Thanks for the image. That's helpful.
I would agree with not going s/h on the projector. When you're buying your first pj, unless you know what to look for in a used machine then you really want to stick with something new, particularly in this price sector. There's not enough difference between used and new prices to take the plunge blindly, so don't risk it unless you're paying an expert to source something good on your behalf.
The other thing is that you may be likely to upgrade relatively quickly, so don't spend too much when this is just one part of the total budget.
Other rookie mistakes are cheap pull-down or cheap electric screens. They're crap. Because all the parts are bottom-Dollar-cost then the result is a light-weight screen where the surface has ripples and the edges curl. You'll see these ripples as your eye tracks action moving across the screen.
A screen does make a difference. You can spend a lot of time and a chunk of cash prep'ing bits of board and painting them with various concoctions of domestic paint to make a DIY screen. It'll be better than projecting on to the wall, but not so much better that it's worth all the hassle. A better option is a fixed frame screen.
If you haven't come across this idea before, it's what proper commercial cinemas use, but the domestic version is on a much smaller scale. This is a bit like a very large picture frame with a vinyl canvas surface stretched across it. The edge of the frame will have a light absorbing velvet-effect frame.
The thing with frame screens is that they're permanently on display. This doesn't suit everyone, but for someone with a dedicated room and on a tight budget they're a Godsend. All the problems of cheap roll-down screens go away. The surface lies perfectly flat, and stays that way. The other advantage is that you won't need to buy something better for a very long time. That is by far the best deal you'll get. Buying twice because you bought cheap the first time round makes this hobby expensive, so don't do it. Spend what you need to now to get something decent that will last a good while.
At the top end of the market a fixed frame screen can cost several times your entire room budget. But at the entry-level you can get something very useable brand new for £150 to £180. There is a catch though. You're going to trade off some time in assembly when you're spending so little. That's because the frames for these things are mass-produced and not test assembled before shipping. That's part of why they're cheap. This means you may need to drill the frame to get the fixings and alignment correct before the material goes on.
With a higher-end frame screen at £500+, I can unpack, assemble and hang it in around an hour. With a budget frame screen I would allow anything up to a half a day. There's nothing to say it will take half a day, but I'd still set aside that amount of time and take anything less as a win.
Have a look on Amazon at the Celexon screens. Be aware that the Chinese sellers can be a bit sketchy with their measurements. They don't understand inches, so double check everything before ordering. This is important for the projection distance calculations.
Your sound system choice is bad. Sorry to be blunt, but there's no point in beating around the bush here. There are so many reasons why. Here are the main ones..
* No external HDMI inputs, therefore no way to connect any HDMI audio source so no HD audio - What's the point in a home cinema room is the sound is compromised?
* No external video inputs. How are you going to connect the consoles and BD player and any other video sources without either running a bunch of extra cable to the projector or buying some kind of video switch?
* Only 1 optical input - this is your only way to get some form of digital audio in to the device, but you have more than one source to connect that way, so you're going to end up buying an £80 remote controlled optical switch and make life far more complicated. Leave it out.
* Poor sound quality - It may impress for the first hour or so if this is your first taste of surround sound, but after a while you'll tire of the harsh edge to the upper frequencies, and get fed up with the lack of vocal clarity, and become annoyed with the sub that fails to be either truly deep or articulate. It just bangs around like a disgruntled teenager.
* No upgradeability - Once you start to get fed up with the sound (and the connectivity, and lack of sound processing features), you'll start searching for ways to swap out bits. That's when you'll come to realise that these all-in-one kits are a technical desert island. The speakers aren't any use with a standalone amp, and the head unit won't work properly with aftermarket speakers. The whole thing is a financial cul-de-sac.
* Poor long term reliability - They fail. Simple as that. Mostly it's the BD player that goes first on these type of systems. Once that happens, you have to chuck the whole lot away because there is no service support for them.
* No residual value in the used market - Says it all really.
The way to do sound and deal with connectivity and audio processing and upgradeability is to go for an AV receiver and separate speakers. Here's where you should buy second-hand.
An AV receiver is the connection hub of your system. Whether the source has HDMI, or optical/coax, or stereo RCA phono plugs, it all gets connected to the amp. (No, we don't run sound up to the projector and then back down again. That's messy, its complicated, and also limits the audio processing abilities.) The receiver splits the sound from the picture (which it sends to the projector), then deals with whatever audio format is required.
Your BD disc will have lossless Dolby TrueHD and DTS-Master Audio as well as lossy core DD and DTS versions of the same for backwards compatibility. The Freeview (or Freesat) box will carry Dolby Digital for the HD channels and Dolby Surround (DS) for the Standard Definition channels. DS is decoded using Dolby ProLogic II which is something that a lot of all-in-one kits lack. Games can carry any audio format, but very few make use of HD audio. The Wii has stereo RCA phono out for audio. That's as good as it gets, but there is an optional Component video cable for better picture quality. That's worth having a look at if you're going to be playing on a projection screen, and, if you get the right AV receiver, there are some that will convert Component video to HDMI which simplifies your video connections (another reason to avoid the all-in-one kits).
Once you have your AV receiver you'll need some speakers. This can be a bit more complex for a novice; knowing what to buy and what to avoid. The basics of a 5.1 speaker package are the centre and front L&R speakers should be from the same manufacturer, and ideally from the same range unless it's known for sure that the tonal characteristics match. What we don't do is mix a centre from one brand with front L&R from another.
The surround speakers in a 5.1 layout go on the side walls not the rear. If you go 7.1 then that;'s when speakers go on the back wall. It's less important to match surrounds to the front three, but you'd still try to be aware of mixing something very bright sounding with something that lacks treble.
The sub can be from any good brand. It has its own amplifier built-in but it only handles the bass, so all it requires is a line-level bass signal from the AV receiver. This isn't the same as a speaker-level signal. In general, the bigger the sub the deeper it will go, but there are some exceptions both ways. Cheap subs are cheap for a reason, so a big cheap sub probably won't go as deep or sound as tight as a smaller but better quality sub from another brand. There's no substitute here for product knowledge and experience.
Ancillaries: You'll need a projector bracket, and possibly brackets or stands for some or all of the 5 surround speakers.
Don't skimp on cheap speaker cable. It doesn't have to be expensive, but buy a basic good quality all-copper 1.5mm diameter cable based on something with 30 to 60 copper strands. Avoid anything involving aluminium or steel or quoting CCA or CCS in the title. Copper Coated Aluminium or steel is rubbish for home audio. You should be able to hit the mark for around £1.20/m.
Similarly, buy a decent sub cable. This might seem like an extravagance to spend £30-£40 on a 5m bit of wire, but when you're doing your nut wondering why there's a hum on your sub then you'll know why you should have spent the right money in the first place.
Buy banana plugs for the amp end of the system. Trust me, if you've ever tried to wire up 10 closely spaced screw-down terminals with multi-strand copper cable round the back of an amp with limited space and a lack of light, and hoping to God that there aren't wires bridging other terminals causing potentially disastrous shorts, then you'll know exactly why banana plugs make life much easier for an amp hook-up.
In summary, stick with the lower cost Optoma. With £1000 budget and a lot to buy - now knowing the reasons why you need to spend more on the amp and speakers - otherwise, unless you can throw some more money at the project, you'll end up cutting too many corners buying a better projector that it compromises the rest of the system. Keep things in balance.