Whole wall acoustic treatment with fluffy insulation.

[neRok]

I'm going to do my whole front wall in "fluffy" insulation. I recently looked up some material options at my local hardware store (Bunnings), and here are those specs;

Edit: The only decent ones in stock today at my local are R3.5 ceiling batts, R2.0 wall batts, and R2.0 rolls. The wall batts and roll are equivalent and denser than the ceiling batt, so pretty much the ceiling batt seems the go presuming the specs are correct.

The R3.5 ceiling batts seem good (strange the R3.0 is denser, but whatever. maybe it's thickness vs performance?), and they are 430mm wide, and so I am willing to make the absorber that thick and just lay the batts flat on top of each other. But I imagine the weight of the stack will cause compression, so there will need to be supports every so often (every 2/3/4 layers)? This is what I am looking at now, and so wondering if anyone has any info or knows any good threads/resources regarding supporting the batts?

Perhaps stacking it a different way is better? Here's the ways that could happen;

Perhaps one of the "standing facing forwards" options is better because then 2*175mm thick batts = 350mm absorber, which seems a bit more reasonable? I wonder about them "falling out" though.

 

[ryanosaur]

It really seems like you are going to significantly over-treat your front wall. Generally speaking, you should only need to treat about 25% of the wall surfaces, total, and best success is had spreading that out with a combination of absorption and diffusion.

 

[sam_adams]

Perhaps stacking it a different way is better? Here's the ways that could happen;

 

[Justdafactsmaam]

I'm going to do my whole front wall in "fluffy" insulation. I recently looked up some material options at my local hardware store (Bunnings), and here are those specs;
View attachment 327035
Edit: The only decent ones in stock today at my local are R3.5 ceiling batts, R2.0 wall batts, and R2.0 rolls. The wall batts and roll are equivalent and denser than the ceiling batt, so pretty much the ceiling batt seems the go presuming the specs are correct.

The R3.5 ceiling batts seem good (strange the R3.0 is denser, but whatever. maybe it's thickness vs performance?), and they are 430mm wide, and so I am willing to make the absorber that thick and just lay the batts flat on top of each other. But I imagine the weight of the stack will cause compression, so there will need to be supports every so often (every 2/3/4 layers)? This is what I am looking at now, and so wondering if anyone has any info or knows any good threads/resources regarding supporting the batts?

Perhaps stacking it a different way is better? Here's the ways that could happen;
View attachment 327036
Perhaps one of the "standing facing forwards" options is better because then 2*175mm thick batts = 350mm absorber, which seems a bit more reasonable? I wonder about them "falling out" though.

What’s the goal? What speakers are you using? You can make absorption panels using rock wool. Wood framing, and some acoustically transparent cloth to cover it.

 

[neRok]

What’s the goal? What speakers are you using? You can make absorption panels using rock wool. Wood framing, and some acoustically transparent cloth to cover it.

Apparently light weight (fluffy) and deep is good at absorbing bass, and I'm sure it will clean up everything generally just like normal the panels you talk about.

It really seems like you are going to significantly over-treat your front wall. Generally speaking, you should only need to treat about 25% of the wall surfaces, total, and best success is had spreading that out with a combination of absorption and diffusion.

Apparently it goes good for bass.

View attachment 327043

There's a practical difference. The front facing ones can "peel away" from each other easily, falling in to the room. The "standing...side exposed" example doesn't have that problem, and has the benefit of fitting the room without trimming. All 3 standing options have the problem of "standing" though, so that's ~1.2m of unsupported lightweight material for the ones that are standing tall.

Anyway, I've bought the stuff, and going to start installing soon. I ended up with R4 ceiling batts. I'm not sure the "INSUL data" from my graphic is correct up to date because in store the R3.5 weighed 11kg and the R4.0 weight 11.4kg, and both are ~1.5m3, so it seems they are the very similar. I chose R4 because it is 195mm, so stack 12 for ~2.4m height, and 12 is easily divisible by 2 or 3 or 5 shelves (for 3 or 4 or 6 levels). I'm going to try 2 shelves = 3 levels, but as I'm typing this I realise that is ~800mm stack, which is pretty large. Maybe I should get a couple more brackets...?

An example of shelving it: https://gearspace.com/board/studio-building-acoustics/1392224-treating-my-small-room.html

 

[Andysu]

putting some fluffy in the corner of the THX cinema

 

[Rednaxela]

Thought fluffy was a foster parent pet.

 

[Justdafactsmaam]

Apparently light weight (fluffy) and deep is good at absorbing bass, and I'm sure it will clean up everything generally just like normal the panels you talk about.

View attachment 327082


Apparently it goes good for bass.


There's a practical difference. The front facing ones can "peel away" from each other easily, falling in to the room. The "standing...side exposed" example doesn't have that problem, and has the benefit of fitting the room without trimming. All 3 standing options have the problem of "standing" though, so that's ~1.2m of unsupported lightweight material for the ones that are standing tall.

Anyway, I've bought the stuff, and going to start installing soon. I ended up with R4 ceiling batts. I'm not sure the "INSUL data" from my graphic is correct up to date because in store the R3.5 weighed 11kg and the R4.0 weight 11.4kg, and both are ~1.5m3, so it seems they are the very similar. I chose R4 because it is 195mm, so stack 12 for ~2.4m height, and 12 is easily divisible by 2 or 3 or 5 shelves (for 3 or 4 or 6 levels). I'm going to try 2 shelves = 3 levels, but as I'm typing this I realise that is ~800mm stack, which is pretty large. Maybe I should get a couple more brackets...?

An example of shelving it: https://gearspace.com/board/studio-building-acoustics/1392224-treating-my-small-room.html

For bass it’s going have to be really deep. Several feet deep. If you are focused on bass I’d recommend diaphragmatic bass traps.

 

[Justdafactsmaam]

For bass it’s going have to be really deep. Several feet deep. If you are focused on bass I’d recommend diaphragmatic bass traps.

And measure the speaker/room with REW so you can target the standing waves

 

[Andysu]

Thought fluffy was a foster parent pet.

he's not fluffy he's Bear and yes very fluffy

 

[neRok]

Well, things have been done. 3 shelves (4 layers) seems good. That's 2 bags on the wall, and I've got a 3rd if need be (was thinking of doing a panel in on the odd shaped rear wall I have).


I've done a quick sweep and there is improvements but also a bit of a hole around 80Hz which isn't nice, but I'm too exhausted to get in to it further today.

 

[RayDunzl]

I knew a drummer who did the 4 walls, door and ceiling of a small bedroom using rolls of pink fiberglass, fluffy side out.

It seemed very effective.

Even the kick drums were barely audible from the adjoining rooms. You could hear when he was playing (or not) but it wasn't intrusive.

During that time at work we were quantifying photons and not electrons or phonons, so there wasn't anything pertinent to borrow from the lab with which to measure.

 

[A Cute Earring]

I wonder how safe it is to breathe the air in a room with all this material that is intended to be encapsulated.

 

[Andysu]

I wonder how safe it is to breathe the air in a room with all this material that is intended to be encapsulated.

i don't think as bad as may think or does it depend how much of it is spread around a room ? i stuffed fluffy rock wool in a sort of corner , at first upon opening the sealed bag , it has dry musty like smell ? after few , no days now with window open to air out the room , it seems somewhat less now ?

 

[neRok]

I wonder how safe it is to breathe the air in a room with all this material that is intended to be encapsulated.

The website says "Earthwool® is certified by Eurofins as an outstanding material according to the VOC (Volatile Organic Compounds) Indoor Air Quality emissions regulations."

I think I'll eventually cover the whole wall in cloth material, so it looks nicer. The wall is 3m long x 2.4 high = 7.2m2. Compare that to a normal sized DIY acoustic panel of 1.2m x 0.6m = 0.72m2, that means my wall is the same surface area as 10 panels, which is not an unusual amount, and thus the "risk" is about the same.

Also I didn't notice any discomfort from the wall yesterday. Actually there is a tiny bit of smell in the room but it is coming from the timber I used, which was treated fence palings. I used them because they seemed the cheapest option but must have been new because they were still a little "wet" (I looked up the timbers treatment details and it was deemed safe too). The fence palings are "ugly" and not particularly straight, but if they are getting covered in material then what's the difference?! 150x17mm x 1.8m paling was ~$7.5, vs dress pine 140x19mm x 1.8m = ~$17.5, or 140x12mm x 1.8m ~$20.

 

[neRok]

Below is a couple of pics from yesterdays effort.

Here's one of the wall with my speakers in position;

I noticed that the strip of "vertical" I put in (orange box) helps hold up the horizontal batts (red box), which was handy. Also the rough timber palings somewhat grip and hold up the top batts (green line).

I made 2 panels that will hopefully help the "double back wall" problem I have. I need to put another bracket in at mid height to hold them both against the wall today, but otherwise they are free standing to keep it simple.

The palings are 150mm and the batts 195mm, but they seem to pack in fine. Also the panels are ~1.1m tall and ~0.6m wide (dictated by available offcut lengths), so the 430mm batts dont fit length wise (would need ~1.5 batts), so instead I used 3x rows of batts and squished them vertically too. It probably doesn't do a lot at the ~160Hz problem being not so thick and now compressed to boot, but whatever, it's better than an unmitigated reflection.

I also think my PC desk was noisy, because the "back board" maybe vibrated a bit like a drum when the sub got loud. So I used a paling as a brace and also stuffed it;


I spent a bit of time last night working on the EQ/XO, which was coming along nicely. I was doing so with the speakers quite forward, but then I shifted them back to get more of an equilateral triangle going, and it sounds much better. I'll start another thread to discuss the sound quality so that this one stays on topic with my OP question regarding the "structural" aspects of this endeavour.

Edit: I still have to investigate the 80Hz null I have. I am now sitting ~400mm further back in the room than I was before, so maybe I'm sitting right on the null, or maybe the sub/speakers are right on the null? It seems the modes still work as modes (the sound still reflects off the walls the same), they just drop off quicker.

 

[Justdafactsmaam]

Below is a couple of pics from yesterdays effort.

Here's one of the wall with my speakers in position;
View attachment 327942
I noticed that the strip of "vertical" I put in (orange box) helps hold up the horizontal batts (red box), which was handy. Also the rough timber palings somewhat grip and hold up the top batts (green line).

I made 2 panels that will hopefully help the "double back wall" problem I have. I need to put another bracket in at mid height to hold them both against the wall today, but otherwise they are free standing to keep it simple.
View attachment 327941
The palings are 150mm and the batts 195mm, but they seem to pack in fine. Also the panels are ~1.1m tall and ~0.6m wide (dictated by available offcut lengths), so the 430mm batts dont fit length wise (would need ~1.5 batts), so instead I used 3x rows of batts and squished them vertically too. It probably doesn't do a lot at the ~160Hz problem being not so thick and now compressed to boot, but whatever, it's better than an unmitigated reflection.

I also think my PC desk was noisy, because the "back board" maybe vibrated a bit like a drum when the sub got loud. So I used a paling as a brace and also stuffed it;
View attachment 327943

I spent a bit of time last night working on the EQ/XO, which was coming along nicely. I was doing so with the speakers quite forward, but then I shifted them back to get more of an equilateral triangle going, and it sounds much better. I'll start another thread to discuss the sound quality so that this one stays on topic with my OP question regarding the "structural" aspects of this endeavour.

Edit: I still have to investigate the 80Hz null I have. I am now sitting ~400mm further back in the room than I was before, so maybe I'm sitting right on the null, or maybe the sub/speakers are right on the null? It seems the modes still work as modes (the sound still reflects off the walls the same), they just drop off quicker.

I would be curious to see the impact on REW

 

[Andysu]

before after place mic where fluffy will likely be placed , do multiple REW sweeps of the area , after fluffy has been placed place mic behind fluffy , stuff the mic into fluffy where some gloves as fluffy can be itchy on the skin , then take REW sweep and compare the multiple of frequency sweep overlays

 

[Flaesh]

I would be curious to see the impact on REW

Yep!

 

[DVDdoug]

I've done a quick sweep and there is improvements but also a bit of a hole around 80Hz which isn't nice,

That's the kind of thing that real bass traps should help with. Kill (or reduce) the reflected waves and you kill (or reduce) the standing wave nulls/cancelations (and the anti-nodes/bumps).

...You can fix the bumps with EQ but it takes "infinitely large" subwoofers and "infinitely large" amplifiers to overcome cancelation.