The Room With(out) A View. A 7.1.4 DIY ground-up cinema build

Harkon321

Well-known Member
Nice build to follow.

Few things I'll mention but feel free to ignore or whatever, just my 2p.

If you're embedding speakers in the walls, then build backer boxes (you may already have planned this). Seeing as you are spending a fair bit on sound proofing. If you're not isolating the stud work or using clips and channel, then not sure I'd both with Green Glue.

Glazed door will look good, but light will be an issue, even with a curtain to be honest. Also means you can't fix any panels or anything to the door, and it'll be very 'reflective'.

I've got a single row of three, and a row behind me would be pointless without a riser as you would not see the screen, unless front row fully reclined.
 

batfink007

Active Member
Nice build to follow.

Few things I'll mention but feel free to ignore or whatever, just my 2p.

If you're embedding speakers in the walls, then build backer boxes (you may already have planned this). Seeing as you are spending a fair bit on sound proofing. If you're not isolating the stud work or using clips and channel, then not sure I'd both with Green Glue.

Glazed door will look good, but light will be an issue, even with a curtain to be honest. Also means you can't fix any panels or anything to the door, and it'll be very 'reflective'.

I've got a single row of three, and a row behind me would be pointless without a riser as you would not see the screen, unless front row fully reclined.
Thanks.

Plan is to build speaker boxes and then embed those in the wall. Do you think green glue around those would be worthwhile? (as I said above, I'm not hugely confident I'll be able to source the DIYSoundgroup speakers, but I'm keeping my fingers crossed).

There will be a 'lobby' between the glazed external door and the cinema room, so no direct light. Based on the comments above, a curtain on the partition is probably the way I'll go.

Yes, I'm worried about the 2nd row. I might be able to build a small riser, will have to wait and see whether getting in/out of the chairs and the position of the atmo speakers makes it possible. Alternative might be to stagger the chair position, or maybe settle for 5 seats. We shall see. Once I'm water-tight / weatherboarded I plan on laying things out in sketchup before doing too much on the inside (except for the 1st 70mm insulation layer, which can go in now).
 

Harkon321

Well-known Member
I used Green Glue on all my backer boxes. They are small areas so can't hurt. It's just choosing where you draw the line. Mark (Shed of Darkness) didn't use Green Glue, and I'm almost certain you wouldn't hear that from 100m away. Shed of Darkness 9.4.6
 

Triggaaar

Distinguished Member
If you're embedding speakers in the walls, then build backer boxes (you may already have planned this). Seeing as you are spending a fair bit on sound proofing. If you're not isolating the stud work or using clips and channel, then not sure I'd both with Green Glue.
Why's that? The green glue provides damping, which is beneficial separate from isolation.
Plan is to build speaker boxes and then embed those in the wall. Do you think green glue around those would be worthwhile?
For my cinema, I'm building a room within my existing room. I'll build isolated stud walls and ceiling, with osb, Tecsound, plasterboard. Where I cut into those sections, to place speakers, I will have OSB, Tecsound, + green glue and plasterboard, so more than the rest of the walls. That's because there won't be a few inches on insulation behind the speaker boxes, which will be close to my existing walls, so I don't want the speaker areas to be too much of a weak point. I expect these additional things will help a bit, and obviously the green glue just around the speakers is not much of an expense. I'll also be using it on the doors and some other weak areas.

Yes, I'm worried about the 2nd row. I might be able to build a small riser, will have to wait and see whether getting in/out of the chairs and the position of the atmo speakers makes it possible. Alternative might be to stagger the chair position, or maybe settle for 5 seats. We shall see.
Unless forced to, I wouldn't bother with a second row if it's not raised in some way. I'd just have the opening at the edge of the back wall, so you can walk past the back row which would be on a raised platform.
 

Harkon321

Well-known Member
Why's that? The green glue provides damping, which is beneficial separate from isolation.

It's the guidance I read from the Soundproofing Company who sell Green Glue. I understand the role that each component has, and how they differ, but I understand their reasoning why.

Beyond just adding mass, arguably the best way to stop the lowest frequencies is isolation. If you can stop that transmission through material and force it travel through the air gap, it makes a huge difference. Lots of graphs to show this but I imagine I'm preaching to the converted. The damping compound of Green Glue is also very effective at those low frequencies but compromised if you skip isolation.

I did just this on my ceiling. Didn't use clips and channel but used Green Glue. I'm certain that the Lfe performance would have been much better has I isolated the ceiling.
 

Triggaaar

Distinguished Member
It's the guidance I read from the Soundproofing Company who sell Green Glue. I understand the role that each component has, and how they differ, but I understand their reasoning why.
Ok. I don't :)

The damping compound of Green Glue is also very effective at those low frequencies but compromised if you skip isolation.

I did just this on my ceiling. Didn't use clips and channel but used Green Glue. I'm certain that the Lfe performance would have been much better has I isolated the ceiling.
I'm not sure I follow. Yes of course I agree that your ceiling performance would have been much better if it had been isolated. But would it have been no worse if you'd removed the green glue?

The relevant comparisons are obviously the starting point (a standard wall), and
a) isolated mass
b) isolated mass, also with the use of green glue
c) mass
d) mass, also with the use of green glue

The results from best to worst are probably b), a), d), c), but how much better each option is I have no idea. Is the benefit from a) to b) really better than the benefit from c) to d)?
 

Harkon321

Well-known Member
When I was reading, I think the point was the difference adding Green Glue made to a non-isolated mass weren't significant enough.

This guy has built more rooms in the states than I care to mention.

Back to your question, Green glue for a room costs more than clips and channel so if you are skipping the isolation to save money but have the money for GG you should use your green glue budget to add the clips and channel and skip the GG. Green Glue does work between drywall and plywood. But hanging the damped mass wall directly on the studs compromises the entire sound isolation design. There will be some benefit of just doing the Green Glue put you need to set your expectations really low.

To green glue or not?
 

Triggaaar

Distinguished Member
When I was reading, I think the point was the difference adding Green Glue made to a non-isolated mass weren't significant enough.
Yeah if they've tested and that's the case, then that's great info.


Back to your question, Green glue for a room costs more than clips and channel so if you are skipping the isolation to save money but have the money for GG you should use your green glue budget to add the clips and channel and skip the GG. Green Glue does work between drywall and plywood. But hanging the damped mass wall directly on the studs compromises the entire sound isolation design. There will be some benefit of just doing the Green Glue put you need to set your expectations really low.
Great stuff.

Now I want a refund on all the Green Glue you sold me :rotfl:
 

batfink007

Active Member
I don't think anyone builds their speakers better than Matt, but I don't think the Volt 10s are the best of DIYSG's range.
Seems we're hard pressed to get any DIYSG speakers right now anyway. I may have to consider other 7.(1).4 options....
 

batfink007

Active Member

Harkon321

Well-known Member
In my dig below there was quiet a bit of discussion about mini split ac units like that. Mitisubushi zen being popular and the one I got quotes for. Not fitted it yet but have cables for it; will see how the summer goes.
 

batfink007

Active Member
In my dig below there was quiet a bit of discussion about mini split ac units like that. Mitisubushi zen being popular and the one I got quotes for. Not fitted it yet but have cables for it; will see how the summer goes.
Thanks. Will look into these. Do you know if they are (competent) DIY, or do they require an engineer to install (I would guess yes for warranty purposes)?
 

batfink007

Active Member
Door has arrived. Job for the weekend !

IMG_2414.jpg
 

Harkon321

Well-known Member
All the ones I looked at required professional install. Certificate etc. There are a few DIY options that come pre gassed but the ones I found were nowhere near as quiet. Mine was in room though. If you added a second door you could have it in the lobby with the projector and then duct it in. Google Deadvents if you want it really quiet.
 

batfink007

Active Member
All the ones I looked at required professional install. Certificate etc. There are a few DIY options that come pre gassed but the ones I found were nowhere near as quiet. Mine was in room though. If you added a second door you could have it in the lobby with the projector and then duct it in. Google Deadvents if you want it really quiet.
Thanks. I did originally plan a deadvent (well, a vent at least) when i was thinking of using a all-in-one wall mounted unit, but when I started looking at the split units I'd hoped it was something I could avoid. Hmmm.... something else to ponder.
 

Harkon321

Well-known Member
I wonder if you could put the split in the lobby and then two inline fans. One to draw air from the lobby and another to throw it out. Depends how far you want to go.
 

mb3195

Distinguished Member
Your build is coming on great, but if you don’t have an internal door you are going to compromise everything about it. Sound quality will suffer, bass will be really difficult to control (you’ll get a significant build up in the porch are), lighting will be a major issue and sound proofing will be terrible through just a pvc door, an internal door here makes a significant difference. In my build, my external door is my weakest area by a long way with sound proofing, when my internal door is open you can hear a lot more from the outside than when it is shut.

Just my 2 cents......
 

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