A friend’s recently asked me how I made my home theatre sound so good. I’ve spent quite a bit of time setting up my home theatre system. Some would call it an obsession, I call it getting the most out of my system. 
A surprising number of people are happy to drop a few thousand on a decent sound system and leave it there. After all, you’ve paid your money, it should sound good, shouldn’t it? It did in the store, after all - why should it be any different in the home?
Things aren’t quite that simple. Acoustics are a fickle beast and are notoriously sensitive to environmental conditions. Something as simple as shifting the angle of a single speaker by less than five degrees can easily change the position of the entire soundstage, voices can pop in and out of focus, and instruments can float around the room. Home theatre configuration is key to getting a good sound. And, it doesn’t stop there - you can actually make your speakers sound a whole order of magnitude better by understanding how your room characteristics affect the sound.
The best starting point is to just make sure your speakers are in the right places. If it’s a home theatre, follow the Dolby Guide. Key (and sometimes easy) points:
- Try to make sure that your front speakers are neither too far apart nor too close to each other.
- If you’re planning on listening to music and want to get the absolute most out of your system, you’ll need to sit in the primary position (on your couch directly between your two front speakers). Toe the two front speakers in so the tweeters on each point roughly at your ears (not your forehead).
- If you’re only watching movies and have multiple seats in the room, leave the front speakers pointing directly at the wall behind you. You’ll lose fidelity in a stereo signal, but it won’t matter for most 5.1 encoded movies, as they use positional sound anyway.
- Follow the positioning guide for your rear speakers - most people will put them behind the couch. That’s OK, but they’re actually better off to the side.
- Make sure your centre channel is located above or below your TV directly in front of you. Ideally, angle it so it’s also pointing at head-height.
- Keep everything located symmetrically around the room. Don’t have one speaker further to the left or right relative to the TV or yourself than the other one.
- Make sure there’s nothing between your ears and the tweeters in each speakers. High frequencies are directional, and putting anything in between their source and you will significantly impact sound quality.
- If you have a real subwoofer (one that you either built yourself or paid around a grand or more for), put it wherever. Bass is non-directional and you won’t actually lose much fidelity in practice even if it’s behind (or under) your couch. Ideally put it somewhere so it has a clean path to your ears, but it isn’t as essential as your other speakers.
- If you have a home theatre in a box subwoofer, make sure it’s out in the open and pointing at your ears. Ideally, put it right next to (or under) your TV. Most home theatre in a box subwoofer actually aren’t - they don’t go deep enough to be a true subwoofer. As they emit higher frequencies, the sound they produce is quite directional. So, if you put it to the side or behind your couch, you’ll end up hearing things (like voices) coming from your front and behind you at the same time.
Follow those, and you’re off to a good start. From there, the next most important things are understanding how:
- to make sure everything’s configured correctly and volume levels are correct
- acoustics are actually affected by your room
- to determine how your room is colouring your sound
- to fix your individual room characteristics to improve overall frequency response
Some people try to run their systems from a corner or in a non-symmetrical room. Neither is normally good nor easy to fix. You can actually get some acoustic benefits from a non-symmetrical room, but in most situations, it just degrades the quality.