Acoustic hangers

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

Moderators: Aaronw, sharward

John Sayers
Site Admin
Posts: 5462
Joined: Mon Jan 27, 2003 12:46 pm
Location: Australia
Contact:

Re: Acoustic hangers

Post by John Sayers »

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

If this site helps you build your studio please use the Donate button.
Gregwor
Moderator
Posts: 1501
Joined: Wed Feb 01, 2017 6:03 pm
Location: St. Albert, Alberta, Canada

Re: Acoustic hangers

Post by Gregwor »

@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
It appears that you've made the mistake most people do. You started building without consulting this forum.
xSpace
Moderator
Posts: 3823
Joined: Sat Aug 25, 2007 10:54 am
Location: Exit 4, Alabama
Contact:

Re: Acoustic hangers

Post by xSpace »

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.
TomessAI
Posts: 24
Joined: Tue Aug 24, 2010 9:22 pm
Location: Düsseldorf, Germany

Re: Acoustic hangers

Post by TomessAI »

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?
John Sayers
Site Admin
Posts: 5462
Joined: Mon Jan 27, 2003 12:46 pm
Location: Australia
Contact:

Re: Acoustic hangers

Post by John Sayers »

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

If this site helps you build your studio please use the Donate button.
TomessAI
Posts: 24
Joined: Tue Aug 24, 2010 9:22 pm
Location: Düsseldorf, Germany

Re: Acoustic hangers

Post by TomessAI »

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
John Sayers
Site Admin
Posts: 5462
Joined: Mon Jan 27, 2003 12:46 pm
Location: Australia
Contact:

Re: Acoustic hangers

Post by John Sayers »

I meant you cover the opening where the hangers are.

cheers
john
John Sayers Productions

If this site helps you build your studio please use the Donate button.
Paulus87
Senior Member
Posts: 652
Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Acoustic hangers

Post by Paulus87 »

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
Paul
xSpace
Moderator
Posts: 3823
Joined: Sat Aug 25, 2007 10:54 am
Location: Exit 4, Alabama
Contact:

Re: Acoustic hangers

Post by xSpace »

Your glue should be like a 3m spray adhesive...it doesnt get messy ;l
Paulus87
Senior Member
Posts: 652
Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Acoustic hangers

Post by Paulus87 »

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
Paul
Hebster
Posts: 5
Joined: Thu May 19, 2011 3:53 am
Location: Helsinki, Finland

Re: Acoustic hangers

Post by Hebster »

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!
Paulus87
Senior Member
Posts: 652
Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Acoustic hangers

Post by Paulus87 »

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
Paul
Hebster
Posts: 5
Joined: Thu May 19, 2011 3:53 am
Location: Helsinki, Finland

Re: Acoustic hangers

Post by Hebster »

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!
Paulus87
Senior Member
Posts: 652
Joined: Sun Mar 02, 2014 8:42 am
Location: Wales, UK

Re: Acoustic hangers

Post by Paulus87 »

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
Paul
Skai_Penalva
Posts: 65
Joined: Thu Nov 01, 2007 8:44 pm
Location: Tegucigalpa, Honduras
Contact:

Re: Acoustic hangers

Post by Skai_Penalva »

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 (:
Sometimes the greatest risk is playing it safe
Post Reply