Acoustic treaments for my combination room

Hi Gang, My construction thread is here. It's been a long haul, but I'm getting close to completion, and thought I'd see if I could get a little input regarding acoustic treatment. I've currently got 20 pieces of 2' X 4' X 4" rockwool, 4 lb density that I'm planning to build bass traps out of. I laid out my room in the attached sketchup, and placed treatment as best I know how. This is a combination room, and I've used text to mark where I plan to have the mix position. If you aren't familiar with my project, part of the goal was to build this room so it could be sold as a bedroom when we sell the house someday (my wife's pre-requisite for allowing me to begin construction). This is why there is a "closet", which I plan to eventually install bi-fold doors on. If I am advised to leave those doors off for now for better acoustics, I will consider doing that. The sketchup should be pretty close to scale. I realize a few of the bass traps are still penetrating walls, but since I am a sketchup rookie, I hope that you will forgive my inexperience, and please advise if there is something that I need to do differently to make it easy for you to view. The brown panels represent 4" rockwool panels, mostly 2' X 4' (but a couple are 2' X 2'). Most of these should be positioned roughly 4" from the wall and many are across corners. The grey panels represent 2" rockwool and are positioned directly against the wall, ceiling, or doors where I didn't have room for thicker panels. The brown panels right in front of the closet are to be portable gobos mounted on some type of stands. I'm open to advice. I'm assuming that since the room is so small, I will need to deaden it quite a bit, but please tell me if this would be going overboard. I should mention the floor is laminate, and I will likely have a rug at least under the drums (which are electronic). I'm close to getting the floor in the room done, then I need to do trim (mop boards, finish window, etc). After that I plan to use REW to test the room and monitor as I add treatments, but just wanted to get some input on what I thinking for treatments at this point. Thanks in advance for any advice you can give me. :D

I decided to post some images, so you can see some of the contents of the sketchup file in my last post without having to download and navigate through it. I'm not sure how helpful these will be, but here they are anyway. As I explained in the previous post, the brown panels represent 4" rockrool (mostly 2' X 4', but with a couple 2' X 2') mostly positioned 4" from the wall/ceiling or across corners. The grey panels represent 2" rockwool mounted flat against the surface where there is no room for 4" panels. Again, I welcome any comments or advice. Thank you!

Ok, let's try a more specific question. With the 20 pieces of 4" rockwool that I have at this time, I have also considered using roughly half of it to build super-chunk bass traps on the two near corners in the image below rather than just putting 2' X 6' X 4" panels across the corners as shown, and cover less of the rest of the room surfaces initially - of course I'd buy more rockwool and build more traps if still needed. Would this be a better initial approach? I haven't yet got to the point of testing the room with REW, but my understanding is that will mainly be more of a way to mark my starting point so I can gauge the effectiveness of my treatments, right?

Hi, what does it sound like now? Do you have a freq spectrum analizer that you could post the results? It seems like alot of high frequences will be absorbed, which will result in a dead room. You will find your mixes won't translate well in other rooms. Slat resonators will prob be the way to go.

Hi LE! Thanks for your response. Just to be clear, I’ve not done any treatment as of yet – what is shown here is only my first idea on how to proceed. (My construction post is here). I was planning to try to get the trim in the room done, then attempt to set up REW to do some analysis and post the results (I will be a complete rookie at this). Currently (without treatment) the room is pretty live as you might imagine, and by singing a few notes, not surprisingly, you can quickly identify at least one resonant frequency. I finally took my acoustic guitar down and played it in the room a little the other day, and the room ambiance seemed to compliment that nicely, but it’s way too live to be functional as a combination room at this point. Perhaps I should not wait and start trying to fire up REW right away to post some useful information so you experts have something to work with. I was concerned about the room being too dead also, but am getting the impression that with a small room like this, it might be the only option. I was encouraged by doublehelix being happy with the sound in his control room after so heavily treating it. His project is here. I should also mention that I am planning to wrap the rockwool in plastic before covering with burlap, which I assume would help a little in regard to not absorbing high frequencies. I have done some reading about slat resonators but have yet to develop even a foundation of understanding about them at this point. Thanks for your comments, and I welcome any further input. By the way, looks like you have a very nice space and lots of killer gear!

My mate has hung 3 panel absorbers per wall with corner traps and his room sounds like mud. But the plastic covers sound like a good start.

I can certainly see why you would think mine would be very muddy then with all the panels I'm proposing. Do you know how thick those panels are and how far are they mounted from the wall (and what they're made of)? I started playing with REW tonight a bit, so perhaps it won't be too long before I can provide some graphs of what's going on in the room before treatment. Thanks again for you input lilith_envy!

Hi All, Below is one of my first waterfall graphs from REW in my room. I would welcome any advice on different settings I should use, or other information I should try to gather before beginning to install treatment in my room, or advice on changing my current plan in regard to treatment. I would assume some type of RT60 might be useful? Anything else? Please forgive me for my lack of knowledge in this area at this point. I would REALLY appreciate any advice, insight or obvservations. Thank you!

Hi All, I am finally getting around to documenting what I did for treatment in my room. As I mentioned above, I purchased 20 pieces of 4” thick 2’ X 4’ mineral wool to build bass traps out of. I basically used the design described by studio_drums HERE which I highly recommend. The most significant change I made to this design was to put the mineral wool into garbage bags (2 garbage bags per 2’ X 4’ sheet of mineral wool) before assembling, for two reasons: 1) To make sure mineral wool particles would stay put and 2) reduce high frequency absorption. Before I started treatment, I used REW to take some initial readings, some of which I will share in the next post. Next I built bass traps out of the mineral wool, put them in place and did more testing. From my limited knowledge in looking at the post treatment REW tests, and by listening to the room, I believe this is enough treatment. I was quite surprised to see how much the graphs improved. Anyway, first I will provide diagrams similar to the treatment plans I provided above (in previous posts) to show you how I actually treated the room, which is somewhat less than I had planned. In other words, I had assumed I would need to buy more mineral wool, but to me it appears I already have about the correct amount of trapping.

Following are the graphs from REW from before and after treatment. I tried to keep the test conditions as consistent as possible, and did 10 runs for each test and averaged them. If I had to complain about the (post-treatment) sound in the room, it would probably be that it's too dead, but to me, it's not unnaturally dead, and for a combination room, I'd rather have it too dead than too live. Regardless, I'm very happy with the room, and am so glad that it's finally done and usable! :yahoo: It's actually been completed since just after the 1st of the year. If you're interested in pics of the finished space, they should be on my construction site HERE very soon.

I have finished my construction (here). I'll make one last plea to please comment on my treatment and measurements above to give others who run across this thread an idea of whether this acoustic treatment should be considered a success or not (though I realize it's all relative). From the little bit of mixing I've done so far, the bump around 60 hz, may be problematic, but I need to spend more time with the room to discover how much of a problem it will be. Thanks so much!

It very well succeeded imho. I'm sure Ethan can give you the full speech. I have little experience "measuring" rooms with software. Should catch up I reck'n. I use my ears all the times. Heck, I should first measure my ears then, shouldn't I ! haha I think, however, you could use a bit more low-end trapping.

Hey Ro, I'll bet your ears are just the right distance apart from each other - no need to measure! :D I would love for Ethan (or any of the other acoustic experts here) to comment on this. It was from reading much of Ethan's wisdom, that I got as far as I did. The room has plenty of limitations on where to place treatment, or at the least limitations of because of how I want to arrange the gear. It would be difficult to place permanent treatment behind me when I'm mixing because of the doors and low ceiling. When I try to do any type of serious mixing, I plan to move the gobo's in behind me. Thanks for your input Ro!