imightbewrong's 2022 garden cinema project

[imightbewrong]

So some combination of mid-life crisis and the upgrade bug has me pulling the trigger on a garden room cinema project. Starting this thread to get some advice/opinions/pointers on making it all work. First, the current system - mostly around ten years old, other than the projector:

Audio: 2xB&W 805S standmounts as fronts, matching HTM4S center. 2x B&W M1s as rears. No sub.
Amp: Arcam AVR600
Video: Sony HW40ES projector, 106" drop-down screen, Pioneer 50" plasma
Source: Denon 2500BT / nvidia shield
All in a c. 4x4m living room

The plan is two-fold:

- Build a c. 7.5x4.5m (external) timber dedicated/mostly dedicated room at the bottom of the garden.
- Upgrade most/all equipment to a 4k picture/Atmos etc audio with an audiophile component.

These could happen on somewhat different timescales, with the equipment being upgraded over time once the room is in.

We are a family of six - would be looking to have decent seating for maybe eight to ten? Could be a combination of individual seats and a more flexible bench seat for putting more little bottoms on.

High-level vision for the room:

- Main attraction a JVC N7 projector firing at a large (TBD) acoustically transparent 16:9 screen, for use in CIH setup for general 16x9 content and widescreen, and 'Imax' full screen where appropriate.
- Some kind of masking?
- Dark room
- Two/three rows of seating, front row at c. minimum recommended distance. Rear rows probably raised.
- 7.1.4 (?) Atmos setup
- Amp along the lines of Arcam AVR850 / Denon AVC-X8500H OR something lower-spec with outsourced amplification for the stereo fronts
- Front speakers - really want to be able to relax to some great music in there - would love to look at something like the B&W 804 D3s
- Other speakers - keep HTM4S center, 805S as rears? New speakers for other positions (2x sides, 4x ceiling, 1xsub)
- Source - combination of UHD spinner and the Shield
- Chord DAC maybe
- Internal acoustic tuning on the walls?
- Beer fridge
- A/C
- Some ad-hoc seating so older children an go and 'hang out' down there without all facing the same way.

Have got a drawing for the shell (and a builder), with plans for decent acoustic insulation.

That's about as far as I've got - any comments welcome. I'm not a great DIY expert - wondering how much of a project this is, whether the internals will need pro work, and whether I am mad to do this without talking to a professional cinema consultant of some kind.

It begins...

 

[Peter Parker]

projector firing at a large (TBD) acoustically transparent 16:9 screen, for use in CIH setup for general 16x9 content and widescreen, and 'Imax' full screen where appropriate.

Wise choice sir

Have you decided how you're going to make the screen wall and hang the screen? I take it you won't be fitting a baffle wall but will have the speakers free standing behind. You may want to cover the cavity behind the screen with acoustic foam or similar.

- Some kind of masking?
- Dark room

The top and bottom masking is essential IMHO to have a 2.40 screen as the main screen and height guide for everything else. They can be simple back velvet covered frames that are light weight and held in place by friction or velcro so they can be quickly and easily removed. Side masking is less essential IMHO but can be simple frames again, especially if the velvet s also AT (the MVEL 22 is). Black velvet everywhere gives the best results, and you can hide the surround speakers behind black velvet grills (in columns) so nothing is on view in the room, just the projected image.

If you're going black velvet everywhere, you can build teh screen literally wall to wall and have the side wall velvet panels act as teh side masking. When the lights are down, the side walls disappear and look like a wider screen wall.

- Two/three rows of seating, front row at c. minimum recommended distance. Rear rows probably raised.

Front row at around 2x the image height of the 2.40 screen works well IMHO and puts you in the back row area of an IMAX theatre when you remove the top and bottom masking. If you use commercial cinema seats that allows you to keep the second (and third) rows closer because they take up less space. The riser height can get tall kinda quickly and cause problems with heads blocking the view from behind but you can improve this a little by staggering the rows so the heads of the second row are looking between the heads of those in front.

- 7.1.4 (?) Atmos setup

I would wire and fit for 7.1.6 and maybe even wire/fit wides just for a little bit of future proofing.

- Other speakers - keep HTM4S center, 805S as rears? New speakers for other positions (2x sides, 4x ceiling, 1xsub)

I think the surround speakers are less critical, so you could consider some that are more slimline (or even in-wall) so that they take up less aisle space and can be hidden easier. They'll also fit into the ceiling easier. Using the same type of coaxial speaker may be one route to take.

Two subs may help balance the bass out within the room better than one. You can use REW to give you a bit of an idea using the room sim that comes with it. More subs is often better

Oldroadodeon built subs into his riser and that will give more tactile feedback (like bass-shakers) so I would look into that too. He has a build thread here you could use as a guide (he also went the CIH+IMAX route).

- Source - combination of UHD spinner and the Shield
- Chord DAC maybe
- Internal acoustic tuning on the walls?

If you line the room with velvet covered frames, you can easily fit and hide acoustic treatments within them. Some people will measure and fit where necessary, some will look at first reflections, or you can use a simple approach of treating all surfaces below ear height.

That's about as far as I've got - any comments welcome. I'm not a great DIY expert - wondering how much of a project this is, whether the internals will need pro work, and whether I am mad to do this without talking to a professional cinema consultant of some kind.

It begins...

It's all DIYable, it just depends on your own ability.

Will you want to build a room with a room to try and prevent sounds coming into or leaving the room? That will remove approx 5+ ins of depth from each surface you build that way, so you can lose around a foot of the length and width.[/quote][/QUOTE]

 

[imightbewrong]

Have you decided how you're going to make the screen wall and hang the screen? I take it you won't be fitting a baffle wall but will have the speakers free standing behind. You may want to cover the cavity behind the screen with acoustic foam or similar.

Nope - this is probably the biggest question I have - do I want a baffle wall? When does one have them? Yes was probably planning to have free-standing speakers behind the screen.

Will you want to build a room with a room to try and prevent sounds coming into or leaving the room?

Current plan is to have a triple layer construction with a floating wall mounted on Genie Clips or similar to keep the noise in/out.

 

[imightbewrong]

What do people do for access to the equipment behind the screen? Put the screen on a hinge or similar?

 

[Peter Parker]

Nope - this is probably the biggest question I have - do I want a baffle wall? When does one have them? Yes was probably planning to have free-standing speakers behind the screen.

You don't have to have a baffle wall, but it can help keep a cleaner soundstage and as it prevents the bass-wave wrapping around the speakers, you get an added 6db of bass. Some speakers work better than others - those that have baffle step correction to compensate for the effect of the basswave wrapping around the cabinet will probably have a reduced output compared to those that don't. Eq will probably help in either case though.

THX baffle walls - design, build and benefits - Acoustic Frontiers

It does mean having the speakers in the right place because moving them after will be tricky, so you need to know where the seats are going to be and what the screen height is for example. If you have L&R speakers near the walls you will probably want to toe them in, and that will mean building the baffle wall with the left and right parts toed in as well.

What do people do for access to the equipment behind the screen? Put the screen on a hinge or similar?

Some people have a hinge system, but others just have the screen hanging on French cleats or similar so have to remove the screen entirely to gain access.

 

[LittleNipper]

Well, as no one has said anything in relation to construction...

Have a look at this video and the area in relation to wall construction



I could also highly recommend TechSound 50 behind or in between the plasterboard to reduce the resonance of the plasterboard. Use rockwool in between the studs. Run your cables through the studs.

If you can, celotex or similar on the floor, or more importantly in the ceiling to reduce heat loss. It is much more thermally efficient than rockwool. When I do 'offices' I would rockwool between joists/studs and 10mm celotex over ( prior to plasterboard ) this will keep the room nice and warm.

There are lot's of other things, from a construction point of view that you can do. I tend to use treated timber to construct from, even though 'it should not' be getting damp or even be in contact with damp.

Construct on top of concrete pads rather than the ground. If you are constructing new / over tree routes their are systems you can use in this scenario too.

A good 'chippie' should be able to do the whole job - less the roofing finish. I would go that route rather than a 'builder' !

 

[LittleNipper]

I have to say, it does look like someone is going to have quite a fun project to play with. I'm sure you'll ensure you get the right price on all the equipment you're planning to purchase.

 

[imightbewrong]

Well, as no one has said anything in relation to construction...

Have a look at this video and the area in relation to wall construction



I could also highly recommend TechSound 50 behind or in between the plasterboard to reduce the resonance of the plasterboard. Use rockwool in between the studs. Run your cables through the studs.

If you can, celotex or similar on the floor, or more importantly in the ceiling to reduce heat loss. It is much more thermally efficient than rockwool. When I do 'offices' I would rockwool between joists/studs and 10mm celotex over ( prior to plasterboard ) this will keep the room nice and warm.

There are lot's of other things, from a construction point of view that you can do. I tend to use treated timber to construct from, even though 'it should not' be getting damp or even be in contact with damp.

Construct on top of concrete pads rather than the ground. If you are constructing new / over tree routes their are systems you can use in this scenario too.

A good 'chippie' should be able to do the whole job - less the roofing finish. I would go that route rather than a 'builder' !

Thanks for that - watched some of the video. Current idea for the wall is two layers of 90mm Earthwool Frametherm with 50mm of Earthwool Acoustic in the cavity, with Soundbloc plasterboard internally. I guess this is C from the video, except with the cavity filled:

Maybe we should take out the internals and go for F.

Regarding the ground the current plan is actually to build on screws in the ground elevating the building above the ground slightly.

 

[imightbewrong]

I'm sure you'll ensure you get the right price on all the equipment you're planning to purchase.

I like your confidence - do you have a right price cheat sheet?

 

[LittleNipper]

Alas, I don't...

However. Magnet tend to have the cheapest plasterboard, which might seem odd. Go in, look scruffy, set up a trade account. Work out the quantity you need, add 10%, then you should get some more discount. Equally if you're buying 30-40+ sheets they will be able to deliver direct from manufacturer. They do white, blue, pink, green ( normal, soundboard, fireboard, moisture board ). You are looking for density, so if you can get cheap blue/pink/green go for that. Otherwise, just double up on the white.

If you are happy your structure will not get wet, they can also be good for 4 by 2 CLS. Alas, the don't do the larger sizes ( 2 by 6 or 7 ) for flat roofs. You'd need a traditional building supplier for this.

Outside cladding. If you are going cedar, the more sqm you buy the cheaper it gets, see if anyone else is after some. Always use SS (stainless steel nails) pref. off a paslode with a rubber nose.

If you're doing wenge edge ( live edge ) douglas fur, you should try a local saw mill rather than larger suppliers.

Roof coverage, normal three layer felt. Get a GOOD installer, after being burnt ( no pud intended ) we do it ourselfs now. If slate.... I tend to use reclaimed welsh as it looks nice ( I do old houses ). If your a little worried or you are on a low pitch ( you can do down to 14 degs ), just double up on your breathable membrane.

If rubber roofing... Get a specialist in. It's a pain as a lot of suppliers will not sell it to you unless your an 'installer' which is a pain, because you just need common sense.

Where possible. Put more insulation in than you think you need. It also keeps it cool in Summer as well as warm in summer. PIR insulation ( Celotex ) is currently VERY expensive. Keep an eye out on Facebook Marketplace / Ebay / Gumtree for people selling end of project stuff. Selco are not too bad on pricing.

As you will see from the video, offset the joints. I've used a company in Petersfield before for TechSound ( Soundproofing | Soundproofing Products | Sound insulation | Acoustic Insulation | Noise Control | UK ) and they also do acoustic silicone. Actually they will do most of the stuff your after.

Rockwool... Selco stock this and if you have a depot nearby can be a good price. Get the quantities and you should get a reduction. Keep in mind, even though rockwool comes with different sorts of stuff, it's all essentially the same.

Windows // Doors, as you're building new, keep an eye out for second hand / reclaimed. You can easily build the openings to the windows / doors you have onsite. You can get them before needed and save a lot.

Flooring... I presume carpet. As such, you can put PIR on the floor, then 18mm chipboard ( interlocked ) then underlay / carpet. If hard flooring, this can be laid on top of the PIR and save the intermediate layer.

With carpet, just find a carpet whole saler / trade supplier, you'll get a better price than going to a normal carpet supplier. They will also suggest a fitter. I've just had a stairs / landing done with a 80/20 mix for £80 inc. underlay and fitting of 6 door thresholds, inc. labour ex carpet.

Electrical fittings... Screwfix LAP range. It's white, smooth finish with screw covers bloody cheap and readily available. After 12 houses only had one failure and that was my fault !

You will also need a garage consumer unit. If you are running EOP ( Ethernet over Power ) ( internet over power lines ) put a double socket BEFORE you're consumer unit in the garage as a lot of the EOP devices do not like going through two consumer units.

If you can, lay some cat5e ( external spec stuff ) when laying you armoured cable for your office.

Run water down as well, it's not much hassle, but is usefull for later drinks / washing ect.

Paints... Use Johnstons Durable it can be expensive (unless you're mat is the manager), but it's scrubble after two coats, as opposed to emulsion which isn't.

At times I use a company called https://www.tikkurila.co.uk and they do some lovely flat matt products which will reduce reflections. These guys are trade only, but do great products. I've done hiend kitchens with these.

Bass Traps, I've made these before... Well, not so much bass 'traps' but devices to reduce side reflections... pm of easier to call me for info on this.

Lighting... I have to say, I'm a sucker for track lighting, because you don't need to decide positions until later, but sounds like you are being organized so should not need this. But lighting is a whole new and complex topic I thought paints were complicated, I've got books on lighting, very boring stuff....

Ok... I've been called by the wife, better go and do some 'sort of work'. As you can tell, I enjoy construction Which is why I do it for work...

Good luck Paul.

 

[LittleNipper]

The reason Magnet have the cheapest plasterboard is because they use it as a loss leader. Don't go into the kitchen section, go into the trade section. Oddly enough they have now stopped selling plaster ... PIR ( Celotex ect ) is currently expensive as one of the manufacturing facilities in Europe burnt down and they have lost product capacity.

Plaster seems to have gone up a fair amount of late. B&Q can be the cheapest. However, just get a price from a local plasterer. Keep in mind, some plasterers only board skim. Real plasterers do sand/cement board and dental plaster ( coving ) ect. Ask for a two coat sponge finish. No so thin you EVER see the scrimp tape. Ensure they scrim all corners and ceiling joints.Otherwise, as you timber dries ( it will ) and shrink, it will cause cracks.

As a general rule, draw out what you will build and make a list of all the stuff you need. This will allow you to bargain with people a bit better... Fib a bit when you say what your after as you'll get better prices.

Essentially, you are building a loft conversion ( albeit fancy ) but on the floor. If you can find a book about building loft conversions, you will find most of what you need. However, I'm sure they have books on building home offices...

I treated myself to this book :-

RA: The Book - the Recording Architecture Book of Studio Design

Lot's of inspiration from this. It's a lovely book to read / look at and aspire too. You can make a lot of the stuff yourself...

Oh hell, I'm excited for you now ! If you were local I'd come and help out, I've just finished a house and I'm looking for a break from the normal !

 

[imightbewrong]

Wow thanks a lot for all that detail - lots of useful info there. I confess that when you said 'equipment' I thought you were referring to the AV equipment. Hoping my builder will be sorting most of this out - they've been building timber frame buildings for about 50 years, and have done zero-heating properties and a lot of garden rooms - no cinemas/studios though - yet.

Yes planning to run power/ethernet down - not planning to run any EoP - I tried it out and it doesn't get through even one consumer unit in my house - not sure why.

What do you mean by "If you are happy your structure will not get wet" ?

Thanks again for you time.

 

[imightbewrong]

Anyone got any experience of insuring these things? Could easily end up with c. £30K of equipment and furniture, not to mention the building itself.

 

[WeegyAVLover]

no... does that help

 

[LittleNipper]

Insurance wise, most typical house policies actually have quite a high ceiling on them. As long as you itemize the products and send a list ( with values ) to the insurance company, your existing home policy might cover it.

You might find they only want specific lists of items ( single items ) over say, £1k or £2k.

Try your own first before perhaps seaking specialist insurance.

 

[imightbewrong]

Insurance wise, most typical house policies actually have quite a high ceiling on them. As long as you itemize the products and send a list ( with values ) to the insurance company, your existing home policy might cover it.

You might find they only want specific lists of items ( single items ) over say, £1k or £2k.

Try your own first before perhaps seaking specialist insurance.

Do you need to specify they are kept in a separate building typically?

 

[LittleNipper]

Mmm. I’m not sure. Best to ask them.

Equally, as they are.... get locks fitted that ‘they’ suggest, so prob 5 lever mortise and a eurolock. See if they need an alarm ect

 

[mb3195]

Insurance is a problem for outbuildings. I got a quote this week for mine and it was going to increase my premium by around £1500.

Just make sure they are very secure, alarmed, CCTV, etc and you should be ok as most of the stuff in these things aren’t much use to the typical burglar.

Regarding ideas on your build, check out my entire build thread, I did exactly what you’re planning on doing and my equipment list isn’t too different to what you have specced.

Let me know where you’re based, if you’re not too far, feel free to head over for a demo and some build ideas.

 

[PsyVision]

On the insurance note, I asked mine and they said the outbuilding is classed as the house and the same with the contents. Any items up to £10k they didn't need specifically listing.

Possibly AXA, no special policy or mega expensive etc.

EPDM roofs, you can buy them without having an installer, I found it easy to do once I got the weight on the roof as it's very heavy. If you're able to build the building yourself I suspect you could do the roof fine!

Plasterboard and insulation, for me, best prices were on the web direct from manufacturers. I can dig out links or check my build thread!

 

[PsyVision]

Also, not sure if you're having windows or what type of doors, but with mine I find the double glazing is the weakest link, kind of obvious, so id pay for triple if I went again.

 

[imightbewrong]

Holy thread resurrection Batman!

So after a couple of years of dithering about wondering if we are going to move house or not we have decided to stick - hence the garden room is now green-lit. The goal is not to make a dedicated cinema bat-cave - as cool as that would be - but to make a room with three/four uses.

• Cinema / HiFi paradise
• Home office
• 'Den' for four tweens + friends to disappear to - i.e. get rid of them

I'm sure there will be some interesting challenges to balance all of these - e.g. how to make it a 'bright' room but also dark - already thinking of some Somfy wall curtains or something.

Anyway, been messing around in Floorplanner and have doodled up this - a work in progress - this is based around a 3m wide screen:

We have around 7m of length to play with given the width of the garden, leaving about 4.3m if width if we want to avoid the need for building regs.

My main concern/consideration (still) is what to do for the walls/ceiling/floor in terms of audio insulation. The building will be at the bottom of the garden so c. 20m away from our house and our immediate neighbours - there is one neighbour out the back - the building would be approx. 7m from their house although there is a fairly substantial brick outbuilding on the boundary of their property which would be in between.

It is a very quiet area so my main concern is not sound coming in but making sure it is not too obnoxious with sound coming out. @mb3195 if you don't mind - was it Rockwool that you used in your wall space? Did your walls have one cavity filled with this, or anything more elaborate? How did you find the sound insulation?

 

[mb3195]

Yeah Rockwool was all that was used.

Its pretty good, you can hear explosions and so forth from the outside, but it sounds more like thunder coming from a distance.

A car passing on the main road (residential street with speed bumps) is more noticeable that my cinema room though.

Never had any complaints, had it for 4 years now.

 

[turk3y]

looks a great plan, I am building something similar although on a smaller scale (3.5m x 3m). It has the same planed uses and I am trying to work out the floorplan as I will need to start to wire it shortly. Hence snooping through posts

I have the timber structure up however so if you have questions on that I am happy to share my progress

 

[Deleted member 161415]

What a great idea, my 1 penny worth

A 21.9 screen will make if feel more cinema’ish (try to find a way to make it fixed. You can easily use it as a partician for the area that has the desk, you have enough space to put a door one side (into room with desk) and have a recessed cabinet the other side for Amps, dvd, etc. Could even put an “exit” sign above the door (like in the cinema)

An accoustic screen will enable you to put the speakers behind the screen (centre speaker will really deliver this way)

Definitely put a toilet in (no one wants to leave the room in cold / rain to go to main house

7.2.6 (13 Channel Amp)

Your over 30sqm so will need P-Permission, (I think) so make the room 7.5 x 5.2m (internally this gives you approx 4.7m which meanyou can have a 3.5m sofa with 60cm either side (useful for walking past the sofa and the head of the people sat at the end just about far enough away for you side speakers.

Do 2 rows of seating 4 per row, and, instead of a 3rd row, put in a Bar with stools. Most of the time there are 6 of you, the bar with stools will allow an addition 8 people to sit / lean on bar (great when you have large groups round who want to stand / chat at the back (sporting events etc)

3 large bean bags in front of the first row or ideal for up to teenagers to increase capacity.

Electric underfloor heating

Do run two Ethernet cables from you main house to the room

Personal choice Dali Wall Speakers, if you did this and with the other speakers behind the screen it won’t look odd to have dedicated stereo speakers just for music.

Domt worry about building regs, as I assume you would do 100mm King span, overlaid with 25mm anyway

Air con is option is budget will stretch instead of Ufloor heating or a must if those windows are South facing

I’m no good on lighting so can’t really help but, I do like black ceiling with holes in it to create a starlike lighting effect

All topped of with some great movie posters framed.

 

[imightbewrong]

Thanks for for the suggestions - many of things I have pondered in the past

A 21.9 screen will make if feel more cinema’ish (try to find a way to make it fixed.

I'm going for a 16:9 screen which will be used in three sizes - constant height 16:9 and 21:9, and opened fully up for Imax-style presentations

An accoustic screen will enable you to put the speakers behind the screen (centre speaker will really deliver this way)

I have wondered about putting the speakers behind the screen, but I'm leaning towards not doing it and putting the speakers around and below as in my current setup.

Definitely put a toilet in (no one wants to leave the room in cold / rain to go to main house

We're not going for plumbing - the is a loo right at the back of the house (you can see it in the map photo, top left. If people aren't tough enough to cross the garden they can stay in the house

7.2.6 (13 Channel Amp)

Yep

Your over 30sqm so will need P-Permission, (I think) so make the room 7.5 x 5.2m (internally this gives you approx 4.7m which meanyou can have a 3.5m sofa with 60cm either side (useful for walking past the sofa and the head of the people sat at the end just about far enough away for you side speakers.

We are going down the Caravan Act route so planning permissions and building regs aren't really a factor. 7x4 are the current internal dimensions we have which seems to give a good balance of internal size without looking too big in the garden.

Do 2 rows of seating 4 per row, and, instead of a 3rd row, put in a Bar with stools. Most of the time there are 6 of you, the bar with stools will allow an addition 8 people to sit / lean on bar (great when you have large groups round who want to stand / chat at the back (sporting events etc)

Seating is the thing I am looking at now - currently thinking about one or two rows of sofas plus bean bags. And some outside seating for when we open up the bi-folds and go on the decking.

Electric underfloor heating

Cooling will be the problem rather than heating I think - there will be quite a bit of kit in there - my current office is heated purely by a Crypto miner

Do run two Ethernet cables from you main house to the room

Yep

Personal choice Dali Wall Speakers, if you did this and with the other speakers behind the screen it won’t look odd to have dedicated stereo speakers just for music.

I need to do some research on the surround speakers - not sure how the different types compare between in wall, flat panel, the multi-directional box ones.

Domt worry about building regs, as I assume you would do 100mm King span, overlaid with 25mm anyway

We are using Rockwool for insulation, as Kingspan has pretty much zero acoustic properties.

Air con is option is budget will stretch instead of Ufloor heating or a must if those windows are South facing

The windows are North facing but I think we will still go with air con.