In today's video, Andrew Welker walks us through how to set your subwoofer up for the most impactful home theater performance.
Hi, I'm Andrew Welker, Axiom Design Engineer. And today, we're going to do a sort of preliminary introduction to where to place your subwoofer in a room. Now, subwoofer and the way that it behaves and interacts with a typical listening room is a very, very complex subject.
And there's all kinds of tools and measurement systems and other things that will allow you to get very, very precise ideas of where you can place the subwoofer for the best response. But, a lot of those techniques don't work well if you don't have a reasonably good starting point.
And conventional wisdom says that you want to take your subwoofer and just slap it in the corner of the room. Now, in many cases, that will give you the loudest bass, but in most cases, it won't give you the smoothest and most linear bass. So, it's a decent starting point, but don't assume that once you've put the subwoofer down and in place, that it should stay there necessarily.
If you're forced into a certain location...and in many homes, the only place that you can put your subwoofer is close to the television set, which usually means that it's going to be behind either the left or right loudspeaker, and probably in the corner, unless you've got an L-shaped layout.
The corner placement is going to give you the biggest amount of what's called, room gain, which is additional output because of the loading of the room boundaries, which we mean the walls and the floor. If you are limited in terms of your placement, you should always, even if you only have a couple of feet to play with in any direction, you should try pulling the subwoofer out from being right up against the corner, moving it to the left or right by a few feet as much as you can.
And as you do this, listen to music that you're familiar with and try and find the position that gives you the smoothest bass. Even a couple of feet of pulling the subwoofer out from the corner can smooth out the bottom end significantly. Now, if you have two subwoofers in your set up, and again, you're fairly limited, you're going to do exactly the same thing.
I always like, when I have two subwoofers is to actually set them up in terms of looking for the best placement separately, and then balance the levels and make the adjustments with both of them playing after you've found a good position that gives you the smoothest bass for each subwoofer individually. If you're not so limited on your placement of the subwoofer having to be behind the left or right main speakers in the system, a really good technique is to do something called the subwoofer crawl.
Now, this may sound a little bit strange, but it really works. The subwoofer crawl is simply a matter of taking your listening seat, either moving it or if you've got a large couch or something, placing the subwoofer as close as you can to the position where you're going to be sitting listening to the system.
Then, connect it up as usual and play some music or movies that have some good little frequency content in them. Now, what you're going to do, it sounds silly but it works, is get down on your knees and crawl around the perimeter, the outside edges of the room, listening for when the bass smooths out.
Now, subwoofers interact with rooms in a way that causes what are called, room nodes, which are peaks and valleys in the response. And these occur at different frequencies, depending on the room and where the subwoofer is placed. Now, these peaks and valleys mean that as you crawl around, you may find some spots where all of a sudden you have very, very loud bass, but it doesn't sound very smooth.
The flip side of that is that you may get into a position where you hear almost no bass at all, or very little. It doesn't sound very full in that position. And now in that position, you are going to be in a room null, where the output of the subwoofer is actually canceling with the size and dimensions of the room.
So, by doing the subwoofer crawl, you can easily listen for a spot that gives you the smoothest, low-frequency bass. And that now is a good position to try out by actually putting the subwoofer in that position, and now going back to your listening seat, sitting down and seeing whether or not that placement actually works.
It's a good, easy technique that doesn't require you to be technical, doesn't require a measurement equipment, and really works in most rooms. Let me know how you make out in the comments below!
