Err, he said there is almost no difference. Or did I just watch another video?

@@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.

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

^^^^^ this. Very important considerations.

Any room for you and speakers?😀

​@@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.

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

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

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.

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

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.

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!

Safe n Sound is around 10k

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.

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

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

@@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.

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

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.

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

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.

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

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

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.

@levibalint3253 If need data I can look for my measurements

@@DmitryMyadzelets i’d be curious

@@levibalint3253 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.

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 🤨

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

@@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.

@@manuellujan5625 Basotect by BASF is the industry standard.

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

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

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.

@@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

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.

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

@@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.

@@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.

@@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!