Acoustic panels absorb sound waves to reduce echo and reverberation, making a room quieter and more controlled. They’re usually made of foam or fabric-covered insulation and placed on walls or ceilings.
Diffusers, on the other hand, scatter sound waves to create a more natural and balanced sound without making the space feel "dead." They’re typically made of wood or plastic with uneven surfaces.
If you want a controlled sound, go with panels; if you want to keep the room lively while preventing echoes, use diffusers, or better yet, a mix of both.