The issue with hard drives is that they tend to fail even on ideal conditions and even when powered down. Yes I’ve lost very important data to a powered down hard drive.
While it’s possible to recover information on a hard drive as long as the plates themselves aren’t damaged, that requires very expensive specialised tools and skills. Which probably wouldn’t be available in a scenario where the information on the drive would be of any value.
DVD-R (and probably consequentially Blu-Rays) aren’t any better in my experience, I’ve lost more data to DVD-R than to hard drives actually. Even when stored in low light conditions they tend to just stop reading.
However optical media has one big advantage here, is that the discs themselves are cheap, so instead of having all your digital eggs in the same basket, you spread them over several discs and while some information may be lost, others may survive.
Now, here’s an interesting thought, with digital data, the data either reads or doesn’t read, the so called digital cliff, may become partially corrupted and other parts still read, but after the corruption gets past a certain threshold all information is lost.
With analogue equipment even after severe signal degradation the contents while very deteriorated may still be perceptible, forwardermore an analogue signal is much easier to decode in the event that you need to restart civilisation building tech from scratch and don’t have access to the very very specific specifications of something like the audio codec or the filesystem.
You can probably hack a rudimentary cassette player together from very simple components, all you need is a tape head (a coil), a motor (a coil and a magnet), and an amplifier (a transistor or vaccum tube). (I’m probably oversimplifying here).
Overall I think the most important thing is having redundancy, or if redundancy isn’t possible at least don’t have all eggs in the same basket, instead of having everything in a single 8TB HDD, to try spread them into smaller 512GB ones, or DVDs or flash drives or all of the above. And don’t store them all in the same location, if an area gets flooded or someone builds a building on top, you’re only losing a small part of the information.
If you are speaking about soundproofing I’m assuming you live in an apartment and have neighbours, I will be making my recommendations based in that assumption.
Also, note that I value audio quality more than video, so if I have a limited budget to setup a home cinema most of it will go to the audio.
For home cinema surround systems are usually the standard, however in my personal and subjective opinion surround adds much to the cost without really proving much value to the experience.
Cheap surround systems like those trendy soundbars will sound like shit comparable to a stereo system for the same price. Yes, they come with a subwoofer so they have bass and provide that wow factor, but you may notice it to be unbalanced the middle or upper frequencies to lack clarity.
If you have a small room and plan on watching films just yourself (and maybe an occasional friend)I recommend a setup similar to mine, a small LCD TV (32" or a bit bigger) and a pair of 8" studio monitors.
From my understanding cheap projectors have quite a substandard image quality and brightness, I understand that you prefer a projector for easier transport, but a small TV is also easy to carry it, you can literally carry it in the backsit of a small car. And will look much better than a cheap projector.
So with your given budget you can get a quality TV for about 500 dollars and a quality pair of near field speakers for another 500 dollars.
This is the perfect setup for a single person intimate setup, however fails short when you put multiple people in the room.
However if you have a big room with many people on it then you will need to compromise on quality, a bigger screen, maybe a projector and maybe a pair of loud used pair of HiFi speakers, since studio monitors aren’t really meant to fill the room and 32" TV will look tiny from a sofa.