Bass Traps: Just keep INSULATION roll sealed in plastic WRAP? - AcousticsInsider.com

[@warpacademy]

As @Hamachingo said, leaving your insulation in bags will be compressing it. In the case of rock wool, it's mild compression. With lower density fiberglass, it's fairly extreme compression. Compression, increasing the density of the treatment will change its gas flow resistivity / acoustic properties in a negative way. As said in the video, if building traps is holding you up from treating your room, putting full bags of insulation in there is better than nothing. But it's not the same as properly installed material. Edit: Here are the facts. Rockwool Comfortbatt R22: Packaged height: 19.75". Uncompressed height: 27.5". It expands to 1.39x the packaged size. This is a substantial difference. It's even more when you're working with fiberglass. Packaged height: 18". Uncompressed height: 96". It expands to 5.3x the size.

[@warpacademy]

@fartpooboxohyeah8611 I think it's better to look at the data. Here are the facts. Rockwool Comfortbatt R22: Packaged height: 19.75". Uncompressed height: 27.5". It expands to 1.39x the packaged size. This is a substantial difference. It's even more when you're working with fiberglass. Packaged height: 18". Uncompressed height: 96". It expands to 5.3x the size. Using the porous absorption calculator to demonstrate the effect of compressed material inside plastic is also questionable. If you can't blow through a material, you can't accurately model it using porous absorption calculations. I get where he's going with the video though. If your choice is between doing nothing to your room, or adding in insulation in bags, then the stuff in bags will move the needle a bit. But it's not accurate to say that leaving it in the bags makes almost no difference; it does.

[@borey123xx9]

So im confused, is it better to compress rock wool or leave it be when making bass traps?

[@MuzdokOfficial]

@@borey123xx9 uncompressed

[@nashbeuh]

Good point! That's what I did on the back wall of my room (1,5 meter thick) and it worked very well! For reflections above 1K just let hang a curtain in front of your stacked, still packed Rockwool. Easy, fast and efficient.

[@rikardekvall3433]

Any room for you and speakers?😀

[@nashbeuh]

​@@rikardekvall3433 😂1,5m is the thickness of the rockwool I stacked at the back of my basement, bunker style room, with a pair of ATC SCM 100 ASL PRO.

[@Hamachingo]

Most of the fluffier insulation materials made to be stuck between studs have some sort of membrane on the front and back, to keep the fluffy in shape. In practice I found this actually helpful as long as you don't put many panels behind each other in a panel, but be aware that it's better to pack two 100mm panels behind each other to get a 200mm deep absorber than to stack a four 50mm ones. Had some packs of TP-1 in the corner and experimented around with REW. Pulling them away from the corner a bit improved bass absorption considerably (almost half the Hz) but orientation made a noticeable difference in the mids (I assume the membranes act as a kind of waveguide), I could literally turn the pack and watch the peaks and valleys in the 3-6 kHz range even out. Unpacking everything did not measurably change performance (changing orientation still did though) but my room was already well (over-)treated treble range ad that point.

[@aristotle_4532]

Any membrane improves the bass absorption and there is no real loss in high frequencies. Fabric offers massive improvements in absorbers and even more improvement if the weave is dense. Always measure large samples with fabric and all layers in final position outdoors and away from the ground with a good replacement for the wall. Impedance tube measurement of fabric is completely useless, material measurements in isolation are massively misleading and models are downright funny. No scientist tries to predict behavior in real world applications. They always test the final combination and experiment in very large sizes.

[@Hamachingo]

Consider this: 1. In the original wrapping, the material is generally compressed a little bit by the high packaging, so you're getting higher density and flow resistance than advertised. 2. the plastic wrap keeps the moisture from getting in and out so mold can grow there very easily, especially if it's right against a wall.

[@warpacademy]

^^^^^ this. Very important considerations.

[@jonlanghoff]

Thanks for a nice short-but-sweet vid, and it’s good news for me, since I’ve already stacked Rockwool from floor to ceiling on the entire front and rear wall in my basement listening room. In terms of the ugliness, I’ve chosen to install a gray velvet curtain, which as a bonus should also deal with whatever higher frequencies that might otherwise have been reflected by the plastic wrapping around the insulation material. 1st and 2nd reflection points are dealt with via some free-standing GIK panels, plus some thick foam on the ceiling. Next step is probably to add some diffusion technology into the room, since it’s now a little bit on the “dead” side. So, “diffusion in small rooms” is my next topic to investigate! :)

[@rist98]

Doesn't the wrapping material essentially make it into a pressure bass trap? Like, the plastic acts as a membrane for the bass frequencies to try and push, and the physical movement of that pushing and pulling by the sound, is then transferred into the foam, and thus absorbed. (Havent watched the full vid yet, but it seemed to me that he didn't consider this angle in this vid)

[@crystalfunky]

Sehr gut. I wrapped the mineral wool in my panels in very thin plastic, so I don't have to worry about my health. And the panel still does the job perfectly!

[@bunny.bunbob]

Finally somebody talks about this

[@mpitogo1978]

I’m trying this as a shortcut for now. I bought 12 bags (2 pallets) of 23”x47”x3” rockwool.

[@KarlGutowski]

Most Corning fiberglass products have a flow resistivity of 4700. Roxul AFB and Safe N' Sound at 3" thickness has a flow resistivity of 16600.

[@stevedemetrious6454]

I’d love to see you do a video on limp bag traps. The same type John Brandt highly recommends and uses in his studio designs.

[@G_handle]

Okay so this has been in my head for literally over a decade. I bought a dozen packs of Safe-n-sound for a friend's garage studio, which we gutted. I shot the room w REW completely as studs just to compare along the way. We brought the insulation (and wood) in just to store overnight, and in the morning I decided to shoot it again With all the insulation in its bags staked across the back wall. The top end was similar but the bottom end was totally different. My boy was excited and we finished the build, and it was great for his needs. But my question has been ever since: why not frame in the corners to hold the bags in stacks without opening. The plastic shouldn't be touching the lows I'm trying to absorb. And maybe the increased density is actually Helping, catching lower frequencies? So question for you, What do you think about this strategy: 1) temporarily hang furniture blankets everywhere to slow down high frequency reflections just for testing. 2) stack as many bags of SnS until the lows are under control. 3) place panels in the obvious reflection zones 4) start hunting rogue reflections targeting specific problems in REW. Obviously an oversimplification, but my basic strategy.

[@caspermaster-com]

That should be fine, and even great to my knowledge. If I build a room again, I would probably just do this. Build the frames and planning around just sealed rolls and then add high freq absorption to the first reflection points. Also to add, the bales are rounded and will probably be good for diffusing the highs too. I have my spare rolls in the front corners behind my custom large side panels. Also because the subwoofer is close to those corners, it's nice to further deaden the bass there

[@alexh8754]

i beleive if the increased density does not help. increased density may reflect low frequencies

[@warpacademy]

Best to first do research into the acoustic properties of the materials you're using. The assumption that increased density is better for LF absorption is actually dead wrong. Higher density material can work for very thin panels, such as Primacoustic pre-fab ones, but not for larger, thicker custom absorption. It's most common to use mineral / rock wool in broadband absorbers, but it looses some effectiveness when compressed (such as in plastic bags) and it also looses some effectiveness when the trap is thicker, such as in your RFZ corner points in the front of your room. For that reason, we use a combination of rock wool with lower density fiberglass behind it. This is superior to an air gap and superior to just using straight rock wool. DO NOT compress your acoustic treatment or use higher density material; it changes the acoustic properties for the worse.

[@SashimiSnow]

@@alexh8754 exactly. It does. That's a fact.

[@fsync]

I think you're bang on (and explained it well). I have these rolls lying around and was wondering if i can quickly test before the massive effort of carving panels.

[@zootook3422]

My Rockwool expanded to about 170% or more after unpacking.

[@kennylux]

Thank you so much for actually putting out the pdf guide for free, you're the goat

[@duanemiles2044]

Where can I find flow resistivity values for various materials? MDF OSB, plywood, fiberglass, rock wool, sheeps wool, etc? Even ballpark numbers.

[@youtubewatcher2006]

Since all commercially available acoustic panels come without plastic wrapped around the filling material, is it possible to just wrap the entire panel with plastic from the outside? Just a super thin painters tarp.

[@neaumusic]

making a cheap shelf 7x7 by 1ft deep with all vinyl cubes full of loose fill, right where the first reflections are at the back wall (my couch), pretty stoked because loose fill is only 0.5 pcf, just hope it isnt too low. I also know that it can be packed denser, but everything I read says size and low density is best

[@Marcin79W]

What would be the best idea to protect panels from releasing fibers? I guess one layer of pallet wrap film wouldn't be a problem causing much reflection. Thank you for the video.

[@RaytownProductions]

Literally was considering this two days before this video was release. Beautiful timing Jesco. Appreciate all you do for us home studio folks! 🤘

[@MrSplit57]

Hi, thanks for the video! You are actually addressing my biggest concern - micro fibres from mineral wool contaminating the indoor space. Please confirm do I understand it well: Can I wrap and seal mineral wool package with some plastic bag or strech foil and have the same, or almost the same bass damping effect?

[@DmitryMyadzelets]

I tested mineral wool panels hanged under the ceiling, without and with wrapping them with polyethylene kitchen foil (it lasts for thousands years), with no pressure appled. The wrapping decreases little only high frequency adsorption.

[@jakelondon]

Question: Would single bat of insultation, like the one in this video, make a meaningful difference on controlling bass (under 180 hz) in a cluttered smallish room (12.8ftL*11ftW*8ftH)? I've already got 4 16in*49in absorbing panels in it, which have made a meaningful difference above?

[@zerobject]

A bit offtopic, but would highly appreciate a dedicated video on active bass trapping technologies. Can we consider it an alternative or rather an addition to passive methods? Lots of controversial info around, as usual.

[@MrTeff999]

I’m curious about how effective other materials are. Especially fiberglass insulation, which is so much cheaper.

[@fb8966]

Density: the air gaps reduce sound transmission as they do heat transmission..... Is denser better? and plastic membrane stopping the air vibrations from hitting the rockwool.... Test results please.

[@FredDeMassiveAlambic]

Currently building first acoustics treatment all based on your words, and I chose to make a plastic wrap around Rockwool, with another thinner layer of polyester fiber to get rid of plastic reflections. Can't wait to hear it, and just wanted to thank you for all the good advices.

[@somedood6621]

Same question but how effective would kingspan thermal insulation panels be? I have some and am wondering if its worth keeping around, Thanks

[@kingtubbyleeperry]

Great video Jesko.

[@Ceko]

So what I understand of the basstrap in your graphs is that they absorb almost everything from 1000Hz onward, is that correct? Won't that effect the liveliness of the sound?

[@darionjaikaran4180]

Hey guys beginner at acoustic treatment here. If I had a room that was permanently dedicated to mixing, would it make sense to simply build panels that covers the entire wall and pack rockwoll into that?

[@gonzalobarreiro3990]

These videos are just great, question which is the best rock wool densitiy for absortion panles? The higher the better?? Thanks!

[@christianraabe6669]

Hey Jesco Danke für die Videos. Gibt es den Guide auch auf Deutsch ? Ist für mich einfach bisschen verständlicher 😁

[@m76353]

AWESOME!!!!! i was really curious about this!!!!! great video thanks!!! just subscribed!

[@ColocasiaCorm]

Wait why arent we compressing rock wool? Saves space and increases densiy.

[@DmitryMyadzelets]

I tested mineral wool panels hanged under the ceiling, without and with wrapping them with polyethylene kitchen foil (it lasts for thousands years), with no pressure appled. The wrapping decreases little only high frequency adsorption.

[@roy-yal]

How high frequencies did it reflect? Does the plastic wrapping have and effect on the midrange lets say (1k-8k)?

[@giacomoneri1782]

If sealing the rockwool only affects highs response, then you could solve the high end reflections by adding foam on top of the plastic wrap. Also, would it be a good idea to seal the bass traps with rubber or silicone thin sheets? It would also make it much easier to clean, as you can get the surface wet or vacuum it without pulling the fibers.

[@DmitryMyadzelets]

@levibalint3253 If need data I can look for my measurements

[@roy-yal]

@@DmitryMyadzelets i’d be curious

[@DmitryMyadzelets]

@@roy-yal I've searched over all my measurements and have finally found it. So, the test setup was as follows: A room 3.0x3.5 meters, 3.5 meters height (S=10m2, V=36.75 m3). Given the materials the calculated RT was 1.28 sec. A square absorption material (0.6x0.6x0.1 m) was hanged in one corner (0.3 m distance from the walls and ceiling). This material was then wrapped with a polyethylene kitchen foil (1 layer with some overlapping). At each step three measurements were done with REW, the results of RT60 are averaged: 500, 1000, 2000, 4000, 8000 // Frequency, Hz 0.81, 0.81, 0.68, 0.61, 0.51 // RT60, sec / No absorber 0.68, 0.68, 0.61, 0.57, 0.48 // RT60, sec / Absorber with no foil 0.67, 0.67, 0.63, 0.58, 0.48 // RT60, sec / Absorber with food foil The measured RT with no absorber was 0.72 sec (which is less than the calculated 1.28, due to presented furniture). With 4 square absorbers the RT went down to 0.49 sec.

[@saardean4481]

Have you tried or is there any testing of building bass traps using compressed Hay-straw? I mean compressed it is pretty dense and its a non toxic material?

[@FdUpNews]

Just what I needed, great guide. thanks!

[@abdo-dr1tu]

Hello! I’m a little confused, if the package is wrapped by plastic then the material is not really having any surface area to interface with air of the room. In other words, Air is not flowing at all.

[@PatrickDuncombe1]

Here's how I understand it: sound is to do with air pressure and not air flow. Pressure outside the plastic can obviously act on the plastic itself - pushing it in or out. The plastic's flexing changes the volume of air inside and therefore the pressure inside. That way the pressure wave can pass through. You can think of the sound as inflating and deflating the bag, essentially.

[@jackedkerouac4414]

I'm with you on that. I managed toy and cosmetics factories and believe me packing material plastic is always the cheapest, most mass produced we can get. Surely it's less than ideal to keep it wrapped

[@almightytreegod]

It's about air pressure, and it's basically acting like a spring to slow down the movement of air particles inside and outside. That's why they make membrane traps as well. It's kinda sorta the same idea as a membrane trap, except that plastic is so thin and almost acoustically transparent so it's more like having next to nothing in the way, except of course with high frequencies, which are much easier to stop.

[@KingOath]

Do the test he said. Put thin plastic infront of a speaker. It won’t do a thing in the bottom two thirds of the spectrum. Works the same way over the insulation

[@gwsound]

This is exactly what I did to find out how to solve some standing wave issues. By the way what could I do with a 250hz buildup in my room? This is the only real issue that is still there. It starts around 160, peaks at 253 and then rolls of again almost symmetrical.

[@KingOath]

If you can’t get away from it by changing your positioning why not try helmholtz resonators. If it’s a predictable and consistent problem centred around a narrow band, it’s the only major issue and it’s not down too low it’s a perfect candidate.

[@KingOath]

Are your speakers close to some large object? That sort of frequency range is usually right where you get issues from furniture or other large items near the speakers. It could also be the physical resonance, not reflection, of a large item or the drywall etc, like the panels of a desk vibrating at 250hz. Try running a sine wave at that centre frequency nice and loud and go around the room to see if you can hear or feel anything resonating

[@ckdotdotdot]

It could also be worth considering the frequency response of your monitors and making sure there's not some sort of weird buildup related to those, I've definitely found that even after treating my space that my really cheap monitors had really poor consistency in the bass-upper bass region. You could maybe use a miniDSP interface or a system-wide EqualizerAPO to at least trim the response a little bit? I found EqualizerAPO particularly helpful since it's free and you can also get a feel for any potential monitor-related frequencies might be causing problems

[@gwsound]

@@KingOath This is exactly what I did. 250Hz at 80db. Then measure the signal. I feel the resonance in everything, like the dry wall, my headphone amp etc. Pretty amazing.

[@gwsound]

@@ckdotdotdot Could be, I have new monitors, ATC SCM50a pro.

[@manuellujan5625]

Alot of our main concerns is is Rockwool safe to have exposed in our studios? Can someone give us a detailed answer on why it is or why it is not?

[@NoQualmsTheArtist]

The fibres too small to see, are floating around your room and getting into your lungs just like asbestos. Please don't have exposed rockwool anywhere 🤨

[@manuellujan5625]

@@NoQualmsTheArtist what may you recommend to treat the room instead of Rockwool?

[@NoQualmsTheArtist]

@@manuellujan5625 you can use rockwool, just wear a proper graded mask when handling. And make sure you cover it with the right material when you make your panels. Just don't leave them exposed.

[@KrisTiasMusic]

@@manuellujan5625 Basotect by BASF is the industry standard.

[@m76353]

i've looked into this a lot. there seems to be two points of concern: 1) volatile organic compounds or "VOCs" for short, and 2) micro fibers. micro fibers are the ones i was worried about and altho there are no 100% clear answers, imo it comes down to 2 questions: (Q1) do rockwool and rigid fiberglass insulation emit micro fibers over time? probably at least to some degree, yes, especially with lots of bass. altho i'm not any kinda expert so look it up on your own too, but having read a lot about this, the people who say that "micro fibers are emitted" seem way more convincing and professional than the people saying there aren't. (Q2) does chronic exposure to micro fibers cause diseases like "pulmonary fibrosis", etc? yes, altho not in everyone. the solution to this would be to seal it air tight in thin plastic. some people even prefer this because cause it reflects some of the highs and high mids while still absorbing the bass giving a more even response. and then you can easily get rid of more highs and mids with blankets etc if needed. then there is also VOC "off gassing" too, which can cause certain health shit too from what i understand, altho there seems to be a couple more straight forward solutions to this, (1) they do make low-VOC rigid fiber boards like "safe n sound". i've heard you can also leave the higher VOC boards outside for the first 2 or 3 weeks after you unwrap them and most of the forameldyde and other chemical shit goes away. again tho, i'm not an expert, this is just shit i've read about in forums and different places. i'm personally going to use the low voc shit and the wrap that shit in plastic as well cause i'm paranoid as fuck about all this shit lol

[@DanielPaddington]

What do you think the flow resistivity of acoustic foam (eg Auralex and the likes) is?

[@DjD1MAH]

i read somewhere that shredded denim is a good material for acoustic insulation is this correct?

[@gyasirossmusic]

Hey I've checked out a few of your videos and really appriciate the advice you give! The only thing I'd like to mention is voodoo is a African Hatian religion so you might be alienating some folks with that starting line. Just putting it out there and nothing but respect and I enjoy that content.

[@orcalator]

I don't have a studio but i have an apartment where i constantly hear 50hz sound that is emitted by some device (probably AC) in some other apartment. Sound is the strongest in one corner of a living room and it's a bit annoying when watching TV. What would be the best to use to eliminate this sound? Thx.

[@user-cr4pz5yg7y]

Electrician. You have a ground loop

[@felixando7492]

such a good point

[@HKprod90]

what kind of plastic is used?

[@BoredSilly666]

Another great video Thanks

[@gthibert]

Hi Jesco! Isn't flow resistivity of Rockwool closer to 16 000 than 6 000?

[@okaight7248]

Safe n Sound is around 10k

[@ERMAV]

I just used corn cobs and newspaper.

[@codgerfiasco]

I don't really understand what you are saying. Are you saying that if the insulation was taken out of the plastic, then compressed so it is 2x as tightly packed, only then would it absorb bass?

[@manuprofesor]

Hi. What would happen if I use a painted picture (art canvas) and behind it is the soundproofing sheet? Soundproof material+wood frame+painted canvas over.

[@MuzdokOfficial]

it's about acoustic treatment not soundproofing 😎

[@sekritskworl-sekrit_studios]

I LOVE how many of these questions have already been answered for me. I really appreciate it. Question: What happens if airs gap is created between packages? Or if they are physically touching... however they are staggered in placement, introducing pockets of air in certain connection points?

[@RaytownProductions]

I think the answer is to experiment and take measurements to see what the impact actually is. Usually home studios are extremely difficult to predict what happens acoustically within them as they don't really follow standard models very closely (weird shapes, different materials, room within a room, etc). Hope that helps!

[@themattprofessor]

Does anybody have any idea what the flow resistivity of RWA45 rockwool 100mm and 50 MM panels. Also what happens to the absorption curve if you make a very deep 900mm trap?

[@Carguylogan]

In a situation where you know you aren't changing the room ever, what if you simply took a long piece of fabric and stapled it to each side of the corner from the floor up to nearly the roof, sealed it on the floor and dumped in blown insulation from the top? Seems like a super easy corner trap.

[@Sentientfx1]

Cool. I'm enjoying these videos. Have you considered covering a Dolby Atmos space? More studios are going over to it and it seems to me the phase implications could be, well, 'interesting'... :-)

[@Mikkelfrost]

tryed to get the pdf but the side says i cant ??? ned hælp

[@JulianFernandez]

thanks!

[@peterstampfl9094]

Hi could you make a video or answer the question, what to do with a needed heat radiator in the room?

[@analogalchemy]

Letting plastic flap with the pressure wave is just always bad, no. Don't be lazy. Maximize surface area, eliminate resonance.

[@christianraabe6669]

Würdest du auch Videos auf Deutsch machen ?

[@scottsmith4145]

Actually having plastic wrap on is the best way to use this nasty stuff imo. It keeps the nasty unhealthy particles inside so your not breathing them in your lungs while reflecting the mids and highs which overly deaden the room if absorbed. Then simply use foam to control higher freqs at the reflection points. Low energy is not as directional as mids and highs so you dont necessarily need a bass trap at the reflection point but if you chose you could put a trap there and layer foam over top. The corners are the obvious points for the bass traps.

[@pipelineaudio]

Its so counterintuitive, you figure if the air cant get stuck in it, it does nothing

[@mkexposed]

Doesn't anyone know that Rockwool is made using Formalydehide and is thought to cause cancer? I was about to buy a tonne of it until I found out. :(

[@michaelous]

Just keep it sealed in plastic, then it shouldn't be a problem

[@saber0089]

It is UL Greenguard Gold certified for indoor VOC emissions, so it should be safe. The formaldehyde amounts are at trace levels and should quickly dissipate throughout the house. However, it's possible they did not heat up the material long enough at factory so a rule of thumb is if you smell it then it's over safe levels. Formaldehyde is also in just about everything in trace amounts off gassing.

[@manuellujan5625]

@@saber0089 how would we be able to smell it? Do you know more or less what type of smell it may be? I want to be safe lol

[@ronsauro5413]

"full absorption"? 100% ... if so ...what sound is left to hear... simulations are only as good as actual testing measurements to back them up.

[@KomaRecords]

Mineral wool insulation needs to be 100% closed from the outside environment if not symptoms may include irritated, itchy, watery, or burning sensation of the eyes, nose, or throat, or itchy skin or skin rashes.

[@donpayne1040]

Yes. Buy these rolls! In semi covered plastic! Pump bass into them, and those fibres rubbing against each other! Yeah.

[@Zeropadd]

💜💙💚🤎

[@ronsauro5413]

Sorry... testing proves this does not work as indicated...

[@digidope]

No, You can't change "density" by compressing the material. That is not how it works. When compressing you simply close the fibers together and they stop to work. You do that when doing insulation it will not keep the cold out. It needs to be uncompressed to work. Acoustic performance is no different. There is even difference how the fibers are arranged. Please do a video where you test your theory by using REW. First in the bag and the out of the bag.

[@saber0089]

Compressing material is literally lowering the volume while maintaining the same mass, thus increasing its density. Increasing the density certainly changes the materials acoustic or thermal properties though. It likely would drastically decrease it's bass absorption as you say, but not make it stop working altogether. It would ender up costing more than just using rigid fiberboard instead.

[@dwaaaiii8757]

Can you elaborate more? How will compressing it not increase the density?

[@digidope]

@@dwaaaiii8757 Conpressing it will break the functionality of the wool. It is the same as when using it as insulation: It only insulates when it's loose, if you compress it, it will not insulate and will not keep your house warm . It says that very directly on the instructions. Acoustics use the same logic.

[@digidope]

@@saber0089 Nope. It works by vibrating the fibers. If you press the fibers together with force, it will not vibrate anymore. In dense wool there way more fibers to vibrate in smalle space, but you can't replicate that by compressing loose wool. It's still better than nothing.

[@Canadian_Eh_I]

@@digidope I have this same suspicion. In my minds eye I imagine sound just going 'around'' the packaged wool, like water around a rudder. Whereas the loose wool would adsorb the sound waves more effectively. Perhaps I am wrong though...we need a study!

[@Lishkabro]

Ya'll wanting to leave the insulation in it's plastic wrapping are kidding yourselves. Go do the work, enjoy the process, it's the journey, you'll look back at it, be at prime peace knowing you executed it well.. or to keep it simple stupid.. stop being lazy.