From the Forums – DIY Cellar Home Cinema Project

What a great use of space

by Mark Hodgkinson Apr 30, 2017 at 7:18 AM


  • Our member bigmacx has been on AVForums since 2001 and, inevitably, has picked up a few tips along the way.
    Like many of us, bigmacx has been ‘messing around’ with Home Cinema for many years and has gone through a number of iterations involving various TVs, projectors, home-made screens, DIY speakers etc. and always hoped that one day he’d have the opportunity to have a dedicated room.

    Around 8 years ago Mr and Mrs bigmacx bought a Victorian town house with a (typically damp) basement which was effectively split in two. One half got used for storage and the other got used as a workshop while the house was being renovated. Six years and 1 and ½ children (another little bicmacx was on the way) later the cellar was barely being used use so the decision was made to turn it into a living space; even better Mrs bigmac gave permission to it turn into a home cinema / recreation room. The only issue being the deadline imposed by the impending baby making its entrance.

    This is what the room looked like before work began:



    The Plan



    Starting aims were:

    •Acoustically transparent screen with gear hidden away
    •Soundproofed as much as possible.
    •Completely light controlled
    •Usable during the day and night (Projector and TV?).
    •Should be a reasonable environment to relax in when not in black-out movie mode (i.e. not a complete ‘bat cave’)
    •Room for the bike and turbo trainer so it can also be used for winter training
    •Built in storage for all media
    Over the years bigmacx has been increasingly unimpressed with the ‘value’ offered by higher-end Home Cinema – especially on the audio side. So whilst he was happy to spend extra on the room itself (if it made a quantifiable improvement) he made the deliberate decision to try and do the equipment side on a budget – and hoped that the challenge might actually make the whole thing a bit more fun. What that came down to was:
    •Re-use existing gear
    •Pro-audio gear over consumer where possible (amps, speakers, cables etc.)
    •2nd hand gear where it made sense.
    •DIY Subs (more of a requirement given where they were going to be located)
    •DIY screen - acoustically transparent screens are expensive!

    So – with a rough plan in my head he started getting busy in SketchUp to see if the dimensions made it a viable project and came up with the following plan:

    Trying To Get it Built

    Convinced that it all looked feasible bigmacx started looking for a suitable building firm to do the work. Having dealt with multiple builders before he really wanted to get the whole job done by a single firm. Previous experience of managing multiple builders and their schedules (and subsequent bitching about each other’s work) made him want to avoid that particular hassle this time round. Given that structural work, damp-proofing, electrical, plumbing, decorating was required, he thought the easiest thing would be to contact firms specialising in cellar conversions. That didn’t go terribly well – despite getting three firms to quote not one wanted to take responsibility for the whole job.

    Wanting to make some progress it was decided that a structural engineer would be brought in, since he knew he’d need the calculations for the removal of the supporting wall then the subsequent sign off from building control - and that could take some time. Fortunately, the structural engineer chosen happened to have worked with a building firm that he was happy to recommend. They responded swiftly and after a few discussions they decided to proceed.
    The structural engineer recommended a box frame and digging out about 18 inches of floor to lay a new concrete base. Being an old Victorian house there was no real foundation to speak of so this didn’t take too long. Although it did take 3 skips to cart away all the material.

    Damp Proofing

    Initially bigmacx assumed the builders would go with the typical solution of membrane + drainage channels + sump. The builders' thought that was overkill given the amount of water ingress it was seeing and proposed a simpler solution based around a cement based tanking and a DPM. Although the reduction in cost was attractive, they were unsure as to whether this was a good place to save money. Ultimately he decided to go with the builders’ recommendations given that:
    a) Having done cellar conversions before - they were the experts.
    b) The work came with a 20 year guarantee.

    Time will tell whether this was the right choice (so far so good though).

    Cabling

    Prior to the plasterboard and insulation going up bigmacx realised he needed to work out all the cabling requirements. He was pretty sure that he was going to go for active speakers and having suffered from interference from long phono runs to a sub before he had planned to use balanced/XLR connections. Rather than install separate power sockets for each location bigmacx decided to install IEC cables and run them back to where the equipment rack was to be located. This was with the intention to be able to switch all kit on and off from a central location.
    The eventual run-list looked like this.

    Front wall
    3 x XLR runs for left, right and centre speakers
    5 x IEC power cables for speakers, subwoofer and TV
    1 x HDMI for TV
    1 x Coax for TV
    1 x Cat 6 for TV
    2 x Speaker cable for sub (in case sub amp is with rest of kit)

    Back Wall
    4 x XLR for surround speakers
    5 x IEC power cables for projector and surround speakers
    1 x HDMI for projector
    Side Wall (location of rest of kit).
    3 x Cat 6.

    Sound Proofing

    Although not critical bigmacx was keen to soundproof the room as much as possible, given it was directly below the living room, and took a fairly standard approach of Rockwool insulation (100mm RW5) and a double layer of acoustic plasterboard with a Green Glue filling on all walls and ceiling.

    Plaster-boarding & Boxing-in of Utilities

    Like the say, a picture is worth a thousand words…
    And here’s another thousand...

    The Fun Part

    It was at this part that the builders departed and bigmacx could get down to the business of actually doing the Home Cinema end of things. For the next couple of months many a late night and weekend were spent down in the cellar.

    The tasks were:
    •Build shelving to hold all CDs, DVDs, Blu-Rays, Computer games etc currently dotted around the house
    •Build screen wall to hold TV, speakers, projector screen and subwoofer
    •Fit flooring, skirting and coving.

    This is the initial SketchUp model for the screen wall. The three boxes below represent two different sizes of speakers he was considering (he eventually went for the smaller size).
    Due to either a rash of enthusiasm or flat out tiredness bigmacx forgot to take many photos during this time so the project skips ahead a bit haphazardly form hereon in but we’ll forgive him!

    This is the media shelving – built from redwood, prior to staining..
    And this is the boxing for the screen and speakers.

    The Screen

    Having done some research - on AVForums, of course - bigmacx wanted an acoustically transparent screen and wanted to approach this from a DIY angle.

    Various people appeared to have been having good results with a material called ‘Milliskin Spandex’ and given its relative low cost, and the desire to do this on a budget, it was worth a try before exploring the more expensive options of dedicated screen material. bigmacx couldn’t source a domestic supplier of that particular brand but did manage to find a material with essentially identical properties (80% nylon, 20% spandex/lycra, ~200g/sm) at £67 for a 10m role that he thought was worth a punt.

    Given that he wasn’t sure how well the material would work he also wanted a way to be able to easily replace the screen material at a later point without having to dismantle the frame. After a bit of digging around a few threads here, bigmacx found something called ClothGrip extrusion which seemed like it would serve this purpose.
    Screen frame added. Note hinges at top to allow screen to be lifted.
    Clothgrip extrusion attached to frame – he had no idea how much trouble he was in for with this stuff.

    Subwoofer(s)

    It was decided early on that the budget and requirement for the subs to sit within the screen wall meant that DIY was going to be the best option. The fact that subs would be hidden away meant the cabinets only had to be functional – not pretty - which made manufacture pretty straightforward.

    After a quick search on ebay he managed to find some Peerless XLS 10 drivers for £68 each. Throwing four of them into a couple of sealed boxes with 80L per diver on WinISD showed they should do a fairly decent job of filling out the lower end.
    Max SPL plot. 105db at 20hz should be more than enough headroom.

    Flooring, Skirting and Coving.

    Originally bigmacx wanted to go with engineered wood flooring but a timely chat with the better half and a reminder that wood and cellars, especially ones that stand some risk of flooding may not be the best mix. After a bit of searching he settled on Schreiber Appalachian Hickory which seemed to have good reviews and the colour he was after. It’s also quite fun to install., apparently as it’s a bit like doing a giant jig-saw, except you get to use power tools when a piece doesn’t fit!

    Audio

    As earlier stated - over the years bigmacx has become of the opinion that a lot of hi-fi gear doesn’t appear to offer too much value for money, especially when you compare it to what you money gets you in the pro-audio world. He’d also always fancied trying active speakers and after a bit of research narrowed it down to a couple of options: the Behringer B3031a and the Behringer 215D. He’d been hearing good things about the 215XL (non-active version of the 215D) in home cinema applications but in the end decided to go for the B3031a since:

    a) Its size made it slightly easier to work with inside the screen frame
    b) He’d always wanted to try something with a ribbon tweeter
    c) Just cos.

    A pair of M&K SS150 tripoles that he’d had forever would be taking care of rear duties.

    For the subwoofer side a Behringer iNuke3000DSP was the easy choice – cheap, plenty of power and built in EQ. It is very noisy however so the stock fan was replaced with a ARCTIC F8 PWM, a fan controller and a few heat sinks on the output devices to compensate for the slower fan speed.

    Finishing the Screen

    He thought this would be the easy part. He was wrong.
    Oh dear lord was this tough, says bicmacx, he thought he was going to be able to push the material into the Clothgrip using a credit card or something similar but ended up using a two handled paint scraper and a lot of body weight – and that was just the first layer of material! Good job he bought 10m as a significant amount ended up being scrapped whilst he worked out how not to tear it. To anyone else considering this route bigmacx would strongly suggest buying the dedicated tool they sell for this purpose!!

    Projector (+ Disaster)

    From having owned a number of projectors previously bigmacx knew that he preferred the look of LCD/LCOS over DLP so had been keeping an eye out on ebay and the AVF classifieds for a bargain. When a JVC X30 came up for £600 on ebay he put in a speculative bid and won it. It arrived in pristine condition and threw a great picture, although the bulb was getting a bit long in the tooth. Official JVC bulbs were £260 and paying out almost half the cost of the projector for a new bulb was not an attractive option. However, having done a bit of research he knew that some people had been seeing blown ballast boards on the JVC DLA line and there was the suspicion that buying cheap bulbs was exacerbating the problem. After a bit more research he found a Philips bulb that was more expensive than the budget offerings but well regarded – bright as the original JVC bulbs and people had been running them for several hundred hours with no problems. Bigmacx odered one from the states for £60, fitted in and all was good – brighter picture and no apparent issues

    Several months later, with the screen now in place it was time unpack the projector and see how everything looked. Except – no picture, just a blinking red light. Oh no!

    He put the old bulb back in and still no joy so was faced with a bit of a quandary:

    a) Send it off to be repaired; except the likely cost would be the same as what he’d already spent on the projector.
    b) Write it off and buy a new projector.
    c) Buy a new ballast board and attempt a speculative fix himself – although there was no guarantee that would work OR that he actually had the technical chops to do so.

    Brave soul he is, bigmacx decided to roll the dice and go with c) so a new ballast board was duly ordered from the states. Several days later it arrived and he began dismantling the projector to fit it.

    All Done

    So, after several months of extremely hard work, the job was finally done and we think you’ll agree it’s an outstanding job:
    Due to now having two young children this is a view bigmacx rarely gets to enjoy but the alcohol has come in useful however.
    We salute you sir!

    Kit List:

    · JVC X30 Projector
    · Panasonic 50" Plasma
    · Denon AVR-X3200W
    · RDL FP-UBC6 6-Channel Unbalanced to Balanced Audio Converter
    · 3 x Behringer 3031A Speakers
    · 4 x Peerless XLS 10 subwoofers.
    · 2 x M&K SS150 Tripole surrounds
    · Behringer NU3000DSP INuke
    · Humax DTR-T2100
    · Google Nexus TV
    · Media PC
    · XBOX 360
    · Sony BDP-S350 Blu-ray player
    · Belkin Pure AV Power Console PF240
    · ESYNiC IR Repeater
    · Energenie ENER017 Master/Slave Energy Saving Block

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