Diagnosis
Spatial audio processing is stuck on or malfunctioning. The Studio is trying to create a wide soundstage but is canceling out the mid and low frequencies, often triggered by a Dolby Atmos music track or a glitch.
How to Fix It
Turn off spatial audio processing immediately. Say, "Alexa, turn off spatial audio." You should hear a confirmation chime and the sound will normalize. Verify it's off in the Alexa app under Devices > Echo Studio > Settings > Spatial Audio.
If That Didn't Work
Check the physical orientation. The Studio's drivers are directional. If it's shoved in a corner, angled into a couch, or placed on a deep shelf, bass waves get trapped. Pull it at least 8 inches away from walls and corners and ensure the top (where the light ring is) is facing the main listening area.
Heads Up
Some music services automatically enable Dolby Atmos for supported tracks, which can re-trigger this. If you consistently hate the effect, disable "Automatically Enable Spatial Audio" in the same app menu.