Adding a subwoofer to your sound system can make all the difference in your listening experience, clarifying both low and high frequencies. (Need a bass refresher? Check out our Beginner’s Guide to Subwoofers.) If you have Sub or Sub Mini in your home, you may have come across the Phase Control setting in the Sonos app. And, if you’ve ever wondered, “What does phase mean for a subwoofer? Why would I want to adjust it?” this article is for you.

What is phase on a subwoofer?

Phase refers to the timing difference between low-frequency sound waves from your subwoofer and higher-frequency sound waves from your main soundbar or speakers. Adjusting the phase changes where a sound wave begins. This affects how the different frequencies merge and how you hear them.

Phase adjustments in a subwoofer are crucial for finding the sweet spot where the bass blends seamlessly into the overall sound experience. If you have your subwoofer bonded to a soundbar, it’s helpful to be attuned to the phase, as the precise timing and integration of sound effects can drastically change your home theater viewing experience.

Why do I need to change the phase on my subwoofer?

Room acoustics play a significant role in how sound waves travel and interact with the environment. If your signal is in phase, the sound will feel very full. If the signal is out of phase, some frequencies are canceled out, which could negatively impact the clarity and fullness of the sound.

When to make phase adjustments

You'd typically adjust the phase of your subwoofer in the following instances:

• Setting up a new system
• Changing speaker locations
• Rearranging the room where your speakers are placed
• Addressing issues with the sound

How do I adjust phase?

Adjusting the phase control for a traditional wired subwoofer can be like finding the right combination to a lock. You might need to try it a few times before it feels just right. Typically you’d slowly adjust the phase knob while playing a bass-heavy track. You’d want to also test the adjustments by listening where you’d usually be, as the effect might vary around the room.

Adjusting the phase control for Sonos Sub or Sub Mini is more like flipping a switch. Open the Sonos app and navigate to the product then select Settings > Advanced Audio > Sub Settings. Choose 0° or 180° and listen for the tone; it will help you gauge the adjustment.

If you use Trueplay™ to tune your setup, you don’t have to make any adjustments to the phase control and this setting will be disabled. Trueplay will optimize the phase of your subwoofer — and any bonded speakers — for the unique acoustics of your listening space.

Bring bass to your home with Sonos

A quality subwoofer like the Sonos Sub and Sub Mini will unlock the full potential of your home sound system, bringing greater depth and clarity to music, TV, movies, and more. But for the best possible listening experience, you want to make sure every setting is just right. The Sonos app makes that easy, letting you fine-tune the phase control yourself or doing it for you with Trueplay.