Acoustic hangers

TomessAI wrote:

Hello! 440 Soundbarrier: 440 kg/m³ Claytec HFA maxi: 250 kg/m³

Seems like if you double that, like use 2 pieces, you increase the absorption ability. I know that this doubling can be frowned upon but it isn't mass we are talking about. It is dense insulation right?

xSpace wrote:

TomessAI wrote:

Hello! 440 Soundbarrier: 440 kg/m³ Claytec HFA maxi: 250 kg/m³

Seems like if you double that, like use 2 pieces, you increase the absorption ability. I know that this doubling can be frowned upon but it isn't mass we are talking about. It is dense insulation right?

Thank you for your reply! :D The Claytec HFA maxi board is 2 cm thick (a bit thicker than 5/8"). So, if the normal used 440 Soundbarrier for hangers is 1/2" (approximately 1,3cm) it is nearly twice as thick. So, it should be nearly the same form the weight perspective. But I got another question: how to glue the glaswool onto the wood fiber board? Should I use spray glue like this one? It is available where I buy the most of my materials.

But I got another question: how to glue the glaswool onto the wood fiber board?

Screws and fender washers :thu: Greg

I would suggest spray adhesive. Anything that compresses the insulation reduces the ability of the the product to do the job it is intended to do. A spray glued attachment leaves the product free to do 100 percent of the job it was designed to do. If you screw it in with washers, while it may still be effective, it has been reduced in effectiveness .

Gregwor wrote:

But I got another question: how to glue the glaswool onto the wood fiber board?

Screws and fender washers :thu: Greg

xSpace wrote:

I would suggest spray adhesive. Anything that compresses the insulation reduces the ability of the the product to do the job it is intended to do. A spray glued attachment leaves the product free to do 100 percent of the job it was designed to do. If you screw it in with washers, while it may still be effective, it has been reduced in effectiveness .

Uh-oh, two Mods and two opinions :mrgreen: @Gregwor, I've seen those fender washers, do you mean those? I would need ca. 300-400 pieces max. if I use 4 per piece of glasswool sheet. I've calculated it. If I use 4 pieces with screws on both sides i would add 120g of extra mass in total. The mass of the wooden fiber borad is 6,25 kg/m² with 2cm thickness. Most of the pieces of my hagers are 0,9 m² (1,5m x 0,6m), which would be 5,6 kg per piece. So, I would add 2,14 % of mass to them. For the smaller pannels, it would be more of course. Is this negligible? @xSpace, I would need 15 x 500ml cans, if the datasheet is trustworthy and one can can be used for approximatley 4 m² per can. This would cost me nearly 4 times as much. I would feel more secure if I would use Glue, since it will add nearly no new mass. Otherwise is 440 Soundbarrier slighetly heavier... What would you guys say?

I'd use glue along the top of the fibreglass so it hangs freely. cheers john

@Gregwor, I've seen those fender washers, do you mean those?

Those would work fine for what I described. As John said, a strip of glue along the top with a couple of those fender washers (NOT compressing the insulation) would hold it well. Greg

Glue is what I would use as a means to attache the insulation to the panels. But, screws and fender washers will work, just purchase a long enough screw so as not to compress the insulation. As you may already be aware, there is no known data on how these hangers actually produce the effect they achieve. So anything that goes in the other direction of how they were originally built may have a negative effect.

Thank you very much, Gregwor, xSpace and John, I will do like you said, use glue on top and let the glasswool sheets hang. One last question regarding this topic: Since I will use sackcloth as false walls in front of the hangers I'm worried about the glaswool fibers. They could easily flow through the cloth. As I've read in this thread, I want to pack the hangers in thin plastic sheets. The sheets I want to use are 10µm thick. Would this compromise the hanger effect? Or is there another way to prevent the fibers from the glasswool from flowing around?

I'd add a layer of plastic over the hanger area opening before you add the sack cloth. cheers john

Hey John, thank you very much for your reply, but this only applies to the area behind the hanger area and not the hangers itself, am I right? Or did I missunderstood? I was planning to cover the walls of the framewoork where the rockwool is located like you've showed in the picture. Thomas

I meant you cover the opening where the hangers are. cheers john

For my hangers I used very fluffy low gfr insulation @150mm thick. I attempted to glue it on to the homasote at first but it was a disaster... I can imagine it being okay with semi rigid thinner insulation slabs but I found that the glue could not adhere properly to the insulation and it just fell off. I ended up using a load of cheap washers and screws just along the top of the hangers in the end and it was super quick and easy with no mess. I would also be wary of covering large sections of wall or ceiling in plastic as this could end up trapping moisture and rotting out your timbers/drywall. Maybe it depends on the climate but it could end up being a very heartbreaking error. Paul

Your glue should be like a 3m spray adhesive...it doesnt get messy ;l

xSpace wrote:

Your glue should be like a 3m spray adhesive...it doesnt get messy ;l

Yep, tried it, didn't work. As I said, for semi rigid insulation I'm sure it's fine, but for the very fluffy loft roll @ 150mm thickness it really doesn't hold. The mess is salvaging half torn batts up off the floor which have fallen off homasote board, and then starting all over again :D Paul

I'm planning to build hangers to my next temp-place and have few questions. My roof will be right-tringle so that left side height is about 220cm and left side is 320cm. I'm planning a dropped ceiling to 220cm height with basic acoustic tiles. There will be plenty of space above the dropped ceiling and i was thinking to fill it with hangers. Room length is 470cm so it would have room for many hangers. Width is 375cm. 1. How many hangers is good amount in that space? 2. All same size to as big as possible or mix smaller ones in? 3. Fiberboard or MDF? Some designers say it should be MDF so those would act as waveguides, others say it should be fiberboard. My walls will be fiberboard so i will have that plenty anyways. MDF is quite heavy so can't probably put as many as i could put fiberboard ones. I know this is just temp solution. Later at somepoint the shed will be re-built from ground up. I would like to do as much re-usable treatment as possible. The ceiling will stay about same size, so i could re-use all hangers in the next build. Space is half of yard shed and the walls will be quite thin. Idea is to let as much sound out as possible to annoy neighbours :yahoo: Thanks!

Use mdf if you’re going to hang them at an angle - the fibreboard will bow unless supported with some barren supports on each hanger, and will require more fixings so they do not bow. Mdf is higher density, more reflective to low frequency and would be more effective in my opinion. I used fiberboard due to weight but would have chosen ply or particle board if I could have. Fit them evenly, aiming towards the speakers if you can. If they overlap a little then it’s ideal as long as they do not touch. Paul

Paulus87 wrote:

Use mdf if you’re going to hang them at an angle - the fibreboard will bow unless supported with some barren supports on each hanger, and will require more fixings so they do not bow. Mdf is higher density, more reflective to low frequency and would be more effective in my opinion. I used fiberboard due to weight but would have chosen ply or particle board if I could have. Fit them evenly, aiming towards the speakers if you can. If they overlap a little then it’s ideal as long as they do not touch. Paul

Good ideas. I was not thinking to angle the hangers. Just hanging those vertically is easy, but if there is benefit to angle those then i will look into that. Why angle hangers towards speakers? If there is noticable difference in angling, then i would do at least some with plywood or mdf and rest with fiberboard. Fiberbboard is low cost solution, but like you said it can't be angled without additional support. If i put say 20 hangers to the ceiling, do i still need the acoustic tile ceiling under them? The acoustic tile system is quite expensive here, so if i could skip that it would be great. I do have 240x120x10cm cloud from my last room that i could use in the next one. Also, would it make a difference if i would glue 20-50mm 703 to the celing? It might dampen the ceiling a bit more, but it's additional cost. The fluffy stuff can be found cheap from online market places, but 703 is harder to find. Thanks!

Hebster wrote:

Paulus87 wrote:

Use mdf if you’re going to hang them at an angle - the fibreboard will bow unless supported with some barren supports on each hanger, and will require more fixings so they do not bow. Mdf is higher density, more reflective to low frequency and would be more effective in my opinion. I used fiberboard due to weight but would have chosen ply or particle board if I could have. Fit them evenly, aiming towards the speakers if you can. If they overlap a little then it’s ideal as long as they do not touch. Paul

Good ideas. I was not thinking to angle the hangers. Just hanging those vertically is easy, but if there is benefit to angle those then i will look into that. Why angle hangers towards speakers? If there is noticable difference in angling, then i would do at least some with plywood or mdf and rest with fiberboard. Fiberbboard is low cost solution, but like you said it can't be angled without additional support. If i put say 20 hangers to the ceiling, do i still need the acoustic tile ceiling under them? The acoustic tile system is quite expensive here, so if i could skip that it would be great. I do have 240x120x10cm cloud from my last room that i could use in the next one. Also, would it make a difference if i would glue 20-50mm 703 to the celing? It might dampen the ceiling a bit more, but it's additional cost. The fluffy stuff can be found cheap from online market places, but 703 is harder to find. Thanks!

They will work whether angled or not but Philip Newell and Tom Hidley (pioneer of the hangers) angle them towards the speakers on the ceiling, so the ones closest to the speakers are almost vertical gradually becoming more horizontal as you get further to the rear of the room. They are also angled at 45 degrees towards the speakers on the rear wall. The reason for this is because they act as wave guides, so the channels created between the hangers guide the waves to the boundary behind, which also is covered in some velocity absorption or membrane absorbers. Then, as the reflected wave tries to go back out it gets reflected and absorbed again off of the hangers again, ricocheting back and fourth between hangers until the energy is completely dissipated. The way I am hanging mine is installing eyelet hooks on the ceiling framing and the hangers themselves and then using small carabiners to attach. This way I can easily remove them if I ever need to. You could use chain, cable ties, wire, rope. Instead of a drop ceiling you could just make some timber frames and cover with stretch fabric with another thin layer of absorption behind. Btw, no need for oc705 just use cheap loft insulation. Paul

Hi everyone! I'm having trouble finding specific information addressing the angles that hangers should have in a back wall. I've seen some posts mention this but can't seem to find the science behind how the angles of the hangers work. Could anyone please point me in the right direction? Also, I've seen designs in other posts where the hangers are on the inside wall of the room covered with a breathable fabric, and others that seem to have the hangers inside the air gap between the 2 back walls. Is this correct? Can I place hangers inside the air gap between 2 leafs to achieve proper bass absorption? I appreciate any information to better understand how hangers work (:

Skai_Penalva wrote:

Hi everyone! I'm having trouble finding specific information addressing the angles that hangers should have in a back wall. I've seen some posts mention this but can't seem to find the science behind how the angles of the hangers work. Could anyone please point me in the right direction? Also, I've seen designs in other posts where the hangers are on the inside wall of the room covered with a breathable fabric, and others that seem to have the hangers inside the air gap between the 2 back walls. Is this correct? Can I place hangers inside the air gap between 2 leafs to achieve proper bass absorption? I appreciate any information to better understand how hangers work (:

I have a couple of academic papers on hangers which contain a lot of info and data, as well as how to construct them properly. Please PM your e-mail and I will send it to you. The way that Philip Newell does it is like so: 45 degrees for the rear wall, 10-20 degrees for the side walls, the ceiling hangers should be aimed at the loudspeakers so that only the hangers' leading edges are seen from the point of view of the loudspeakers. I do not know how well they work in the air gap, but seems like a waste to me. The inner walls would need to be quite lossy in order for that to be useful. They also take up a lot of space... the newell hangers are typically 1.2m wide and 3 or 4m tall (depending on room height). That is a seriously big air gap, in which case the cavity resonance will already be rather low anyway... you'd basically be creating very large membrane traps, and the use of hangers inside them might not be necessary. But, who knows? Paul

Hi Paul, Thank you so much for your reply! I would really appreciate the info you have on hangers. I'll PM you with my email. That's very kind of you "The way that Philip Newell does it is like so: 45 degrees for the rear wall, 10-20 degrees for the side walls, the ceiling hangers should be aimed at the loudspeakers so that only the hangers' leading edges are seen from the point of view of the loudspeakers." - Would you happen to have any pictures showing this? It's a little hard for me to understand in which direction they are angled or aimed. I can't tell which is the leading edge... I noticed on your studio build post you have hangers on your back wall. Did you cover these with fabric? Are they on the inside of the room? I thought they were inside the air gap. Also on the ceiling I noticed you did something similar. How are did you cover the ceiling? I wonder because I see pictures like the following one, and then studios with angled ceilings and back walls but they seem solid, not fabric.

I've sent you all the info you need in an e-mail. Paul

I just got it. Thank you so much!

Hello, I’m thinking about switching my back wall from 24” of 6000 GFR to hangers. I have a bunch of Armstrong ceiling tiles that are essentially 1” 703 or 705 with some sort of decorative binder on the front and notched edges. Could I glue this to homasote 440 to make effective hangers, or should I use thicker less dense insulation like Roxul 60 (I have some of this too). Thanks!