Function of Acoustic Foam: Acoustic foam installed inside speakers absorbs standing waves generated by low-frequency vibrations within the enclosure. Standing waves in speakers often manifest as low-frequency tailing—a lingering low rumble after drum hits, resulting in low-frequency noise. Foam quantity requires adjustment based on testing: increase if bass sounds muddy or tailed, decrease if bass sounds hollow. Polyester fiber acoustic foam is specifically engineered for speaker applications and can also be used in music rooms, home theaters, recording studios, and other environments requiring soundproofing. Usage Instructions: Compared to black acoustic foam, this white acoustic foam is easier to install. For small speakers or bookshelf speakers, simply place an appropriate amount directly inside the enclosure. For larger enclosures like subwoofers or floorstanding speakers, secure a few pieces with double-sided tape to the interior walls, leaving the center of the enclosure hollow. Standing waves primarily accumulate in corners, and the foam's purpose is to absorb these waves, resulting in clearer bass. Therefore, regardless of placement, as long as the corners are addressed, the foam will be effective. Important Note: Our acoustic foam naturally relaxes to a thickness of approximately 1 inch, with a weight of about 0.66 pounds per square foot. It meets E0 environmental standards and B1 fire-retardant rating. Due to its soft, elastic cotton-like texture, compressed foam may appear thinner while expanded foam may seem slightly thicker. Sizes are approximate and subject to variation; weight is the definitive measurement.