Does Decoupling A Subwoofer Make it Quieter
We’ve discussed the importance of decoupling your subwoofer here before. Decoupling puts some sort of squishy barrier between your subwoofer and the floor. This way, when the driver moves in and out, the vibrations don’t travel directly into the structure of your home. Instead, they go through the air of your room. Can they then get into the structure of the home? Of course! But it reduces the amount of energy that is transmitted. But this often brings a question – can decoupling a subwoofer make it quieter?
The thought process is pretty clear. If you decouple your subwoofer, some of the vibrational energy (that should be making sound in your room) is “lost” to shaking the subwoofer back and forth on the squishy feet. If you were to couple (or securely anchor) your subwoofer to the floor, all the energy would be going to make the sound. None would be lost to shaking the box back and forth. Right?
The Case for Decoupling Your Subwoofer
The reasons for decoupling your subwoofer are clear. You want to reduce the amount of sound the is heard in other rooms of your house (or in adjoining apartments/condos/townhouses). Decoupling eliminates one of the more direct transmission lines. You’ll hear less bass outside the room, and fewer things will shake throughout the house. This alone should be reason enough to decouple your subwoofer regardless of any sound lost.
That said, if there were a subjective amount of sound lost by decoupling, your receiver would compensate for it by upping the trim level (volume) on your subwoofer during the setup process. As long as your decoupled subwoofer wasn’t at its absolute limit trying to fill your room with bass, you’d never notice that it was any quieter.
On top of that, energy is being lost one way or another. If you don’t decouple your subwoofer, there are still vibrations that are traveling into the structure. Would that make your subwoofer sound quieter? We don’t know. Because, in practice, it doesn’t matter. As long as you level-match your subwoofer after adding your decoupling solution, you’ll never notice it being any quieter.
In the end, there is no empirical evidence that decoupling your subwoofer makes it any quieter and a lot of anecdotal evidence that it doesn’t. Decoupling your subwoofer will make the bass quieter in other rooms, which is a good thing. It will also keep your subwoofer from bouncing around during bass-heavy scenes and rattling everything in your house. Usually, we say, “Try both ways and see,” but in this case, just decouple your sub. It’s just better.