Build your own Stealth Cinema: Part I

Building a home cinema is the ultimate goal for any hardcore AV enthusiast. While anyone can covertly pile more and more gear into the living room to feed their obsession, a dedicated media room remains the real prize. HCC often features desirable custom cinemas from both ambitious hobbyists and pro-installers, but faced with the challenge, could we produce a room comparable to a seasoned CI professional or passionate fan?

HCC editor Steve May has seen hundreds of custom installs over the years and is a bona fide certified THX installer (well, he attended a course back in the day) but, while he can talk the talk about advanced installations, can he walk the walk?
His challenge was to turn an ordinary (1930s-built) living room into a knockout hi-def home cinema. In true Gadget Show-style, his challenge came with rules: he had to design, specify and build the job without help from CEDIA members (although he could call on a few mates). Would the job be a walk in the park or a stress-strewn nightmare? Would it come in under-budget or get horribly out of control? Read on…

'Over the years I've had many AV systems, all cobbled together from various bits of kit, and they have all essentially taken over the family living room. The challenge here was to create a dedicated media space, albeit one on a realistically modest budget. Coming to the project I had a clear aim, I wanted to make a ‘stealth’ cinema, free of visible speakers, that still delivered a superior level of performance. I wanted a bigscreen TV, in-wall 7.2 speaker package, electric projection screen and PJ, plus sundry sources from Sky HD to Blu-ray. I knew it could be done (I’ve seen and heard enough), but frankly what I know about DIY you could write on the side of an envelope. This wasn’t going to be easy...' - Steve May, Editor

1 The room chosen for the home cinema makeover began life as a cosy living room with large fireplace and bay windows. The first job was to remove the fireplace and brick up the resulting hole. The bay itself would provide the seating area – it faces the largest wall-space, which would hold the screens.
The alcoves either side of the firebreast were then battened out, to provide a flush wall. The space in the alcoves would provide the ideal location to locate two in-wall subwoofers, one either side (employing two subwoofers significantly increases the sound pressure level in the room and reduces localisation of bass effects).

2 A false ceiling was then created. This would allow all the AV and loudspeaker cables to be strung aross the room, as well as let lighting and a trapdoor projection screen to be recessed, along with the surround speakers – all four of them. Lowering the roof would also provide the ideal opportunity to change the angle of the ceiling. By engineering a subtle slope, so that one end of the room is lower than the other, thereby creating non-parallel walls, you can reduce flutter echoes in the mid-to high frequencies caused by sounds as they ricochet around.
However, a sweeter top-end may not be a good enough reason to deliberately build a wonky ceiling. In the first of what were to be several compromises to preserve domestic harmony, I settled on a conventional design.

3 There was little doubt in my mind which subwoofer brand to go for. Velodyne’s Signature 1812 remains the definitive high-end sub in my mind, and while I couldn’t contemplate any such beast in this install I wanted the brand’s trademark tuneful LFE. So I opted for the SC-IW and SC-BB backbox (pictured), from Velodyne’s SubContractor series. Looking quite unlike a traditional sub, the SC-1W is a slim-line two-box solution which fires vertically thanks to a T-shaped driver design.
The sub ports out into the room, via either a 14in grille or much smaller 5in letterbox. My battens formed a perfect frame for the two enclosures. The top-enclosure back-box sits flush with the wood work; the lower driver module sits proud, meaning that plasterboard is cut around it before the grille is attached. A passive design, both subs would be run from a single outboard amplifier, the Velodyne SC-1250, which has 1250W of muscle on tap. With so much power available, it was essential that the new wall was a rigid as possible

4 Some of the loudspeaker cabling to the two subs and the coaxial cable from a Sky dish was routed through a hole that dissected the old firebreast. The cabling was snuggled inside a tube of pipe lagging, which then sat inside plastic trunking.
This was to prevent the cables themselves moving and rattling once the wall was up, a distinct possibility given the in-bedded nature of the subs. Whenever cabling is run behind walls, it’s well worth bedding it down to prevent rattles and noise through movement. The last thing you want is to be forced to neuter your amplification for fear of cable clatter spoiling the fun.

5 The main ‘viewing wall’ was duly battened outwards. The idea was to create a frame for a wall-mounted screen that would also accommodate the in-wall left/centre/right speakers. Definitive Technology was my brand of choice. I’ve long hankered for Def Techs, having enjoyed countless top-notch demonstrations. The brand’s Reference UIW RLS 11 in-walls would provide the front soundstage. They offer rich, articulate audio comparable to prestige floorstanders. With pure aluminium dome tweeters and high-performance drivers, they are just the job for stereo and multichannel applications.

6 With the main batten work up, it was time for the lighting rig to go in. The lighting system itself was from Niko, the leading smart-lighting operation from Belgium. Handling its install was RajVar Technologies, specialists in advanced lighting control systems and installations. Normally RajVar handle large multiroom installs, so this single media room was small potatoes. The Niko Nikobus lighting system is controlled via Cat 5, running to an exterior control board which was to be located in the nearby garage. So it seemed like a good idea to extend the home’s wired network into the room simultaneously, and run enough network cabling to create a boot room for a server.

7 There is no shortage of options when it comes to cabling. There are as many cheap no-brand solutions as there are ultra high-end wallet-breaking alternatives. I trod a middle ground, opting for a range of cables from market-leader Ixos, a brand that promises affordable quality.
The Def Tech speakers were wired with Ixos’ XHS523 Parallel Geometry low-resistance silver speaker cable. I picked up a drum of 100m which was to prove ample.
A full complement of IXOS interconnects were then laced across the ceiling beams to link the planned projector with the electronics which would be positioned under the screen – including a pair of HDMI leads, VGA, S-video, component, composite and a 3.5mm lead to provide a 12V trigger. The HDMI cable run measured 15m. All were checked for signal integrity before being committed to the install. It’s vital you do this, because finding you have a duff lead after the ceiling’s been plastered is not a good thing.

8 Even though the ceiling height had been lowered, it quickly became apparent that the space was not sufficient for the projection screen housing. My chosen screen was from Screen Research range, an acoustically-transparent THX-certified model.
Having acoustic transparency was vital for the screen as it would descend in-front of the Def Tech speakers.
There are two types of AT screen available, those that are micro-perforated and those that are woven. The former can’t effectively be used with modern fixed-pixel projectors because the pixel grid of the projector tends to create a ‘beat’ pattern with the holes in the screen. All Screen Research AT screens are woven.
With the gap measured out, Builder Dave (no job to big) then set about hacking back the joists so we could fit the screen casing. The case itself would be screwed directly into the ceiling joists.

9 RajVar's Rajesh Varsani ran Ethernet cable to the bay window, adding extra network points to help futureproof the room. You can never have enough networking points

10 It was never my intention to soundproof this cinema room. But that shouldn’t preclude the sensible use of noise control practices. The first sensible tweak is to use acoustic-grade plasterboard. Typically only a few quid more expensive than regular plasterboard, it will improve thermal control and enhance structural rigidity – important as I was building two subwoofers into the wall. I used 12.5mm Gyproc SoundBloc, throughout. Actually, I used two layers of Gyproc SoundBloc, with a filling of Green Glue. Green Glue? What the heck’s that

11 The US makers of Green Glue suggests that an application raises the energy dissipation of the material it’s spread upon by around 100 per cent. It also reduces structural resonance; this is useful when in-wall speakers are rigidly fixed to both wooden battens and the boards which make up the wood.
It would be wrong to think of Green Glue as some kind of miracle sound-proofing gunk, it’s not. But there seems plenty of evidence that it can, at the very least, diminish some of the energy in the cinema room structure itself.

12 Green Glue is not an adhesive. The sweet-smelling gunk is actually a visco-elastic damping material designed to help attenuate sound waves as they travel through material like plasterboard, shortening the decay distance of all frequencies to lesser or greater effect.
It’s very easy to apply – simply swirl-pattern it generously onto the inside of the second ‘board and then screw it to the first. HCC’s own Matt Moule is an enthusiastic advocate of the GG so it seemed prudent to give it go

13 I could have taken additional sound control measures, such as filling the space between the original ceiling and new lowered ceiling with damping material, but the impact of this would have been minimal. Once the acoustic plasterboard was up, complete with Green Glue filling, the room was beginning to take shape. Pictured above is the video wall; you can see the recessed area where the plasma TV will be fitted. Note the channel trunking to carry all the video leads down to the recessed electrical power bay; there’s also a power feed to backlight the TV, although at this stage I’m not sure how this will be accomplished...

In part 2: The cinema room begins to take shape, although not without some strain. Thrill as our team try and fix an over-sized screen into the ceiling, power up the Niko lights, wrestle with plasma mounts and take a visit to DFS

COMPANY CHECKLIST
HCC’s D.I.Y. home cinema used the following kit and service providers...

Velodyne
SC-IW SubContractor in-wall subwoofer, £815 SC-BB backbox, £145 Velodyne SC-1250 power amp, £850
www.red-line.co.uk
Tel: 0131 555 3922

Definitive Technology
Reference Series UIW RLS 11 L/C/R speakers, £650 per speaker Reference series UIW RSS 11 surround speakers, £599 per speaker
www.pulsemarketing.org
Tel: 01279 718 884

Screen Research
THX Acoustic Transparent in-ceiling trapdoor screen (product code MS-IT-110-178-2W-B) inc motor controller, £6,315
www.pulsemarketing.org
Tel: 01279 718 884

Niko Home Automation & Lighting Systems
Niko Lights are a favourite with European high-end installations. Niko Lighting can also be used with home automation products.
www.usd.uk.com
Tel: 01525 877707

RajVar Technologies
Smart lighting and home automation system integrators
www.rajvar.com
Tel: 020 8206 0979

Future Automation
PF-65 Plasma mount, £200
www.futureautomation.co.uk
Tel: 01438 833577

Goelst
G-Rail 6200, £price on application depending on requirements. Can be integrated with the Niko Smart Lighting system
www.goelst.nl
Tel: 01423 873002

Daikin air conditioning
FTXG-E air conditioner plus external unit, inc. installation, £2,500 approx
www.daikin.co.uk
Tel: 0845 6419000
Cool Connections
Tel: 01708 724165

Green Glue
Case of 12 857ml tubes, £98
www.greenglue.co.uk
tel: 01303 230944

Ixos Cables
www.ixos.co.uk
tel: 01844 219 000

And last but not least..
Builder Dave Ryall
Tel: 07957 488 002