Life expectancy

Speakers can last for a very long time. There are a lot of variables in what makes a speaker last. Speakers lasting a decade is not out of the question. I have had speakers for twenty years that where as good as new. The foam surrounds never even cracked. Making speakers last a long time also means that you don't abuse them by blowing them or playing them beyond their limits.

One of the biggest problems I see in your case is the size of your room. It's really large. This makes it easy to over work speakers. A room 40'x40' is really to large to try and build a theater in and expect to reach louder SPL levels. Especially in the bass department.

40x40'! Are you sure? That's a HUGE space, bigger than many houses. The speakers should remain usable for most of your lifetime especially if they're in a temp controlled room.

I'm using some low end B&Ws I bought in 93. I live in a warm, high humidity environment and the speakers still work great. Same for the $200 Audiosource sub I bought in 99.

I wouldn't worry about the longevity of any speakers you're looking at.

That room is indeed huge. My entire urban house isn't that big, and my custom-designed listening room at my desert house is very large but less than half that size.

The first thing you should know is that 99% of the HT receivers on the market do not have the power one would need for that room to set up HT. You need 200 watts RMS for each channel with ALL FIVE channels driven.

A preamp/processor unit such as the Marantz AV7005 would be essential IMO. It has no power amplifiers of its own, which allows the installation of individual mono power amplifiers at each speaker location and to run balanced cables long distances to them as needed from the AV7005 or similar unit with balanced outputs on all channels.

I am not sure what kind of money gives you sticker shock, but I don't think you can realistically set up any home theater in that room for any less than $10,000. It might easily require twice or 3 times that much money.

My 2-channel stereo system in a room half that size at my desert house has about $25,000 worth of equipment in it, so one could easily spend $40,000 on good-quality equipment for a 5-channel system in a 1600 sq. ft. room.

My advice would be to set up a viewing and listening area in one part of the room (about 15 feet wide and 20 feet deep) and in it set up a 73" Mitsubishi HDTV (or similar unit) with two very good large speakers and two subwoofers and a top-quality preamp and power amplifier. You will have a good-quality sound setup for movies in that area and the acoustical problems will be far less than trying to do multi-channel HT in such a large space. The acoustical problems could be immensely difficult for 5.1.

One good way to do this is to set off the viewing area to some extent with free-standing or ceiling-suspended acoustical panels. If you could effectively create a smaller room with acoustical-panel "walls" then you would also have a much easier time doing 5.1 if or when.

Another possible setup is to put the TV/TV stand/equipment across a corner of the room and have the speakers near the walls on either side.

One wild card in all of this is how many people you intend to have viewing at any one time. I assume you are talking about 10 or less, rather than 40 or 60 people. Two different problems entirely.

I would recommend that you start by getting the Mitsubishi WD-73838 3D DLP HDTV (there is also an 82" model), which Amazon has for about $1700 now. It has an excellent picture, IMO as good as the very best LED or plasma sets. I have the 60" version and am very happy with it. A good base unit with two shelves for amps, players and other boxes is the Tech-Craft BCE 73 stand (or Tech-Craft BCE 82 for the 82"). Mitsubishi also has its own stand for the 73" which is on Amazon.

Speakers usually fail from being overdriven and overheated; good speakers should last at least 20 years in most environments.

Like has been said, that's a large room and in my opinion, if you want to do it right, you're going to have an expensive project on your hands.

Then again, you didn't state a budget and frankly, anyone who's got a 40x40 room in their house.... probably has reasonable means behind their wallet. Now it becomes a matter of simply doing it right.

Some random thoughts.... (presuming the stated facts are correct that it's 40x40 feet)

1. I'd shy away from anything that is HTIB. This is presuming that you want something "real" sounding, as in, on the scale of life.

2. I'd look at high sensativity which means, horns. (fret not, there are some excellent sounding horns out there)

3. You can buy something like used LaScalas and some subs and have a killer system for what might be a modest price.

4. You can mix some Lascalas with Klipschorns (which would need to go into the corners which might be a problem) for killer sound.

5. You could really throw some balls to the wall and do what I suggest.... look at some of the commercial offerings of Klipsch. Scan Ebay for some MWM bass bins (they are HUGE....look at my avatar on the bottom)

I bought those two single cabinets delivered for under $500 (which included delivery from Florida to Tennessee) I actually paid $250 on ebay for them.

I got lucky.

Still.... keep in mind "right tool for the job" and with a life size room, you are going to need life size answers.

Where are you located geographically and what's your budget?

Oops, thought I had an avatar here. I'll see if I can post the picture.

Ok, I couldn't find the exact picture I described above....but....here's the other version of the bottom.

The pictured bottom is 8 (yes about eight) feet wide. It's a monster. The one in the picture is a double bin.

I bought the SAME thing however, it was split and was two single height bins. Makes them much easier to handle.

Anyways... if I were you, I'd be looking for some of these. Probably no more than 5 (5 doubles if possible but for indoors, 5 singles would probably still be better than anything you've ever heard)

and then work on the upper horns.

In an air conditioned home, speakers can last decades. If you have to put them in a garage or other storage, they can last a few months or worse if housed under poor climate and humidity control.