Acoustic hangers

[almaelectronix]

It's not the only one I can get, they also sell 3, 4, 5mm, etc and I can choose between chipboard, osb, mdf.

I think the chipboard is less dense.
Maybe 3mm will be better as a core because it's more flexible and will have less mass per m2. What do you think?

Also is it better to design the width of the panels in a way that they interfere with my measured frequency responce?
i.e. the fλ/4 and 3fλ/4 falls right on peak frequencies, and fλ/2 on dips?
Of course keeping a variation on sizes.

[Soundman2020]

Also is it better to design the width of the panels in a way that they interfere with my measured frequency responce?
i.e. the fλ/4 and 3fλ/4 falls right on peak frequencies, and fλ/2 on dips?

Not really necessary. I just try to make them as large as I can fit in. As the saying goes "size matters"...


- Stuart -

[almaelectronix]

Good news, searching for the right chipboard as an alternative, i did found the actual think I need!

It's homasote indeed!

The company selling it renamed it to "insulite", here in Greece, that's why i couldn't find it!

They are out of stock for the 12.5mm, but they got plenty of 10mm sheets, so I will go with that!

[Soundman2020]

Perfect! Glad you found it.

- Stuart -

[SGleason]

It's homasote indeed!

I just read this whole most excellent thread and with all of the chatter about Homasote I thought I should clear up a few misconceptions for folks who might be just reading. You see, while I am not here at the forum as such, I am the Technical Director at Homasote Company.

Homasote is a very unique substrate that is unlike any fiber board anywhere. The recipe for Homasote was brought over to the US from the UK in 1909 and it is proprietary. It is made from compressed recycled paper rather than from wood fibers with an adhesive binder. It has no adhesive and is held together, instead, by the surface tension between the mechanically interlocked fibers. There is even some good old hydrogen bonding going on as well. Because of this the substrate is much stronger that those typical wood fifer based fiber boards.

John is right about the fact that it is a great tack board, but it's real use these days in in floor/ceiling and wall assemblies as a sound control component. For purposes of this discussion here are some pertinent data points:

if you are going to use Homasote is this fashion you don't want PINnacle. PINnacle is a decoratively sanded version of the basic Homasote substrate that is used as a tack board. You want the basic board that is called 440 SoundBarrier. Unfortunately, it won't be readily available outside of the US (except in Canada).

Density: 440 Kg/m3 (nominal). That's just under the official range for MDF.

NRC: 0.10 ASTM C-423 (Reverberation Room) SA is 0.55 @ 125Hz but it drops off precipitously after that.
0.20 ASTM C-384 (Impedance Tube)

This may be the only time I speak about the product here on the forum as that is not why I am here. When I step away from the Homasote Tech Desk I am just a self recording songwriter who is always trying to get my room sounding better....just like lots of you who may be reading this.

Steve

[Paulus87]

It's homasote indeed!

I just read this whole most excellent thread and with all of the chatter about Homasote I thought I should clear up a few misconceptions for folks who might be just reading. You see, while I am not here at the forum as such, I am the Technical Director at Homasote Company.

Homasote is a very unique substrate that is unlike any fiber board anywhere. The recipe for Homasote was brought over to the US from the UK in 1909 and it is proprietary. It is made from compressed recycled paper rather than from wood fibers with an adhesive binder. It has no adhesive and is held together, instead, by the surface tension between the mechanically interlocked fibers. There is even some good old hydrogen bonding going on as well. Because of this the substrate is much stronger that those typical wood fifer based fiber boards.

John is right about the fact that it is a great tack board, but it's real use these days in in floor/ceiling and wall assemblies as a sound control component. For purposes of this discussion here are some pertinent data points:

if you are going to use Homasote is this fashion you don't want PINnacle. PINnacle is a decoratively sanded version of the basic Homasote substrate that is used as a tack board. You want the basic board that is called 440 SoundBarrier. Unfortunately, it won't be readily available outside of the US (except in Canada).

Density: 440 Kg/m3 (nominal). That's just under the official range for MDF.

NRC: 0.10 ASTM C-423 (Reverberation Room) SA is 0.55 @ 125Hz but it drops off precipitously after that.
0.20 ASTM C-384 (Impedance Tube)

This may be the only time I speak about the product here on the forum as that is not why I am here. When I step away from the Homasote Tech Desk I am just a self recording songwriter who is always trying to get my room sounding better....just like lots of you who may be reading this.

Steve

Thanks for the info and data, nice of you to share it with us. However, I think it sucks that it’s not available outside of the US and Canada - at least make it available in the UK (where I’m from) seems only right considering that’s where it’s from originally!

Paul

[SGleason]

Hey Paul....

There is actually a company in the UK that may be the great grandfather of Homasote. Their products appear to be a bit watered down now...all kinds of poofy colored tackboards...but they are made the same way as Homasote.

https://www.sundeala.co.uk/

Steve

[Soundman2020]

I think it sucks that it’s not available outside of the US and Canada

I have to agree with that!

at least make it available in the UK

... and maybe Latin America, too! Or at least Chile....

We can get cork, thick cardboard, and other types of fiber board, but they aren't the same....

- Stuart -

[SGleason]

I wish it was that easy. Unfortunately, Homasote Company doesn't sell directly into the market. The product goes through distribution to local dealers. Product does get shipped overseas from the US all the time for large projects in the Mid-East, Korea, Japan...lots of places. They buy it for specific projects that require sound control or tackable acoustic panels.

We can get cork, thick cardboard, and other types of fiber board, but they aren't the same....

I'm glad that John likes Homasote for these hangers but I'm thinking that the unique attributes of Homasote are not really that big a deal in this application. That .55 SA at 125 Hz may be helping things but other than that I think any substrate that is lighter than plywood or OSB might perform as well. In fact, any of the wood based fiber boards would likely perform as well in this application as they have similar or slightly higher absorption coefficients.

Products like:

https://www.blueridgefiberboard.com/sou ... deadening/
or
https://bpcan.com/produits/soundproofing-panels/

I would never recommend these products for sound attenuation assemblies as they can't hold a screw like Homasote.......with Homasote you can decouple the GWB. But these substrates are softer than Homasote so they have higher absorption numbers. They would probably be beefy enough to handle this job and there are lots of other similar products all over the world (I think). I'll spend some time today researching that.

I wonder if Micore (USG) might work. Micore 300 is a true mineral fiberboard that is also a bit softer than Homasote and has a slightly higher NRC.

https://www.usg.com/content/usgcom/en/p ... board.html

Steve

[almaelectronix]

I am describing on this post the homasote alternative that I've found.

[Paulopost]

I also prefer Zachtboard. Just like I prefer EnduraSeal 100% Acrylic Semi-Gloss Concrete Sealer I found at https://bestdrivewaysealers.org/best-co ... d-reviews/ for my patio. A very artistic approach for me I would say.

[Paulus87]

I actually think we can get better results if we construct hangers with a much denser core, such as 12-18mm plywood/MDF.

Philip Newell even builds them from varying thicknesses of ply.

Although the Homasote is nice because it is light weight (especially in a ceiling) I actually think this makes them less effective as wave guides overall, a simple visualisation: if we wanted to attempt to redirect waves in the ocean then what would have a better chance at doing so? Mushy compressed fibres or dense rigid panels?

My theory is the rigid panels will resonate at certain frequencies depending on their mass, which means there is some energy transfer and less energy comes out than went in at those frequencies, and the insulation dampens this resonance. At the same time it will break up the waves which are not absorbed fully, causing an impedance mismatch which will dissipate the energy (reflecting it like a ping pong in the maze of hangers) and absorb it further in the air in between and insulation behind/below/above/in front of the hangers.

I do not believe the hangers even need to be hung for this to work, and might even work better if the angled wave guides were fixed in place, almost constructed like a big unsealed 1d diffuser with "fins" and insulation between them. Though, the flex element of the freely swinging hangers may be an important factor.

Either way, I do not believe it is Homasote that is creating the magic here.

[Gregwor]

Either way, I do not believe it is Homasote that is creating the magic here.

The absorption coefficients of Homasote will help a lot too though.

Greg

[Paulus87]

Either way, I do not believe it is Homasote that is creating the magic here.

The absorption coefficients of Homasote will help a lot too though.

Greg

Maybe, what is the absorption coefficient of Homasote by the way?

Paul

[Gregwor]

Here is one Homasote lab test result:

Homasote C423.pdf

It's not amazing, but it's certainly not bad!

Greg