Sound Absorption?

[Dan F]

We're now mid-way through our the build and have applied 2 x soundbloc and a fair amount of resilient bars quite liberally throughout the house to get a decent level of sound insulation between rooms.  We also, with some advice from @Moonshine, followed a robust detail for intermediate floors which has been very effective.

 

Sound insulation is great, but we now have a lot of echo chambers throughout the house and given we don't plan to use any carpet anywhere, I am thinking that we may need to mitigate this somewhat.

 

I'm less concerned about bedrooms because once you have a bed, mattress and some curtains I don't think these will be a major issue, but on the ground floor where we have larger open plan areas without curtains I'm more concerned.   What brought this to my attention was when I started looking at speakers for some of the rooms downstairs and realised that it's pointless spending any decent money on speakers if the acoustics of the room are terrible. 

 

In the room where we plan to have a surround sound system I'm sure we'll probably want to put some kind of specialiast acoustic treatment, but in the other entertaining spaces is there anything that anyone would recommend?  We plan to use "Akupanel" in a couple of places,  although I've realised that for this to be effective you really need to put it on battons/insulation, rather than surface-mounted on top of plasterboard.   We can't use this everywhere though, so wondering if there is a simple alternative to standard PB/skim that we could use for ceilings that don't break the bank?

 

Come across these products, but no idea how avaialable they are or what they cost:

- https://www.quietstone.co.uk/product/quietspray/

- https://www.stil-acoustics.co.uk/Seamless-Acoustic/Acoplaster.html

- https://fadeceilings.com/product/plus/

 

 

 

Edited April 13, 2021 by Dan F

[gc100]

Hate to put a downer on what you have done but I put res bars and double layered acoustic plasterboard in my office/music room. Total waist of time - why ? Because of the stupid a*rs 10mm gap you have to under the door for building ventilation regs. I will be installing drop seals once signed off mind....

[Dan F]

7 minutes ago, gc100 said:

Hate to put a downer on what you have done but I put res bars and double layered acoustic plasterboard in my office/music room. Total waist of time - why ? Because of the stupid a*rs 10mm gap you have to under the door for building ventilation regs. I will be installing drop seals once signed off mind....

 

Master bedroom will have drop seal, so will TV room.    In master bedroom the MVHR extract in en-suite is the same as MVHR supply in bedroom so not needed here.  In the TV room we will be fitting a "acoustic air transfer unit", still need to source one though...

[gc100]

23 hours ago, Dan F said:

 

 In master bedroom the MVHR extract in en-suite is the same as MVHR supply in bedroom so not needed here.

 

Thats the same as mind. Building control wanted the gap none the less...

[Dan F]

9 minutes ago, gc100 said:

 

Thats the same as mind. Building control wanted the gap none the less...

 

Did they actually check and measure it on-site?  Did they know you were using MVHR and see the flow calcs... 

[Dan F]

Few more leads:

- https://www.baswaacoustic.co.uk/baswaphonclassicfine

- https://www.acosorb.com/acoustic-plaster

- https://www.oscar-acoustics.co.uk/acoustic-solutions/oscar-elite.asp

 

Almost certainly all a lot more expensive that standard board and skim, but I'll try to call a few and get some ballpark prices..

[tanneja]

On 13/04/2021 at 22:04, Dan F said:

 

Master bedroom will have drop seal, so will TV room.    In master bedroom the MVHR extract in en-suite is the same as MVHR supply in bedroom so not needed here.  In the TV room we will be fitting a "acoustic air transfer unit", still need to source one though...

I was considering adding an MVHR extract in the TV room (it already has a supply) so that it could have the sealed door.  Acoustic air transfer units seem effective from a youtube video I saw, but all DIY projects rather than a bought product.

[Dan F]

6 hours ago, tanneja said:

I was considering adding an MVHR extract in the TV room (it already has a supply) so that it could have the sealed door.  Acoustic air transfer units seem effective from a youtube video I saw, but all DIY projects rather than a bought product.

 

These are the links our MVHR guy sent us:

 

https://www.holyoake.com/product-details/LDO-T_item.html
https://www.koolair.com/en/catalogue/unidades-de-transferencia-de-aire-acustica-kat/#guia_seleccion
https://www.specifiedby.com/waterloo-air-products-plc/dsr-acoustic-air-transfer-grilles

[tanneja]

@Dan F no prices ? M TV room is right  next to the MVHR closet, I hope I have left over ducting and my eventual choice of distribution box has a spare port, as I can't imagine these ATUs will be cheap.  They don't seem to have lots of maze inside them, I expected more.  Our room is also a masonry wall, making retrofit a bit more of a job.  Thank you for the links

 

[SimonD]

Before going out and buying a load of panels, plus everything else you need, I'd highly recommend you get yourself a spectrum analyser. There are apps you can download onto your phone. You also need to work out the room's frequency response. This way you'll have any idea of the frequencies you need to target within the room to get the best results and know whether the room is likely to amplify certain frequencies. You can also measure ambient background noise produced by mvhr, pumps, washing machoines etc. so their noise gets dealt with too.  Looking at the acoustic panels, they provide very good noise absorption around about 1k Hz and above, but because they're thin their effectiveness will be reduced for lower frequencies (the sharp edges help a bit for refraction) as you'll see by the graphs produced by the manufacturer. TBH it is a bit pointless to spend loads on targeting higher frequencies only to be left with annoying low freguency hums, or the bass of a male voice.

 

You can get free software to help calculate the room modes, like Modecalc, which also has a tutorial.

 

Otherwise, there are products like Celenit and Savolit wood wool boards that have acoustic certification. Celenit has a calculation service to help with room design.

 

Here's also a link to a document that shows some common absorption coefficients of materials so you can compare to the products you're looking at. Noise control in Rooms

 

HTH.

 

 

Edited April 23, 2021 by SimonD

[Moonshine]

1 hour ago, SimonD said:

You can get free software to help calculate the room modes, like Modecalc, which also has a tutorial.

 

Caution if using this software as it only calcs axial modes,  not tangential and oblique modes, which can cause issues as well though are not as strong as axial modes as get absorbed / diffused by room surfaces.

 

Below is the room mode calc based on the modecalc example for all mode types (all = 0, axial = 1, tangential =2, oblique = 3), and there is a couple of tangential modes combining at around 75 Hz (75.3 and 75.5 Hz).

 

 

In regard to modes you want to get a nice even modal density so that the frequency response of the room is as flat as possible and any spikes are smooths via absorption or diffusion.

 

[Gus Potter]

On 13/04/2021 at 19:16, Dan F said:

We're now mid-way through our the build and have applied 2 x soundbloc and a fair amount of resilient bars quite liberally throughout the house to get a decent level of sound insulation between rooms.  We also, with some advice from @Moonshine, followed a robust detail for intermediate floors which has been very effective.

 

Sound insulation is great, but we now have a lot of echo chambers throughout the house and given we don't plan to use any carpet anywhere, I am thinking that we may need to mitigate this somewhat.

 

I'm less concerned about bedrooms because once you have a bed, mattress and some curtains I don't think these will be a major issue, but on the ground floor where we have larger open plan areas without curtains I'm more concerned.   What brought this to my attention was when I started looking at speakers for some of the rooms downstairs and realised that it's pointless spending any decent money on speakers if the acoustics of the room are terrible. 

 

In the room where we plan to have a surround sound system I'm sure we'll probably want to put some kind of specialiast acoustic treatment, but in the other entertaining spaces is there anything that anyone would recommend?  We plan to use "Akupanel" in a couple of places,  although I've realised that for this to be effective you really need to put it on battons/insulation, rather than surface-mounted on top of plasterboard.   We can't use this everywhere though, so wondering if there is a simple alternative to standard PB/skim that we could use for ceilings that don't break the bank?

 

Come across these products, but no idea how avaialable they are or what they cost:

- https://www.quietstone.co.uk/product/quietspray/

- https://www.stil-acoustics.co.uk/Seamless-Acoustic/Acoplaster.html

- https://fadeceilings.com/product/plus/

 

 

 

What about the doors to the room? If you have kids then they need the toilet and leave their bedroom door open, when we get a bit older we like to go to the bog as the bathroom window has the best view of the moon.

 

The internal doors get opened and left so unless they are teenagers and never come out the room, so who cares if they hear what you are listening to?  If you are entertaining then if your pals "like a drink" they too open doors, some will even leave the bog door open.. maybe best not to invite them back? 

 

Unless you are say a professional musician or are sensitive to noise (I'm pretty deaf) then I would make sure that if you are self building you don't get carried away with this level of internal sound insulation, the time (labour) and cost implications unless you have plenty cash. If you have that amount of cash you can afford a comprehensive redesign.

 

Material prices etc are going through the roof at the moment. Many homes change.. you may have kids.. they go..but more than likely the noise from outside will increase over time and that could be something that you maybe want to future proof for? rather than the short term.

 

Being blunt if you do come to sell then a buyer will be much more interested in what they can hear from outside rather than in between the rooms as you won't be having a party when you are selling the house.

 

If it is a "forever home" then you maybe want to look long term.. maybe spend more on the envelope insulation, the quality of the roof and weathering details?

 

In this climate as a renovator / self builder it may be worth just hedging your bets on the fabric that will add real easily measurable value. In other words the stuff a valuer will appreciate. Your big speakers.. maybe an extra fiver on the valuation.

 

Do you have bifold doors? If so bet you have a lot of frame / vs glass area. For an extra say £ 1500 - 2000 quid you could get some true sliding doors (not the lift and slide type with the massive handle) with a 20 mm thick mullion.. you are as close to frameless glazing as you can get here.. value wise? each to their own but a buyer will appreciate maybe more than a bit of noise between the rooms?

 

 

 

 

 

 

[tanneja]

On 19/04/2021 at 18:10, Dan F said:

 

These are the links our MVHR guy sent us:

 

https://www.holyoake.com/product-details/LDO-T_item.html
https://www.koolair.com/en/catalogue/unidades-de-transferencia-de-aire-acustica-kat/#guia_seleccion
https://www.specifiedby.com/waterloo-air-products-plc/dsr-acoustic-air-transfer-grilles

On the opposite side of one of the (block) walls of our planned cinema room is the under stairs cabinet.  It will house the UFH manifold, energy smart meter and a fuse board.  The cupboard will have a door accessible from the hallway.  Would it be nonsense to  have a standard air transfer grill from the cinema to the understairs area and then try to muffle the sound in there with some kind of soft products on the underside of the stairs, with the airflow permitted underneath the under stairs door?  All of this follows on from the cinema room being air sealed besides an MVHR inlet.  Am considering brining an MVHR extract into that room to make it self contained, but this also feels like an option.