How do I completely disable a “phantom monitor” on Windows? (RTX 3070 + LG Soundbar SK6FF via HDMI)

Managing Unintended Display Detection in Windows: A Guide for HDMI Audio Devices with NVIDIA RTX 3070 and LG Soundbar

Introduction

Many users have encountered a common issue where Windows misidentifies certain HDMI-connected audio devices, such as soundbars, as secondary displays. This misinterpretation can lead to system instability, visual flickering, and audio configuration difficulties. If you are using an NVIDIA RTX 3070 GPU with Windows 11 and an LG Soundbar SK6FF connected via HDMI, you might notice that your system perceives the soundbar as a second monitor, despite it functioning solely as an audio device.

Understanding the Issue

When an HDMI connection is established, Windows and graphics drivers communicate with connected devices through the Extended Display Identification Data (EDID). Sometimes, devices like soundbars or speakers send EDID information that misleads the system into recognizing them as monitors. Consequently, Windows creates a “phantom monitor,” leading to various display and audio configuration issues, including:

The appearance of an additional display (e.g., Monitor 2).
System treating the device as an extended or disconnected display.
Flickering screens and other visual artifacts.
Loss of audio options when attempting to disable the device as a display.

The goal is to prevent Windows from treating the soundbar as a monitor while retaining its audio functionality.

Potential Solutions

Disable EDID Detection for the HDMI Port

One way to resolve this is to prevent Windows or the graphics driver from reading or applying the EDID data to that specific port. This can be achieved through specialized display management tools or driver configurations. However, such options are often complex and might not be officially supported.

Use Device Manager to Disable the Display Functionality Without Turning Off Audio

Since disabling the device entirely removes the audio functionality, a more nuanced approach is necessary. You can attempt to disable the “Monitor” role in Device Manager for the phantom display:

Open Device Manager.
Locate the display device associated with the soundbar (often under “Monitors” or “Display adapters”).
Right-click and choose Disable Device, but ensure you do not disable the audio adapter or the HDMI port driver itself.

This approach may help Windows stop recognizing the soundbar as a separate display, although results can vary depending on driver behavior.