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Post by kcatthedog on Jan 17, 2015 16:06:41 GMT -6
I know Jk had a thread here somewhere but I couldn't find it. I have done a fair bit of research but roxul safe and sound has really good coefficients and they make a product called Comfort board, semi rigid not batt 2x4 pre cut sheets I made some 2x4 frames from 1x2 pine and put 3/8th wafer board backing on them glued and nailed, then just placed 2 pieces or 3 of the comfort board and wrapped them in cloth and stapled from back; quite easy actually I used a piece of the 1x2 as a mount, screwed that into the wall at the bottom and sit the panel on that to take the weight and just have one drywall screw at top to hold it in place you could mount an inch or so off the wall and it would absorb deeper freq too like so ! Attachment DeletedAttachment DeletedAttachment Deleted |
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Post by Calvin on Jan 18, 2015 16:07:00 GMT -6
Awesome, I like it! Question, does the 3/8" backing board cover the entire rear of the panel? If so, are you concerned that the backing board will limit the panel's ability to absorb lower frequencies? I'm completely unfamiliar with comfort board, but I'm going to look in to it due to your post. Thanks!
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Post by M57 on Jan 18, 2015 17:55:05 GMT -6
I've been told by a manufacturer that unless you're going with 4" - there's not a big advantage to open backs. Can't say that makes a lot of sense to me. I would think that the deciding factor would be distance from the wall/ceiling, not the thickness of the absorbing material. If you're not creating more than 3 or 4" of space behind the panel, then there's no reason not to have backs.
Anyway, isn't that the point of using semi-rigid? ..that you don't have to have backs?
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Post by kcatthedog on Jan 18, 2015 18:06:34 GMT -6
Awesome, I like it! Question, does the 3/8" backing board cover the entire rear of the panel? If so, are you concerned that the backing board will limit the panel's ability to absorb lower frequencies? I'm completely unfamiliar with comfort board, but I'm going to look in to it due to your post. Thanks! Good question. I think unlikely as the 3/8 material is i think a paper composite material with little mass so i don't it can reflect much mid to low freq energy ? If anything it might slightly attenuate certain freq more than others. I will probably move them off the wall 2-3 inches to lower the freq they absorb. Other option would be to but@y the black or white shelving planks with one good rounded edge have them rip it down to 4-6 inches and use that to make a tight 2x4 interior measurement frame and stuff it with roxul batt with a layor of comfort board on front for nice clean plunb plane. You could run two bands of the 3/8. X 4 inches to prevent the batts from moving out the back and in effect have open back absorbers ? These are not expensive so trial and error works and you always end up with a good mid to high bsnd absorber Bass traps are best in corners anyway wall snd cieling floor wall not so significant ! Good luck ! |
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Post by kcatthedog on Jan 18, 2015 18:13:26 GMT -6
Ps i had made these frames sonetime ago with just obe layer of comfort board so needed the back for it to rest on.
I have also made absorbers from stryrofoam board cut about 5 inches deep to make the box. I glued and screwed these together and used L brackets to hold them in place.
Tthey are the floor to cieling bass traps you can see in back of my room .
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Post by svart on Jan 18, 2015 21:15:35 GMT -6
Having solid wood panels on the backs keeps the absorbers from working at lower frequencies. Attenuating low frequencies requires distance and/or mass since low frequencies have more power than high frequencies. Having a hard surface directly behind the material is the same as mounting it on the wall with no space behind it.
Most manufacturers want their panels mounted 1-4" away from the wall to work the best, but this means they should be open in back so the low frequencies get attenuated by the density of the mineral wool once as they pass through, again travel through the air gap, then again as they bounce off the wall behind(and scatter slightly) and finally they are attenuated once again through the panel. This is a proven phenomenon and a primary tenet of acoustical engineering.
What I would do here is cut a large opening in the back, then staple cheap burlap over the hole while pulling it tight. The burlap will support the soft mineral wool while the wood frame is the mounting point.
What I actually did was to take 1"x4"x48" boards and route the side so that there was a long opening along the board. I used these boards as the sides for boxes for the soft mineral wool. I simply stapled cheap burlap to hold the mineral wool inside the box and then covered the front and sides with decorative speaker grill cloth. On later ones I was able to get burlap that was nice enough to do this in one step.
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Post by svart on Jan 18, 2015 21:23:25 GMT -6
I've been told by a manufacturer that unless you're going with 4" - there's not a big advantage to open backs. Can't say that makes a lot of sense to me. I would think that the deciding factor would be distance from the wall/ceiling, not the thickness of the absorbing material. If you're not creating more than 3 or 4" of space behind the panel, then there's no reason not to have backs. Anyway, isn't that the point of using semi-rigid? ..that you don't have to have backs? You're right to be skeptical. All panels work better without backs and with an air gap, or more thickness. A 2" panel with a ~2" gap will work roughly as well as a 4" panel against the wall, and so forth. It's not exactly a 1:1 type of situation, but you get the point. Semi-rigid and rigid are nice because you can essentially glue the covering to the panel without a frame. Mounting still takes some care, even with fully rigid panels. I've accidentally torn out the mounts from not being careful more times than I can remember. |
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Post by tonycamphd on Jan 19, 2015 0:58:34 GMT -6
A 4" deep panel against the wall works better than a 2" deep panel 2" off the wall.
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Post by M57 on Jan 19, 2015 5:35:33 GMT -6
A 4" deep panel against the wall works better than a 2" deep panel 2" off the wall. No doubt this is true ..but do those 2" of air behind the un-backed 2" panel have significant impact? ..say vs. 2" air behind and un-backed 4" panel? I didn't think to grill the sales person on the subject, but his implication was that space behind the thinner panel is not as much a factor because the the thinner panel isn't absorbing lower frequencies as effectively. Hmm. now that I put it that way, it does make a certain amount of sense. |
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Post by tonycamphd on Jan 19, 2015 9:29:02 GMT -6
Having the air gap space behind any and all panels makes it more effective, especially down low. thickness and depth with an air gap or not, is always more effective, especially down low.
ex
1" set 1" off the wall is better than 1" set on the wall
2" set on the wall is better than 1" set 1" off the wall
The sales guys logic seem flawed, yes thicker is better for low freqs, but 1" set 1" off the wall is better at absorbing low freqs than 1" set ON the wall.
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Post by kcatthedog on Jan 19, 2015 10:05:18 GMT -6
Opening backs and bringing off wall make sense to me: thx Svart !
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Post by tonycamphd on Jan 19, 2015 10:13:52 GMT -6
also mounting them at a single point so they can move freely actually helps them dissipate energy, a hard fasten acts as a coupling which is less effective.
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Post by Deleted on Jan 20, 2015 0:05:41 GMT -6
I think my GK panels were made by building a 1x2 frame that the insulation actually sits on, not within, then stacking the panels upon the frame to 4" thick and then clipping and folding the aluminum edging for corners on sheetrock and then wrapping the whole thing in burlap. I should have built them. Of course, there is some glue holding things together.
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Post by kcatthedog on Jan 20, 2015 14:57:57 GMT -6
I may hang them from the ceiling 4 inches off the wall ?  |
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Post by kcatthedog on Jan 24, 2015 17:05:17 GMT -6
Ear trix ? so I have been cutting out the backs of my 2x4 x 4 inch panels and placing them about 4 inches off the wall now seriously I have done only two and I turned on some music and things sound significantly more precise I am listening to a sort of modern jazz rock track and the snare sounds just like I am inside it where as before it didn't have this finesse at all would you think opening the backs would make that much difference ? also, since I am remounting the panels I could put them higher up the wall closer to the right angle with the ceiling which would theoretically be better and I could offset them more against each other on opposing walls to reduce flutter echoes etc. what do you think ? Attachment DeletedAttachment Deleted |
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Post by M57 on Jan 25, 2015 5:50:08 GMT -6
Here's the before pic, which I've posted previously. I recently moved into the new space and started to record some BVs for someone else's project a few months ago. They sounded horrible, and I knew it was going to be a disaster before I even listened to the first take. I had to trash the session and I haven't even tried to record in the room since.  It's almost finished now, but I can't help but wanting to share. Ripped out the rug, put in a floor, installed a second window inside that big ole honkin' street facing window, and just yesterday I installed a bunch of 2" panels on the 45, ceiling and other primary reflection points (Up/L/R) They are flush mounted so I went with backed panels, which made the install much easier, and though I cut corners by not going with 4", especially on the 45, I hedged my bet by going with the heaviest Roxul product @ 8 lbs/cu ft. I still have to assemble a few more 4'x2'x4" (unbacked) traps that will go in the corners, and I'll have a few left over to use as gobos. I have to say, the row I put on the 45 makes a HUGE difference, not just in the listening area, but in the room in general. The room is just better sounding from any location. Now anytime I say something while facing sheet-rock, I cringe. I can't wait to give the BV session another go.  |
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Post by kcatthedog on Jan 25, 2015 8:07:07 GMT -6
nice and the smaller monitors are wise in terms of bass energy in a smaller room.
I bet you wil be very pleased; good work and nice space !
if you have an extra $75 bucks I recently got the isoacoustics stand decouplers and they are significantly better than the foam and allow you to angle too
if you go on their site you can identify your monitors and they tell you which model you need.
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Post by M57 on Jan 25, 2015 8:44:18 GMT -6
nice and the smaller monitors are wise in terms of bass energy in a smaller room. I bet you wil be very pleased; good work and nice space ! if you have an extra $75 bucks I recently got the isoacoustics stand decouplers and they are significantly better than the foam and allow you to angle too if you go on their site you can identify your monitors and they tell you which model you need. Thanks! Yeah - I've actually been considering those. For one, the speakers are two low - I keep having to hunch over to get my ears at tweeter height. But also, I can feel them vibrating right through the desk. I know I need to do something. |
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Post by kcatthedog on Jan 25, 2015 10:11:30 GMT -6
definitely the best product I have tried so far and I flipped my adams upside down to get the tweeters aimed up at my ears :0
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Post by tonycamphd on Jan 25, 2015 10:56:35 GMT -6
definitely the best product I have tried so far and I flipped my adams upside down to get the tweeters aimed up at my ears :0 I'd Flip those back over, and get the height right for a proper image bromee, when do hi freq come from underneath the bass? In my world never. If ur trying to work outside the speakers when u mix(and u should), bass should hit the floor highs hit the ceiling. This flip makes ur job harder IMO also I recommend never laying your monitors on their side, phase issues when you move around. I'd also mount those panels to take out direct reflections from proper monitor level, raising them up to reach a corner and opening straight slap back reflection is NG |
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Post by M57 on Jan 25, 2015 11:39:00 GMT -6
definitely the best product I have tried so far and I flipped my adams upside down to get the tweeters aimed up at my ears :0 I'd Flip those back over, and get the height right for a proper image bromee, when do hi freq come from underneath the bass? When the drummer is playing upside down? When the tire noise is below the rumble of the engine? When the engineer is standing on his head? Ok, not often, but does it really matter? Can your ear distinguish placement of a vertical driver configuration? Horizontal, sure.. but vertical? I'm pretty sure I can't tell the difference. My ears sit on the sides of my head. Direct sound hits them at identical times if the drivers are equidistant with the flip. And given all the material that's eating away at primary reflections, I don't see how that would betray an upside down speaker - not that I'm gonna flip mine. They easily passed the mirror test (including the overhead cloud) with a foot to spare given the projected speaker height, and the overhead cloud is only 3" from the 120 ceiling wall corner. Where is the slap back? The little bit of exposed sheet rock direct sound hits at the top of the 45 ricochets across the room to the other opposing 45, which is not treated, but angles the sound down from there. There are actually very few parallel surfaces in the studio as a result of the ceiling angles. But now you've got me thinking - The most likely troubling reflection point is the desk itself. If I keep the speakers lower, and angle them up, that might help a little - but I'm not sure. |
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Post by tonycamphd on Jan 25, 2015 11:50:47 GMT -6
I'd Flip those back over, and get the height right for a proper image bromee, when do hi freq come from underneath the bass? When the drummer is playing upside down? When the tire noise is below the rumble of the engine? When the engineer is standing on his head? Ok, not often, but does it really matter? Can your ear distinguish placement of a vertical driver configuration? Horizontal, sure.. but vertical? I'm pretty sure I can't tell the difference. My ears sit on the sides of my head. Direct sound hits them at identical times if the drivers are equidistant with the flip. And given all the material that's eating away at primary reflections, I don't see how that would betray an upside down speaker - not that I'm gonna flip mine. They easily passed the mirror test (including the overhead cloud) with a foot to spare given the projected speaker height, and the overhead cloud is only 3" from the 120 ceiling wall corner. Where is the slap back? The little bit of exposed sheet rock direct sound hits at the top of the 45 ricochets across the room to the other opposing 45, which is not treated, but angles the sound down from there. There are actually very few parallel surfaces in the studio as a result of the ceiling angles. Ur room looks much improved, if u could wanescote the walls in wood ud be stunned. The slap back was referencing kcat, as far as the monitors, yes ur ears certainly can hear the diff, they are beyond sophisticated, they are very sensitive to direction, especially at close prox, and sound waves propagate out of phase upside down(see tweeter offset) they design them right side up, why screw with that? |
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Post by svart on Jan 25, 2015 11:55:29 GMT -6
It may not be that the drivers need alignment, So much as some tweeters, especially ribbon tweets, exhibit a phenomenon called "beaming", where frequencies are coherent and do not disperse properly. Any tweeter with a flat radiation surface will show this.
Adams are prone to this and aligning the tweeters with your ears are a partial fix for this.
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Post by kcatthedog on Jan 25, 2015 15:42:34 GMT -6
sure Tony I keep experimenting
you mean the ones to each side of mix position raise them so they are flush with ceiling; don't quite understand this direction ?
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Post by tonycamphd on Jan 26, 2015 15:32:01 GMT -6
sure Tony I keep experimenting you mean the ones to each side of mix position raise them so they are flush with ceiling; don't quite understand this direction ? I'm just imagining you lifting them up toward the ceiling in an effort to trap the corner? which is a good idea, but not at the expense of having direct reflections coming back into a mic or ears because you raised them too high? if that makes sense? I may be mis understanding. |
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