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Hi Jon-
Well, here in New Zealand they do things a bit 'different' than back in the States, apparently.
I noted in your response to my recent 'Ping' that in reference to the corner bass trap SQ&E approach I'd like to use in my new Music Room, you made mention of lower R-value insulation having more 'paper backing' per roll and thereby being better at absorbing deep bass (which makes great sense), so I went to the local Bunnings and Mega Mitre 10 (NZ's versions of Home Depot/Lowe's) and discovered the bad news about fiberglass insulation rolls (or batts) here in NZ.
Apparently, the retailers here only carry fiberglass insulation that has NO paper or foil backing whatsoever. The plastic bags (or rolls) of insulation you can purchase here are simply stuffed very tightly with plain fiberglass in varying sizes, shapes and densities, but just fiberglass on the inside (and again, with a thin plastic bag cover that is VERY tightly fitting on the outside, BTW.) The bags are roughly 4' tall and between 15" to 18" in diameter, and feel very dense and heavy. (FYI-the bags are not exactly round cylinders, but more like a rounded rectangle shape, again about 18" x 15".) Can these be employed successfully as SQ&E corner bass traps? Any drawbacks?
The only insulation widely sold here in NZ that has any kind of paper backing is a type of 'wrap' that is employed for water heaters, but it is polyester batting that is glued to a somewhat stiff thin brown paper with foil on the exterior. I don't know if that will possibly work as an SQ&E corner trap, being polyester on paper/foil, and the diameter of the bags they come in are only 10"-12" (but four feet long, thankfully!) Also, the plastic bags they are packaged in are not really super-tight (like the VERY tightly shrink-wrapped fiberglass rolls described above), but only semi-tight (not loose, though), and have an open top that is gently twisted shut and only sealed with a zip-tie (although I could twist the top really tight to get a decent seal, then clamp it shut.) Also, the plastic bag cover for the polyester/paper wrap insulation is just a little thicker than the very thin plastic used on the fiberglass rolls.
I was hoping if the fiberglass insulation rolls described at the outset were not useable as SQ&E corner traps, that maybe the paper/foil-backed polyester rolls might be.
Of the two rolls, which would you suggest, if either actually will work?
Sorry to pester you, but I was pretty surprised that paper-backed fiberglass insulation rolls are simply not stocked here in NZ by any retailers.
Again, things are done a little 'different' in the land down under. :-)
Many thanks for your help and guidance. Really appreciated.
Cheers,
WS
Follow Ups:
Dear Jon-
I went back to all the various articles of yours that I have downloaded (a LOT!) and noted that you (and PeteW) previously stated that 'unfaced' insulation is fine to use for SQ&D applications. I assume this means no paper backing. Correct me if I am wrong, please.
That would simply leave the question of whether the polyester/paper/foil rolls (10-12" diameters) are better for low frequency absorption than the unfaced rolls of fiberglass (15-18" diameters). The other differences between the polyester vs the fiberglass rolls are:
1.) The polyester roll is not stuffed super-tight like it is going to literally explode outward if you slit the bag, but just nicely and firmly held in place. The fiberglass bags, on the other hand, are like over-pumped balloons that seem like they will blow open with a pinprick.
2.) The polyester roll is a nice, round 10-12" diameter; the fiberglass roll is more a rounded rectangle about 15" x 18". You can kinda squish the fiberglass to get it more rounded, but it takes a lot of force to do so, and it returns back to the original shape as soon as the pressure is released, so it really should be considered a rounded rectangle shape.
3.) They are the same height (approximately 48")
4.) The polyester roll's bag is a slightly thicker, more rigid plastic covering, while the fiberglass roll 's bag is thinner.
5.) They do not provide roll weights, but the fiberglass is over-all more weighty, while the paper/foil backed polyester has a denser feel to it (which is probably to be expected, given the difference in diameters and material compositions.)
6.) The polyester/paper/foil bag is not as well sealed (at the top, which is open and merely twisted shut) as the fiberglass, but the top can be firmly twisted shut and clamped tightly, giving it a good seal.
7.) The polyester is $57/roll, while the fiberglass is $90/roll. (At eight rolls needed --two rolls stacked per corner-- this is going to be a little expensive, but I am sure/hopeful it will be worth it.)
My guess is that you will suggest the fiberglass rolls as the best suited for SQ&D corner traps, but I am not absolutely sure, and thus this query.
I also thought maybe a mix might work well, with a fiberglass roll on the bottom and a polyester roll (if it is suitable) on the top in each corner vertical stack, or vice-versa, perhaps possibly offering some benefits versus fiberglass alone (assuming that the fiberglass rolls are what you will suggest as best for bass trapping.) Bad idea?
Lastly, they do carry here in New Zealand (at FAR greater expense) rolls of non-backed (unfaced?) fiberglass that are simply huge, like around 24-26" in diameter, about 40" tall. Is this too big, diameter-wise, or is more always better for deep bass absorption? How about (again) a possible mix in each corner? I am just looking for what will be optimal, trap-wise, given the options reasonably (but expensively) available to me.
Any assistance you can offer on these issues and queries will be greatly appreciated, Jon.
Again, a million thanks!
Cheers,
WS
Based on what you describe, the fiberglass rolls would probably work better than the foil/paper backed polyester.
However, they might not work "twice as well" with an eye toward the price differences.
The idea of mixing them might be a good one, that way, if one is partial to certain frequencies, and the other to different ones, they get spread out a bit by using one of each in each corner.
The huge rolls of fiberglass WILL probably work even better, but they would be more applicable to deep bass, and the cost probably wouldn't justify the slight increase in actual perceived sonic performance.
Remember, when using the SQ&D bass traps, they operate on sheer quantity
of absorbing material, and how much is crammed into the roll (density). Added membranes that are layered inside the roll can add to deep bass absorption, but depending on how much compression is present, they may not add that much.
Jon Risch
Thanks, Jon. I'll definitely apply your thoughts and logic on the SQ&E corner traps issues.
The carpeting quest is becoming really depressing, however. And while I know you previously admonished me that carpeting was not your audio forte, any help here would be appreciated.
Here in New Zealand, any substantial, nicely plush nylon static-free carpet will cost around $7k to $8k, installed with 11mm underlay (padding.) A moderately plush nylon has been wrangled down to $5500, same particulars. Thin/short/tough cut-pile nylon can be had for around $3400-$3800, same particulars, but it really is low-profile and pretty tight to the touch, and not much there. Only the ridiculously expensive stuff seems nicely absorbent, plush and plentiful. Ouch!
Having re-read your original answer a number of times, and done many Google searches, for sonics in a Music Room it all really boils down to how thick the carpet and padding are, and is the carpet static-free. However, in NZ, for some reason it is very, very hard to find any green colored carpets, except in wool (seriously here; I am not joking. Kiwis, apparently, are damned sick of seeing green all around them, and want anything but in their lounges and homes, generally speaking.) And wool carpets here are thin, period. Like the $3400-$3800 nylons mentioned above (although the wools are somewhat dearer, about $4200-4500, same particulars.)
I adore green, and especially green carpet, and find it the most relaxing color imaginable. The only really nice greens (unfortunately) are in the wool carpets, and a few decent greens in the super-expensive American nylons (but not as lovely as the colors available in wool; apparently wools take the dyes much better than nylons do.)
And so here is my query:
If I lay down a pair of nice long strips of thick Sonex (3" H x 16" W x 6-8' L) on the carpet between the speakers and my listening seat, do you think I could maybe get away with a thinner wool carpet (which aren't static-prone, I understand), without having to spring for the super big-buck thick-as-hell nylons? As previously stated, the wools are thin, like the $3400-$3800 nylons, but the colors are simply wonderful! Deep, restful greens in rich tones. Very lovely. Same cut-pile style, same really thin, low profile as the el cheapo nylons. Just a little more expensive, but spectacular colors. Way deeper, richer colors even than the mega-buck nylons (but a few of the expensive American nylons are decent, too.)
If you think it would be significantly deleterious sonically to go with the low profile, low weight carpets, even with the Sonex strips laid down, I'll bite the bullet. But before I do, I'd like to ask what frequency range do you believe would be most effected by a room laid with shorter, less weighty (most likely wool) carpet, versus tall plush cushiony (nylon) carpet?
(I listen exclusively to digital sources, BTW, however that impacts the sonic equation.)
A million thanks, Jon. These are fairly expensive decisions I'll have to live with a LONG time, both visually and sonically, and thus my trepidation and request for any guidance you can afford. I fully understand you don't consider yourself the AA carpet maven, but any input is sorely welcomed and greatly appreciated. Again, many thanks!
Cheers,
WS
Strictly from an acoustics standpoint, a relatively thin carpet and a decent thickness pad (not super thick, not super thin) should be fine.
The thickest deepest plush carpet and the thickest most sound absorbent pad together will really only significantly affect frequencies above about 5-6 kHz, with some effect down to about 2-3 kHz, depending on the particulars. Typical middle-of-the-road carpet and pad would likely double those frequencies.
Yes, use of Sonex strips (or better yet, a simple rectangle placed at the first reflection point) will do much more than the very best carpet/pad combo.
Keep in mind that you can always put down a throw rug or a plush rug or "Persian rug" at those locations later if the sound is too bright and you have too much "floor flutter", and the Sonex is not acceptable long term.
What about your ceiling? That will have an effect too, and will partially determine what you can get away with on the floor.
One more thing to ponder, is that I have heard some rooms with hardwood floors (albeit with a rug in line with each speaker) sound pretty good sonically, as there was enough attention to detail everywhere else.
However, concrete or other hard dense floors are not quite as forgiving as a hardwood floor over the typical wooden house floor framing.
Good luck on your project, and I hope the room turns out wonderful sonically.
Jon Risch
Thanks, Jon, for the detailed advice.
Regarding the ceiling, it will be all 5/8" spruce interlocking (dove-tailed) panel-boards, stained and then screwed into place, mounted on 5/8" drywall gypsum board. The gyp board will be a softer variety, and will be the same type we will employ on the walls, as well.
Something I have instructed my builder to do, is to employ a type of damping foam strip on top of all studs (between the studs and the drywall) so as to absorb as much energy into the walls as is possible, toning down the drumhead effect as much we can. The same will occur with the spruce ceiling. The sealing glues for the edges of the drywall intersections on all walls will employ a material that is used for sound damping that does not dry hard and rigid, but somewhat pliable to, once again, absorb as much energy as possible.
Thank you for the kind wishes about the ultimate sonic character and performance of the listening environment. Of course, we are all keenly aware of the 'best laid plans' going awry, but I am hopeful things will turn out sonically decent. One never knows, though, until that first burst of music issues forth, and until then, one can only cross one's fingers and hope long and hard that things turn out fine.
Thank you so very much for all your kind and thoughtful assistance, Jon. Your advisements will guide me and my builder, are invaluable to us, and again, are so very much appreciated that words cannot do justice to our feelings of gratitude for your time and efforts!
Cheers,
WS
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