When it comes to home theater, most owners really want to bring the bass, they want powerful, clean, and strong bass. This requires subwoofers, there is no way around it. You can have excellent main speakers, but if you really want to feel the impact and excitement of home theater, you need a subwoofer, and – if possible – multiple subwoofers.
The subwoofer is a critical element of your home theater. Interestingly, there isn’t nearly as much audio coming out of this speaker as you might think; if you were to mute all your speakers except for your subwoofer you might be surprised at how little comes out of that speaker, compared to all the others.
However, what does come from your subwoofer is so extremely important to your overall sound and enjoyment of your home theater. Without a great subwoofer, you can miss entire sections of the soundtrack, and even lose out on important parts of the movie’s story.
Subwoofer placement is a little bit more of an art than the rest of your speaker placement. While there are guidelines that we will discuss, there aren’t quite the same set-in-stone angles and recommendations as there are with the rest of your speakers.
One of the main reasons for this is because subwoofer frequencies are not directional, meaning you shouldn’t be able to detect where the bass is coming from in the room, the low frequencies should ‘seem’ to be everywhere.
Another reason that there is no single recommendation to use is that the performance of the subwoofer is tied to the size of the room (meaning the actual dimensions and air volume of the room). The room impacts the sound of the subwoofer dramatically. The same subwoofer will perform quite differently in a room that is 10′ wide x 12′ long x 8′ tall compared to a room that is 16′ wide x 22′ long x 10′ high.
To add to this issue, where you are in a room also impacts what you hear from the subwoofer. This means that as you move around the room, the audible level of the subwoofer will seem to change, even if there has been no change in volume at the source.
At the most basic level, if you just want the most bass, go ahead and stick the subwoofer in the corner of your room. Putting the subwoofer there will ‘enhance’ the apparent sound level coming from the subwoofer, to some of the seating location in your room. This technique is called "corner loading".
The downside here is that some seats will have more bass while others will have less – the performance of the subwoofer will not be consistent throughout your room. This is why corners are not the most ideal location for a subwoofer in your theater. Yes, you can create what sounds like an increase in bass level, but the performance is so uneven throughout your theater that the bass level from one row to another (and from the left seat to the right seat) can be drastically different.
When you take it out of the corner, that ‘enhancement’ will seem to diminish and the sound level will also seem to diminish. However, you will have a more even performance throughout your room.
So what you should do is put on some music, or a movie scene, that you know and love really well. Let that section repeat, and while it does, move the subwoofer away from the corner.
Move it towards the center of the room a foot, move it towards the seating position a foot, and so on. There is no exact answer to this, again due to the fact that the room dimensions have such an impact on performance.
At each position, sit in your seats and listen. Close your eyes and just listen. You should be able to hear an obvious audio difference as you move the subwoofer around in your room.
The old method of finding the best location for a subwoofer was called the "subwoofer crawl". With "the crawl", you placed the sub in your main listening position, then crawled around the room listening to find where the sub sounded best, then placing the sub there. It was fairly simple in concept, but really not very convenient and not very accurate.
These days, there's a much better way to accomplish subwoofer placement and optimization now. Now, we use software called REW running on a PC or Mac, and a measurement mic. REW plays frequency sweeps and displays a graph of the response from the mic (usually placed in the main listening position). You can then adjust the position of the subwoofer to optimize response, and you can use EQ to further adjust the signal to flatten the in-room response.
To get even better in-room response and performance, you can use multiple subwoofers. Adding additional subwoofers will not remove any of your room’s standing waves (those "nodes" and "nulls" are based on the size of the room). However, adding a subwoofer in a different position can create a more consistent level of bass throughout the room, which means more of your theater’s seats will experience an ideal bass performance.
So if you can, go ahead and get a second subwoofer. Multiple subwoofers will be discussed in another article.