At least the bottom 4 feet of it? So that's 4 more custom panels (two on the bottom, one on each side).

What about behind the screen? I could at least put some 1" 703/705 behind there, if it makes a big difference (although I dread taking that screen down, for fear of screwing up the screen material in some freak slip of my hands/feet).

For the back wall, the door handles make 2x4x4" bass trap panels tough, so I'd need custom panels there as well (like 3'8"x2'x4").

For the rear corners, I can put 2x4x4" panels in the bottom, but I'd need custom ones for the rest of the wall (although my rear speakers might make that pointless, as I couldn't get a full 2' diagonal based on their location).

I'd really like to just buy from someone and get this done. But given the number of custom panels, it seems like this would be substantially cheaper to do it myself? I have budget, but I think we're approaching a 2x or 3x factor versus doing it myself, and I could use OC705 (it seems like most pre-built ones use a substitute, which I guess is okay, but why not use 705?). I can also custom make the rear corners to almost look like part of the room (put some baseboard on the bottom, maybe even a little shelf on top if I only do 4-feet high, cut the sides on an angle to butt up seamlessly with the walls, etc.).

Sorry for the rambling... I'm diving in head first, and circling in on exactly what my next step is. And I like to move fast, so I'd like to order something from somewhere (either pre-made, or the materials) by today or tomorrow.

What are all your thoughts on this?

 

[AbMagFab]

Well, just pulled the trigger and ordered a bunch of stuff to do acoustic panels for my room. Decided to DIY for the following reasons:

1) Use better material - OC705 instead of mineral wool
2) A lot of custom panels - I think I'll have 12-15 panels (2" and 4" thick), and only 3-6 of them will be 2'x4'
3) I'm handy enough to do this easily
4) With all the custom work, even with the better material, it's 1/2 to 1/3 the cost of having someone else do them
5) I can do some custom shapes as well, like slight trapazoids

So I've got 24 OC705 2'x4' sheets coming, plus 20 yards of black fabric (I wanted black, it's a dedicated HT so the more black the better), and some accessories.

Only thing to nail down now is the framing. I think I'll use 1/8" ply/luan and just do outside frames (to keep the edges square and solid). I think I'll bevel the front edge 45-degrees for a subtle finished look. That should keep them light enough to hang with the fiberglass hangers, but worst case I'll put a brace along the back and hang from that. I'll attach the fabric mostly with the 3M spray glue, since that seems to be a favorite of most people, and with the 1/8" frame I should be able to pull it pretty tight. Worst case I'll put a small frame around the back, adding about 1/4" of depth, and staple to that.

Anyway, as I get moving, I'll post pictures if anyone cares.

 

[bpape]

If you're going to DIY, save your money and get 703 for half the price. With what you'll be doing with it, it will perform just as well as 705. Mineral wool is cheaper yet and can work in the same way - though it can be a PITA to work with sometimes.

Bryan

 

[jostenmeat]

I just sent a healthy chunk of money to a dude for 10 used treatments. 8 are full sized bass traps, but all are of the HF variety. I'm glad that I'm finally getting around to this. My stereo room is more or less the size of your room, at least after I removed the closet mirror-doors.

A modest room such as ours needs a lot of work on the bass first of all. (Mine included, but I have horrendous slap echo, hence the HF versions).

I'd do the corners first. Even if parallel to a wall, you'll want a minimum of at least a few inches for maximum effect. This way, if I understand correctly (my knowledge is often questionable, hehe), the bass wave gets "treated" or attenuated 3x before coming back to you. Once thru the trap, the wall absorbs a wee bit, then a final time coming back thru the trap. At least the traps that I am buying.

So, at the least you could do the 4 vertical corners, if you don't possibly mind moving speakers and sub just a wee bit. You might also plan like me, and do the sidewalls/ceiling boundaries (but my intent is also to tame slap echo). The front wall is where the most benefit will come from with trapping. I am planning on at least 4 full bass traps for the front wall. I see the pic in the thread Warp provided, and you might pull off corner tritraps in addition to the vertically placed 2x4 traps.

Treating reflections is a great idea. In stereo setup, there appears to be varying tastes, ie dead-front + live rear, or just dead-period, etc. But in HT, it appears to me that very dead is the desired effect. I was hoping to use extra treatments in my HT, but I don't think I'll have any left. In fact I might buy more HF panels... I think I'll need one for the rear wall. I am afraid that the reflection there at such a short distance from ears (def under 6 ft) will appear more like smearing than ambience.

This is all "theory" I suppose, and nothing like physical experimentation. Most of what I know comes from a couple of very helpful folks I found at AVS.

Finally, GREAT ROOM! mind if I ask what kind of pj and screen?

Cheers, j

 

[jostenmeat]

I forgot to address something. OK, it appears your room is 15' length, and you sit 11' from front wall? If you get your ears to 9.3 ft from the front wall, you will have acheived a 38% room-length distance from the rear wall. This % is the recommended for best positioning of the ears to avoid unwanted peaks/nulls AFAIK. (I have a piece of masking tape of the carpet to mark mine off).

Now, Im not saying its absolutely imperative. After all, the display rules all in the world of HT. But, if it's not too close, its definitely worth a try.

 

[AbMagFab]

It's a Sony VW60, and a Stewart 110" (diag) 16x9 FireHawk G3. I love them.

So here's what I've decided I think:

- 2x4 4" bass traps in the rear two corners, going half way up the wall (more than half actually, because of the soffet)

- 2x4 4" bass traps on the rear doors

- 3 2" panels on each side wall

- 2" (or 4") panels on the screen wall, around the bottom 4-feet of the screen. Perhaps since I can't do bass traps there (one corner has the door, the other corner has the speaker), I'll do 4" panels?

- Maybe 3 2" panels on the ceiling, depending on what it sounds like after the rest is done

For the rear corner traps, I'm going to mitre them so they fit snugly in the corner. I might even run baseboard around the bottom and put a little shelf on top to make it look more like part of the room. Or I might go up the remaining 3.5' with a half-sized on (like 1.5" wide), since I really can't move the speakers there.

For the side wall panels, I'm planning to make slight trapezoids, just to make them look a little nicer than rectangles/squares. Plus, 4 of the 6 need to be custom sized anyway (only one can be 2x4).

The screen wall is all custom, but I figure two 4-foot wide panels below the screen, and 2 4-foot high panels next to the screen from the stage up. Maybe I'll just deaden the rest of the front wall to the ceiling?

So, some quesions I guess:

1) Is it worth deadening the screen wall all the way to the ceiling, or just the bottom 4-feet?

2) For corner bass traps, do I get any benefit from a 1-foot wide panel (at 45 degrees), or is anything less than 2' wide simply not worth it?

3) What do people generally think of ceiling panels? I keep getting mixed responses, so not sure what the rule of thumb is on this. I have no problem doing them, but if it hurts more than helps (or does no good), I'd rather focus more on the other areas.

Thanks!
-Mark

 

[AbMagFab]

I forgot to address something. OK, it appears your room is 15' length, and you sit 11' from front wall? If you get your ears to 9.3 ft from the front wall, you will have acheived a 38% room-length distance from the rear wall. This % is the recommended for best positioning of the ears to avoid unwanted peaks/nulls AFAIK. (I have a piece of masking tape of the carpet to mark mine off).

Now, Im not saying its absolutely imperative. After all, the display rules all in the world of HT. But, if it's not too close, its definitely worth a try.

Hmm... I'll have to see where that is. I think the biggest problem with that is when reclining, it adds like 1-2 feet to the viewing distance, so it would be hard to be 9.3-feet when reclined I think?

But good advice - I'll measure it out and see where it is. Thanks!

 

[jostenmeat]

I didn't quite understand the entire plan of attack, but it seems you are well on your way with great ideas. And if the pics of the room are any predictor, I'm sure whatever you do will look fantastic. Great equipment btw, you don't mess around.

So, some quesions I guess:

1) Is it worth deadening the screen wall all the way to the ceiling, or just the bottom 4-feet?

2) For corner bass traps, do I get any benefit from a 1-foot wide panel (at 45 degrees), or is anything less than 2' wide simply not worth it?

3) What do people generally think of ceiling panels? I keep getting mixed responses, so not sure what the rule of thumb is on this. I have no problem doing them, but if it hurts more than helps (or does no good), I'd rather focus more on the other areas.

Thanks!
-Mark

1) The persons that I admire/appreciate the most seem to cover the entire front wall in treatments. So, if I pick my idols well, hehe, the more the better. Ok, maybe not "entire" but at least lined up all the way from left to right I think.

2) Anything is better than nothing. The smaller the room, the greater the requirement of bass trapping. Experiment I suppose. Remember, this is all "theory", right? With such a capable sub like yours, Id trap the hell outta the place to get the most accurate effects w/ least amount of boominess/muddines.

3) To me that's interesting that some people say that it actually hurts. I haven't seen that said yet, and I do wonder why that is. They are still reflection points, right? Personally, I am a little worried that I am not going to have ceiling treatments on my first big go here. I miiight have one HF bass trap at the front wall/ceiling boundary, slightly covering the lone window. I don't think so, because there are too many vertical boundaries to take care, and I still need to address slap echo.

Anyways, remember that to get the maximum effect from your traps, you want a bit of space between them and the wall/boundary. Could you have panel(s) running below screen at a 45 deg angle maybe? And please definitely remember you are receiving advice from a noobie.