The Little Cinema of Burnley

I think I saw Neil Davidson use a blue acoustic foam in the build he showed us here, so maybe that stuff would be better if you could track it down.
Thanks, I've been looking for the blue variety again (pretty sure I found it before) but haven't come across it today.

I presume you're referring to this post - Ultra High End AV UK Style - well remembered if you were, although there is no product detail and the images are missing :( I'll be cheeky and tag @Neil Davidson in any case :)
 
Yes, that was the one. Hopefully Neil will have the time to respond and point you in the right direction.
 
My thoughts from my reading of all the info on the AVS forum and the Building a Home Studio book.

Insulation is the least important of the four pillars of sound proofing. If your structure is 'decoupled', has decent 'mass' and has 'damping' through Green Glue or similar the insulation doesn't need to have much mass. Solid insulation just provides potential for short cutting your decoupling. Indeed, on most of the massive builds on AVS, they generally use the cheapest 'pink fluffy' insulation they can get.

As for expanding foam, I'm not sure where you're thinking about using it, but doesn't it set hard? If so it won't work in the same way as acoustic chalk. If you're thinking of where the door joins the decoupled structure, this is the one place where it says it's ok to join the two. Better to have a coupled structure here and a door with lots of mass than anything else.
 
Insulation is the least important of the four pillars of sound proofing. If your structure is 'decoupled', has decent 'mass' and has 'damping' through Green Glue or similar the insulation doesn't need to have much mass. Solid insulation just provides potential for short cutting your decoupling. Indeed, on most of the massive builds on AVS, they generally use the cheapest 'pink fluffy' insulation they can get.
Insulation might be the least important of the 'four pillars' of sound proofing, but it's still important. I had thought about stuffing these gaps with rockwool, but I imagine acoustic sealant / mastic / chalk / foam would be more effective.

As for expanding foam, I'm not sure where you're thinking about using it, but doesn't it set hard? If so it won't work in the same way as acoustic chalk. If you're thinking of where the door joins the decoupled structure, this is the one place where it says it's ok to join the two. Better to have a coupled structure here and a door with lots of mass than anything else.
There is a gap behind the existing door frame and the brick wall, pretty much all round. This has been fitted square by using packers, and then the gaps filled with expanding foam (yellow).

The existing door frame will need to come out as it doesn't come far enough in to the room now, and so I will need to fill those gaps again. I just don't think acoustic sealant is going to cut it, as most products state a maximum gap of 50mm (I have seen some that do claim more), and the gap is greater in some places. If I'm going to use expanding foam, then I might as well use a product that claims some acoustic properties.

Pretty sure jfinnie has or was going to use foam for exactly the same purpose, so will take another look at his build thread.
 
This is the acoustic flexi foam the builders used at mine, but mostly for sealing big holes:
https://www.screwfix.com/p/soudal-f...gclsrc=aw.ds&dclid=CK2fxdGqutsCFcGNGwod-nsBUg

There is a bit around the door frame, but mostly the door frame is on the stud structure.

I do think they regard it really as "acoustic" from the point of "airtight", not necessarily "decoupled". It is a bit flexible.

I can see the logic in using the fluffy insulation - I'm sure there will be somewhere that I have insulation touching the wall and shorting a little. Less of an issue for you with your nice resilient channel. Really looking forward to hearing (or not!!! :) ) how that has worked out for you.
 
This is the acoustic flexi foam the builders used at mine, but mostly for sealing big holes:
https://www.screwfix.com/p/soudal-f...gclsrc=aw.ds&dclid=CK2fxdGqutsCFcGNGwod-nsBUg

There is a bit around the door frame, but mostly the door frame is on the stud structure.

I do think they regard it really as "acoustic" from the point of "airtight", not necessarily "decoupled". It is a bit flexible.

I can see the logic in using the fluffy insulation - I'm sure there will be somewhere that I have insulation touching the wall and shorting a little. Less of an issue for you with your nice resilient channel. Really looking forward to hearing (or not!!! :) ) how that has worked out for you.
Thanks, I did look at that foam, but other than the acoustic logo on the can there is no mention of its capabilities. I notice though that it is 70% Open and 30% Closed Cell, whilst the other Soudal one I linked to in post 149 is 30% Open and 70% Closed Cell, but states 60dB acoustic rated!
 
Thanks, I did look at that foam, but other than the acoustic logo on the can there is no mention of its capabilities. I notice though that it is 70% Open and 30% Closed Cell, whilst the other Soudal one I linked to in post 149 is 30% Open and 70% Closed Cell, but states 60dB acoustic rated!
The thing I "liked" about it was the flexibility, as I understand most of these foams cure pretty rock hard.
 
The thing I "liked" about it was the flexibility, as I understand most of these foams cure pretty rock hard.
From my limited research, it seems that the Closed Cell variety sets rock hard, whilst the Open Cell stuff remains fairly malleable. This difference, I assume, is why Open Cell is recommended for sound proofing - but what confuses me is why the stuff I linked to (70% Closed Cell) quotes 60dB acoustic rating, and the stuff you linked (70% Open Cell) doesn't appear to quote any figures :confused:
 
This difference, I assume, is why Open Cell is recommended for sound proofing - but what confuses me is why the stuff I linked to (70% Closed Cell) quotes 60dB acoustic rating, and the stuff you linked (70% Open Cell) doesn't appear to quote any figures :confused:
Who knows what 60dB means anyways... lol
In any case, the technical data for Flexifoam seems to list 60dB also.
See here:
Soudal: Expertise in sealants, PU foams and adhesives
http://www.soudal.com/soudalweb/images/products/1908/ID1999_Flexifoam Gun_Belgium_English.pdf
Note I didn't see this originally and just went for headline "flexible + acoustic = one mug parted with money..."!
"- Vibrating constructions
- Use as fixing foam while minimizing noise transmission
- Impact and shock damping"

Does sound ideal though. Note the comment on moistening the surfaces before applying. I don't think I saw my builders doing that.
 
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IIRC, one of the reasons insulation like 'pink fluffy' work is because any sound that hits the fibres as it travels through the cavity changes direction and gives up sound energy as it does that - actually turning it into heat, though not as huge amounts - you won't burst into flames if the volume is too high :)
 
IIRC, one of the reasons insulation like 'pink fluffy' work is because any sound that hits the fibres as it travels through the cavity changes direction and gives up sound energy as it does that - actually turning it into heat, though not as huge amounts - you won't burst into flames if the volume is too high :)

I've got in to numerous discussions with guys far more knowledgeable than myself over on Gearslutz and John Sayers forum, and the takeaway seems to be that it really doesn't matter. Yes, insulation vs no insulation is preferable, but what you actually use won't make a huge difference... so just go with the cheapest variety.

From what I was told, unless you are building really, REALLY thick walls, any insulation will only absorb frequencies above 400hz, which is going to be completely blocked by the plasterboard. Using dense insulation will not provide any better isolation at low frequencies, the only ones that will escape. The insulation in the wall cavity is there to stop the wall from vibrating sympathetically with the sound. It takes LOTS of mass to stop low frequencies, and insulation at the thickness we are talking about just can't stop it. In theory, you would need a wall of insulation 1/4 wavelength to absorb 100% of the sound. That's over 2m thick for low frequencies. So for a standard wall where you're using a decoupled MSM system with brick and plasterboard, you should just put whatever is cheapest in the wall.

This is what I was told anyway... acoustic science makes my head spin sometimes lol! o_O
 
Yeah, without the insulation the space just becomes a resonance cavity, so it helps there too. When you see the STC values for various types of wall construction, it's always better with pink fluffy or similar inside, and the STC doesn't measure resonance, just sound transfer, so it's definitly doing something.
 
Excellent work my friend ! what are you doing with your floor ? as i have had a major issue with mine after 12 years i have had damp travel from my garage into cinema room i had to take out nearly half the room check it out on here " movie room 5.0 "
 
Excellent work my friend ! what are you doing with your floor ? as i have had a major issue with mine after 12 years i have had damp travel from my garage into cinema room i had to take out nearly half the room check it out on here " movie room 5.0 "
Thanks John, and sorry to hear you have had problems. Have you tracked the source of the damp?

The floor was put in when the garage was converted at the back end of 2010, and I have not touched it. It's a 'floating floor' design, constructed from a stud frame sat on top of kiln dried sand, filled with kingspan insulation slabs, and mdf boards on top. It raised the floor level about 8 inches to match the rest of the house. A damp proof membrane sheet was installed under the sand and wrapped up the walls to just above floor level.

I also removed the original garage door, and replaced with a brick wall and window etc., so there shouldn't be anywhere for damp to penetrate... hopefully!
 
you should put a under floor sub in that i will show you when i have finished mine in a few weeks i will put pictures on my thread. I think the damp problem was due to cold bridging or my boiler which is in the garage, i have been dry with no damp yet or it was due to me stuffing offcuts of iunsulation in between the joists to cause cold bridging, when i'am finished you will have to come over and have a listen.
 
Whether it was right or wrong I built another door liner within my inner wall and left the original door liner in place, leaving about 5mm gap, which I filled with silicon to match the stain I used.
 
Right, it's high time that I updated the thread with progress as it has been a while :blush: There has been progress, albeit not as much as there should have been due to the great weather we had in June and July, the World Cup, summer holidays and work etc. All excuses I know, but that's life.

I mentioned back in post 148 that I needed to build some frames to go around the mains consumer unit and water meter panel so that they could be boxed in. The method was pretty much the same as the ceiling speaker back boxes; MDF on the outside, Soundbloc on the inside, with Green Glue sandwiched in between.

This is what it looked like before -
20180610_153853.jpg


And with the frame fitted -

20180623_152858.jpg


I decided to line the face of the breeze block with some of the leftover neoprene acoustic tape, and filled all the gaps with acoustic sealant. The frame was then pushed in to place and sealed with the acoustic adhesive I'd used around the window.

I'll fit some slim architrave around the edge of the frame to finish, along with a push catch door so there are no handles on show.
 
You may remember that I got some 'acoustic and fire rated' back boxes for the double sockets, that probably had no soundproofing properties whatsoever -

WA4235.jpg


So I took the advice given by a few at the time, and lined them with some putty pads -

20180721_102740.jpg


20180721_103502.jpg


And fitted in the wall -

20180621_223959.jpg


I did say that the boxes were going to be fixed to noggins, but as these are drywall boxes noggins were not required. Will be interesting to see how the spring loaded lugs fare against the double plasterboard though!
 
It was then time to cut some holes in the ceiling, and hope that I'd find the back boxes.....

20180722_144423.jpg


Phew - all present and correct :clap::clap::clap:

One of the boxes had become detached from the ceiling so needed a bit of acoustic adhesive and clamping for 24 hours.
 
Have you tried fitting sockets to the back boxes yet? I have the same boxes and the answer to the question "how do they deal with double plasterboard" is "not at all". I only have them in the ceiling (the rest are in MDF skirting) but I had to gouge out a load of the 2nd layer of board to make a "hole" for the lugs to sit in.

Part of the problem is the channel that the lugs sit in is only long enough for a single layer of board. So with 2 layers of board the lugs won't actually stay at the sides of the box.
 
I was getting fed up with plaster dust and looking at 'pink' walls, so time for a mist coat

20180805_114352.jpg


This made the room so much brighter, and I was tempted to leave it white - seems a good colour for a cinema room, doesn't it?!

Well no, of course not...

20180810_192045.jpg


A couple of coats of Valspar Tempest's Teapot later and the room now looks like a cinema!
 
Have you tried fitting sockets to the back boxes yet? I have the same boxes and the answer to the question "how do they deal with double plasterboard" is "not at all". I only have them in the ceiling (the rest are in MDF skirting) but I had to gouge out a load of the 2nd layer of board to make a "hole" for the lugs to sit in.

Part of the problem is the channel that the lugs sit in is only long enough for a single layer of board. So with 2 layers of board the lugs won't actually stay at the sides of the box.
No not yet, but I saw your post about this on another thread so have been thinking about it.

Wrapping the boxes in putty has made for a very tight fit in the cutout, so they may actually be fine as is, but will see.
 
No not yet, but I saw your post about this on another thread so have been thinking about it.

Wrapping the boxes in putty has made for a very tight fit in the cutout, so they may actually be fine as is, but will see.
Hope they work out. The tricky bit is keeping the screw thread hole perpendicular to the socket you're installing. If the board material is thin enough it works well because the spring lugs lock into the channel at the sides, but that doesn't work with thick material and the lugs end up being pushed out at an angle.
 
In the mean time, here are some photos of the backer boxes I've made for the in-ceiling Atmos speakers. Now I'm not going to lie, they don't look great, but they will do the job and will never been seen anyway!

Hey @adam-burnley thanks for sharing your build with me.. Really am enjoying seeing your progress.. That said I have just realised I have a major problem...

My room is already done. The original purpose was an office/cinema room. I never planned on a surround sound system as I figured my Yahama YSP 2500 Soundbar would be enough... WRONG. EvEven thought projects sound to create a surround sound effect, it just does not cut the mustard!

So now I want a 5.1.2 Atmos setup.... Problem is my Garage is a flat roof. Already plastered ect... How am I going to get a back box in the roof without destroying my roof!!

Hindsight is a wonderful thing!

Sorry, not intended on hijacking your thread.

Good luck with your build though!
 
@Flyboy583 - when you say the garage is a flat roof, do you mean there isn't another room above it?

You only really need a back box if you want to prevent sound leakage, is this a concern? if not, and there isn't a habitable room above the garage, then you don't really need anything really. If there is a habitable room above, then you should at least use a speaker hoody so that you maintain the ceiling's fire protection integrity. Hoody's can be fitted easily, unlike a back box which would require a lot of work to retrofit.
 

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