Sidewall acoustic treatment DIY
For my latest installment in my monologue, I thought I would share some of the ideas I am using to construct acoustic treatments. I am no expert in this matter, have read a fair amount on the forum, have watched the acoustics 101 home theater geeks numerous times, and have decided to to take my inspriation mostly from Anthony's guidance on that HT geeks video. Perhaps at some later data, I can revisit more with either more $$$, eperience or fine tune with a professional calibration, but I want to keep moving and attack this with some trial and error.
So - onto my approach. I am using the ~20% absorbtive and ~20% dispersive baseline as my design input, for a given wall. I am creating the treatments somewhat centered in height at ear level, and then leaving untreated areas at the floor and celing to allow for some more refleeections for ambience. I will be treating the entire area you see here between the screen and the vertical strips near the white light can with the same black velevet as the ceiling area for maximum light absorbtion. I understand that this material will absorb some high frequencies (how much, no clue) so I am keeping the amount of absorbtion using the linacoustic to < 20% for this reason.
FOr absorbtion I am using 1" linacoustic, for 2D difusser I am using some of the same plastic Screen TIght channel cut into strips and installed strangely (more on that in a minute) and then some wooden 3/4" thick pine cross section strips that I found at Lowes which are designed to be used to seal off the end of metal roof panels.
Here is a look at the basically finished product on the front right wall, which will all be covered next with black velvet:
A little in reverse order, but the basic construction here is as follows... I need to hide 1" thick linacoustic behind the black velvet wall covering, and I did not really want to get into making tons of fabric wrapped panels and then figuring out how to properly hide fasteners or come up with the needed friction fit to keep all in place. So, of course, I gravitated back to my favorite plastic Screen Tight track again. This track is just over 1/4" thick, so I need a 3/4" material to space this track out from the wall surface. For that job, the options are slim for 3/4" sheet material - MDF or particle board (which might as well not exist in my book as a horrible product). MDF it is! Installed the MDF to the DW/OSB layer using 2-1/2" screws, then installed the track to the MDF using a mix of left over shorty screws. MDF was ripped roughly at Lowes to a wider width to keep all the MDF dust at Lowes, then I just made sure to install the track straight on top of the MDF. Note that I am now using the wider 3-1/2" Screen TIght track as a base mold and as the pillars of a column eventually under the white light can in the soffit above. This column will be BLACK (I think) anchorage GOM.
Here is a shot showing more of the construction phase before I had these random ideas for the diffusers:
This is just pieces of linacoustic cut to dimensions as I calculated and then attached to the DW/OSB walls using 1-5/8" DW screws installed into some roofing cap nail plastic washers to keep this tight against the wall. Remember, I want this all to be invisible once the velvet is installed into the track, just like the ceiling.
Call my crazy, but i like this plastic track. Maybe i have used it too much or stared at it too long, but i got to thinking about using it itself as a diffuser as it has interesting edges, is thin, and could help scatter. Then, I thougt about forming a 2D shape, like I (think) I saw in the HT geeks episode. So, I cut the track into short pieces that included (3) of the precut holes for installing the track. I installed one screw, then marked the center hole location on the DW, rotated the track out of the way and then installed the screw UNDER the track, then, bent the track back down against the wall for the 3rd hole. I then adjusted the depth of the middle screw (thru the slotted hole in the track) such that peak of this bent profile is under the plane where the velvet will be eventually. Repeat many times.
I have seen many cool 2x4 cut patterns glued or screwed and then painted onto a 2x2ft panel. WHile I would love to get rid of my 2x4 scraps, I just do not want to have something that obtrusive in the room, and especially on the side wall of my somewhat narrow room. Needed something <1" in depth and this wooden profile I found seems to be perfect for the job. Not too expensive (couple bucks for a 6ft piece I think) and it allows for easy staggering upon installing. I elected to stagger this in a brick pattern, and used a spacer (you guessed it, another cutoff piece of the 1-1/2" plastic track) to spread this out to allow the bare wall surface to also form a cavity between the wooden strips. It certainly looks cool, and I hope it performs the job. Too bad it will not be seen as it looks interesting - but glad i dont need to paint...
So - next i plan to install the velvet over the bottom "panel" and see how it looks. I think the wide 3-1/2" plastic track, once covered in velvet, will look neat as the base molding and then the narrower 1-1/2" caps between the panels should give a nice finished "panelized" look witout the need to make a bunch of panels. As I said, for the remainder of the wall I plan to use various dark and gloomy colors of the GOM Anchorage fabric to allow some character to creep in to the room. Rest assured I will be asking advice on that one next...
So let me know your thoughts - am I way out in left field?