Down-Firing Subwoofer – Placement and Orientation

When shopping for a subwoofer, people come across something different from every other speaker. A driver that is pointed at the ground. No other speaker has a similar common driver configuration. With such a unique configuration, they naturally have questions about potential down-firing subwoofer placement and orientation. Well, we’re here with answers.

Carpet or Hardwood?

With a driver pointed at the ground, your down-firing subwoofer surely requires specific placement and orientation. It can’t sound the same if it is facing hardwood versus carpet versus something else? Is this something you need to worry about?

The answer, interestingly, is no. As we’ve discussed before, the bass waves are so long that the material under the down-firing subwoofer doesn’t substantively affect the sound. You might think that carpet would be more absorptive and a harder surface would be more reflective. You’d be correct…if the sound were a higher frequency. For example, GiK Acoustics Soffit bass traps are very effective down to 63Hz but not much lower. And they are 16″ thick! A thin carpet and the pad underneath does nothing to the bass. You might as well have it placed on the slab that is under the carpet.

Is Decoupling Important?

Decoupling a speaker or other AV gear puts a squishy material between it and the floor. We always recommend you decouple your speakers and subwoofers. A down-firing subwoofer is no different.

You may be worried that the down-firing driver orientation may somehow cause the subwoofer to “walk” as the driver moves, bouncing the subwoofer out of placement. That’s actually less likely the case with a decoupled subwoofer versus one that isn’t decoupled. A decoupled subwoofer will not only stay in place more easily, but also not transmit vibrations directly into the structure of your home. Decoupling will also reduce rattles in your home theater, reason enough to decouple your sub.

Author’s Note: Do not use the included spiked feet. These are often included with your down-firing subwoofer as a way to “decouple” them from your floor. First, that is exactly the opposite of what they do. They pierce your carpet and directly couple (connect) your subwoofer to your floor. Carpet spikes are hard to properly install (especially if your floor is less than level), causing the subwoofer to rattle against the floor.

Sunfire SDS-12 subwoofer
These aren’t true carpet spikes but this sub still needs to be decoupled.

Can I Place my Down-Firing Subwoofer on Its Side?

Some subwoofers are taller than they are wide or deep. To hide them, people often want to place them on their sides. With subwoofers with front-firing drivers, this seems not to be a problem. But with a down-firing subwoofer, surely using this orientation in your placement can make a difference? There was a surface only inches under the driver. Placing the sub on its side means that it is firing into open air. That has to make a difference!

Again, surprisingly, no. Subwoofers are omnidirectional. The bass waves wrap all the way around the cabinet as they leave the driver. We know it seems counterintuitive, but it is true. You can even ask SVS. They sell a line of cylinder subwoofers that have a plate on the bottom. But they say you can remove the plate if you want to add their Soundpath Isolation feet (a great way to decouple them). They also say it is perfectly fine to lay these subwoofers on their side. The plate? It is only there for protection. If you want to remove it, it won’t make a sonic difference.

Wrap Up

Subwoofers are easily the most misunderstood component in a home theater system. That’s because very low bass behaves in ways that don’t really make sense based on what most people know about sound. When you are looking for the perfect orientation and placement for your subwoofer, down-firing or no, just know that the subwoofer and the room work together to create the bass you experience. Also remember, no matter where the driver is located, it really doesn’t matter the orientation of the subwoofer. Just don’t block the driver from moving or plug a port and you’ll be fine.

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