Home cinema ideas/questions

[Jowsey]

I don't mean to sound insulting but have you posted this on AV Forums? There is literally a forum for home cinema building and then a sub-forum for DIY home cinema building!

Linky!

[Dashers]

If you don't want to go full on nuts, I'd pull up the floorboards in the room(s) above and get some tightly packed acoustic insulation from your favourite builders yard inbetween the joists. This won't sound-proof, but it will absorb a lot of the vibrations moving through the air.

I'd also ditch your Atmos plans of having ceiling speakers, called me old fashioned but I've never felt the need for sound above unless you're planning on a lot of vertical shooter games or something. Surround sound fills things out nicely but it shouldn't be pin-pointable, and once the volume is up, I'm not sure it's going to add a lot (not that I've experienced it yet).

The problem with in-ceiling speakers is you have a direct physical connection to the upstairs rooms and bugger all between the back of the speaker and the floor above - and speakers pump out sound in both directions just as powerfully.

I'd still look at either cracking open the stud walls (easy job with a crowbar) and stuffing them with acoustic insulation as above. Then have the new panels reattached with resilient bars to reduce transmission (you could do this on the ceiling too, but ceilings always seem like too much hard work to me).

If you have brick walls, then you can mass load by building a stud directly off them and stuffing them again. You lose a bit but not quite as much as a proper room in a room.

Room shape does matter for good acoustics, but you can do other things to break up reflections such diffusers and plenty of furniture and a healthy does of acoustic panels at the first reflection points and bass traps in the corner.

I want to do all this, but I've never been bothered. I've had one ceiling/floor sound-proofed and the sound goes up the walls and around the edge of the sound-proofing. It's still a lot better than without though.

[neonplanet40]

I don't mean to sound insulting but have you posted this on AV Forums? There is literally a forum for home cinema building and then a sub-forum for DIY home cinema building!

Linky!

I've already posted on there mate. But, if I'm honest, I always come to Hexus for advice because it has ALWAYS been very helpful regardless of the topic.

[neonplanet40]

Going to read through your replies now guys before I post a stupid comment

[neonplanet40]

Thanks for the replies guys. back to the drawing board. As this room has been converted from a garage, maybe they put a lot of insulation in already

Maybe when I install the sound system etc the room will already be quite good at isolating sound . . . maybe . . .

I will revisit this when I move in and go from there when I can accurately hear how much sound is escaping and what the likely impact of this will be!

Thank you

[scaryjim]

... I will revisit this when I move in and go from there when I can accurately hear how much sound is escaping and what the likely impact of this will be! ...

Excellent plan If it's a conversion from a garage it should at least be proper brick walls, which will help.

[neonplanet40]

That, I'm not so sure about.

The house is:

172 m² and "The main walls comprise a structural timber frame with cavity and
rendered masonry to external skin."

It is now quite common in Scotland for houses to be timber framed.

So I doubt there are any brick walls in the conversion

If I'm honest, good brick walls was something I was keen to get when buying a house but literally every one we viewed was timber framed.


Also:

I guess getting something like this: http://www.noisestopsystems.co.uk/wa...ing-wall-board
And drilling it into the walls (and ceiling) and then sticking this:

https://www.scan.co.uk/products/scan...NkdRoCZK7w_wcB

Around the room wouldn't work? I am aware the acoustic tiles would need more care.

However, if the above worked, it seems doable. Even by me! But no doubt I am missing something.

PS - My physics never was great

[eltel]

If you have a local CCF branch (part or the Travis Perkins group) near to you may I suggest you give them a visit as they specialise in what you are trying to do and are got with the advice you need and the materials as well.
and no I don't work for them but I do contract maintenance on the Travis Perkins group sites
hope this helps you in your quest
regards eltel

[Smudger]

We recently had our garage converted, and that required putting a stud frame inside the brick walls and filling with insulating foam. This is a requirement apparently, for stopping heat-leak, and for fire retardation. If yours was a recent conversion, it may be that you might already have this insulation in. Not sure how it is for sound, but heat travels in waves, doesn't it?
Ours is an outside garage, attached by a porch, so all the walls are brick. Only one skin with no breeze block though.

[scaryjim]

... if the above worked, it seems doable. Even by me! But no doubt I am missing something. ...

Possibly the cost? The wall panels are 1.2m x 1.2m, so in an average sized room (based on my living room ) you'd need ~ 34 panels to do the walls and ceiling - that's £1250

Plus each panel weighs 45kg, so you'd need specialist props to hold them up whilst drilling or sticking them - and incidentally, screwing them to the existing walls would introduce a physical coupling between the surface panel and the main wall, which would reduce the effectiveness - I imagine that's why they recommend sticking the panels up with a suitable adhesive.

The foam looks like it's only really effective at absorbing high frequnecy sounds so you'd still have all that rumbly bass to cope with. Plus it would seriously impact the room acoustics. And - again based on my living room - you'd need around 12 packs to do the whole room @ another ~ £850.

I mean, you're definitely thinking along the right lines, but I can imagine what my other half would say if I suggested dropping more than £2k just on the base materials for soundproofing a room ...

[Lowe]

OK - if I may weigh in a little here. If you don't know, I'm an audio engineer who also happens to have more than a passing interest in home cinema...

As it's been eluded to above there are two sides to acoustic treatments; isolation and reverberation.

Isolation as the name suggests concentrates on looking at stopping the transmission of sound from one area to another. Since sound travels through solids way better than it does through air, this means it's nigh on impossible to stop all transmission. It is also very much frequency dependent, higher frequencies are many orders easier to stop compared with very low frequencies, due to the amount of air being moved. I can tell you now that adding rock wool insulation to the walls is a start, but in the grand scheme of things will be ineffective. The two most effective isolation methods are air gaps, and sheer physical hung mass. You can get dedicated products for this - Google for mass load vinyl. The other method is an air gap between two walls, creating a 'room within a room'. Combine this with a hung mass loaded vinyl in-between the walls and you're starting to get somewhere. Unfortunately this isn't really all that cheap, and even with all of this the absolute best isolation that you'll probably achieve is somewhere in the region of 75dB. Something to consider before you start smashing the credit card...

The other side to acoustic treatment is reverberation. When sound strikes a surface some energy is imparted in to the material, and some is reflected. Depending upon the frequency and the material involved the amount reflected differs. Essentially though a material that has significant mass that is hard will reflect, whereas soft fibrous materials tend to absorb. Plasterboard and bricks tend to be in the former category, and so whilst you can have the most brilliantly isolated empty room it will sound horrific if you play music in it because the sound is bouncing all over the room and blending with the sound that's coming from your source (i.e loudspeaker). With transient sounds in smaller spaces this manifests as a fluttery echo. Simply clap your hands and listen. Since loudspeakers are point sources that are semi directional you don't need to cover every single square inch with deadening material, but bare in mind with a multichannel surround array you aren't just firing audio in one direction, and compared to a more typical stereo system you do need to put a little more effort in than you otherwise might. The first thing to do is carpet the floor, and don't skimp on the quality. Avoid laminate/tiles etc since you're just adding to the problem. Add plenty of soft furnishings - sofas, cushions, beanbags etc, they will all help. Clap your hands again in your basically treated room and mentally compare to when it was empty - hopefully you'll start to hear a difference. If not, it's time to start adding in foam panels etc. Bare in mind that pyramid rippled acoustic foam is very wife unfriendly, since it only normally comes in a drab grey colour. However you can make your own panels by making up a wooden frame, covering and stapling coloured fabric across the front (think a bit like canvas prints), then filling the back with high density fibre Rockwool. Put some chicken wire across the back to hold it in place and Bob's your Mother's Brother. Simple to make and effective - hang them on the walls and away you go. Best places to start hanging panels are at the first reflection points - so these are the points where if you were stood where each speaker will go, approx 60 degrees in a cone to the nearest wall, with the middle of the panel being the height of the tweeter. If you're able, do this for all of your speakers. Once done, do the clap test again... The final thing you may consider is adding in a diffuser. A diffuser doesn't absorb the sound, it just reflects it in a random direction. There's various different designs - I really like skyscraper diffusers since they work and have the added bonus of looking ace! Consider putting one along the back wall behind where you sit.

Oh - and that's another thing. Don't sit along the back wall. Your seating position should be about 3/4 of the way back. Also from an audio perspective ensure you orientation down the length of the room, not the width.

Lots to take in there - if you do need any help just shout.

[neonplanet40]

OK - if I may weigh in a little here. If you don't know, I'm an audio engineer who also happens to have more than a passing interest in home cinema...

As it's been eluded to above there are two sides to acoustic treatments; isolation and reverberation.

Isolation as the name suggests concentrates on looking at stopping the transmission of sound from one area to another. Since sound travels through solids way better than it does through air, this means it's nigh on impossible to stop all transmission. It is also very much frequency dependent, higher frequencies are many orders easier to stop compared with very low frequencies, due to the amount of air being moved. I can tell you now that adding rock wool insulation to the walls is a start, but in the grand scheme of things will be ineffective. The two most effective isolation methods are air gaps, and sheer physical hung mass. You can get dedicated products for this - Google for mass load vinyl. The other method is an air gap between two walls, creating a 'room within a room'. Combine this with a hung mass loaded vinyl in-between the walls and you're starting to get somewhere. Unfortunately this isn't really all that cheap, and even with all of this the absolute best isolation that you'll probably achieve is somewhere in the region of 75dB. Something to consider before you start smashing the credit card...

The other side to acoustic treatment is reverberation. When sound strikes a surface some energy is imparted in to the material, and some is reflected. Depending upon the frequency and the material involved the amount reflected differs. Essentially though a material that has significant mass that is hard will reflect, whereas soft fibrous materials tend to absorb. Plasterboard and bricks tend to be in the former category, and so whilst you can have the most brilliantly isolated empty room it will sound horrific if you play music in it because the sound is bouncing all over the room and blending with the sound that's coming from your source (i.e loudspeaker). With transient sounds in smaller spaces this manifests as a fluttery echo. Simply clap your hands and listen. Since loudspeakers are point sources that are semi directional you don't need to cover every single square inch with deadening material, but bare in mind with a multichannel surround array you aren't just firing audio in one direction, and compared to a more typical stereo system you do need to put a little more effort in than you otherwise might. The first thing to do is carpet the floor, and don't skimp on the quality. Avoid laminate/tiles etc since you're just adding to the problem. Add plenty of soft furnishings - sofas, cushions, beanbags etc, they will all help. Clap your hands again in your basically treated room and mentally compare to when it was empty - hopefully you'll start to hear a difference. If not, it's time to start adding in foam panels etc. Bare in mind that pyramid rippled acoustic foam is very wife unfriendly, since it only normally comes in a drab grey colour. However you can make your own panels by making up a wooden frame, covering and stapling coloured fabric across the front (think a bit like canvas prints), then filling the back with high density fibre Rockwool. Put some chicken wire across the back to hold it in place and Bob's your Mother's Brother. Simple to make and effective - hang them on the walls and away you go. Best places to start hanging panels are at the first reflection points - so these are the points where if you were stood where each speaker will go, approx 60 degrees in a cone to the nearest wall, with the middle of the panel being the height of the tweeter. If you're able, do this for all of your speakers. Once done, do the clap test again... The final thing you may consider is adding in a diffuser. A diffuser doesn't absorb the sound, it just reflects it in a random direction. There's various different designs - I really like skyscraper diffusers since they work and have the added bonus of looking ace! Consider putting one along the back wall behind where you sit.

Oh - and that's another thing. Don't sit along the back wall. Your seating position should be about 3/4 of the way back. Also from an audio perspective ensure you orientation down the length of the room, not the width.

Lots to take in there - if you do need any help just shout.

Thanks for the reply Lowe!

Do you do installs haha

[royo]

Some useful links:

http://www.soundproofingcompany.com/...within-a-room/
http://www.soundproofingcompany.com/...roofing-walls/

I've definitely seen the fiberglass insulation work wonders and I would pair that up with mass loaded vinyl (instead of the green glue shown above) and some high density plasterboards.

[Lowe]

Thanks for the reply Lowe!

Do you do installs haha

Only for myself

[Macman]

Neonplanet - just throwing this out here, you checked out Reddit? Perhaps - https://www.reddit.com/r/hometheater/

I've seen some nice builds been posted on Imgur too.

[Dashers]

Only for myself

Wow, that's a big screen! Epic.

Have you done anything special to cater for your speakers being packed into the corners?