Building a Linux Media PCby John Littler
In this article I'm going to look at a particular sort of setup of a Linux home theatre PC — one where the primary consideration is space. Suppose you have a small studio apartment, or a bedroom or study where you want to work on your computer, watch movies and TV, and play music and maybe games as well.
If you did things the normal way, you'd have a TV and DVD player, a computer and monitor, a CD player, amplifier, and speakers. If you're extremely finicky about sound quality, for example, and already have expensive audio gear, and if you cringe when you hear poor quality audio, you'd better stick with at least part of that. For people who can live with somewhat lesser quality, the media PC can be quite OK. There are options to make it sound better than a standard PC from the local warehouse store, but they cost more. We'll explore those shortly.
Let's consider an ergonomic issue first: screen size. Most people like to lounge while watching movies. This implies that, even if you do have a super-comfy work chair, you'll sit further away from the screen for entertainment than for work. This will require a larger screen than the basic minimum necessary for computer work alone.
There are rules of thumb for movie or TV screen size, but they tend toward recommending extra large screen sizes which don't fit our compromise, so we're I'll ignore them. The next time you're at the movies, measure the effective screen size by putting up your hands and framing the screen, then measure the distances between your hands. When you get home, sit where you'd want to, put your hands in the same position, and project that size onto the position of the screen. If you choose where you sat at the movies, this could be enlightening. If you chose to sit down the front, the results won't be enlightening at all ... you just want an enormous screen. Next, ask yourself whether the screen has to be where you projected it.
The closer it moves to you along the projection path, the smaller it appears. For example, suppose you're holding your hands out like a film director, about 15 inches apart. If the monitor is at arms' length, it will need to be 15 inches across. If it's on the other side of the room, it needs to be much larger to appear the same size.
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The problem with a small screen is finding a comfortable position when you're close. You might need a little ingenuity here.
Let's face it, most PC speakers suck. They have nasty little drivers and built-in amps that lack headroom. No one seriously intended them as high fidelity devices — and they aren't. Many of the three or more speaker box solutions are little better. Some are even worse.
One of the problems with badly executed surround sound box sets, besides cheap components, is the cutoff frequency for the bass box. Very low frequencies are non-directional — that is, you can't tell where the sounds come from. Ideally, the bass speakers in this sort of system will only operate in the non-directional frequency band. The satellite speakers should handle frequencies down to this point (or, better, an octave below) and then the bass box should take over. In most consumer models of this system, the cutoff point is nowhere near the non-directional point. To add insult to injury, the bass speaker will frequently generate upper harmonics of the sounds it should be producing. This is especially bad if the bass box is reality churning out sounds in the midrange.
What does all that mean? These systems do sound bigger than ordinary PC speakers but that's the best that you can say about them. The mix you hear will have little resemblance to the one the sound engineer slaved over. At worst, speech intelligibility will suffer and you'll cry when you hear violins, though not because of the sadness of the music.
The extent to which any of this is upsetting is intensely personal, so without turning this section into a book, I'll just add a few points. For a small-scale setup, I'd forget about surround sound. Small, self-powered, bi-amped studio monitors are a nice option here. Yamaha, Genelec, and Tannoy (amongst others), make reasonably priced models, and the models are quite small. If you use this approach, though, you might need a small mixer to handle the cables.
Another alternative is to purchase a pair of high quality headphones from a studio supply shop. This is also a nice if you need to keep the noise down, but lots of people don't like to wear headphones for long periods of time. Once again, the small size and combination of the speakers mean that you won't hear the sound engineer's mix.
In the search for a one box solution, you could buy a Sony PlayStation2 and its Linux kit, or you could purchase an Xbox and perform possibly illegal acts on it to make it into an all-purpose computer. In an earlier article I looked at the PS2 Linux kit, which works fine for basic computing needs. It could be quite a good solution if you already have the console and want to play a lot of PS2 games.
Instead, we'll consider running a normal PC. The issues that arise are performance, silence, and maybe looks. Adequate performance is easy to provide. We don't want to edit video, just watch it, so any newer setup will work just fine. That's true of music as well. If we want to store movies, TV programs, or music, we'll want the biggest hard disks we can afford. If we want to play PC games as well, then in addition to the possibility of dual booting we'll want the highest hardware specs we can find.
Having a relatively silent PC is a big plus here. Constantly straining to hear over the whine of fans and hard drives will make you grumpy. Your options are to put a a silencing kit over a noisy PC or to buy a quiet PC in the first place.
There are many boards suitable for a project like this but one wacky (in the context of this article) alternative I just came across is the Soyo SY-P4VAL. This is relevant if you don't particularly want to use the box as a computer; it does all the media playing from BIOS, without needing an OS!
I started with a P4 board and a really nice looking cast metal compact case from Hoojum.com. It has 1 Gig of RAM, 264 Gigs of disk space, and a 3.3 GHz CPU. That's more than enough for what we intend. The setup is capable of serious work. As well, it looks nice, which is part of my goal.
The computer came with Windows XP, so the first thing I did was get rid of it entirely. I had an old SuSE 8.4 CD set around and also a Gentoo starter CD so I started with those, but the old SuSE couldn't catch the video card or monitor and wouldn't let me set it manually, so I moved onto Gentoo. Gentoo is a really nice way to do things if you start with some Linux knowledge, as the system and apps all end up being optimized for your setup. Unfortunately, it needs broadband to update packages and to avoid some heavy mucking about to do the installation without importing any files. I did the heavy mucking only to find that the bootloader Grub couldn't and wouldn't (given options) find the kernel. A few swear words later, I decided to try one of the easy distros. Mandrake 9.2 installed without difficulty. I then upgraded it to 10.
There's no particular reason why you couldn't use your own favorite flavor of Linux for this task. There are also music studio add-ons in both Debian and RPM format, but that's a different story for another article.
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