For walls with high surface density, such as concrete or brick walls, the direct application of soundproofing cotton may not yield ideal results. What should we do when the sound insulation of such walls does not meet the requirements? Generally, a double-walled structure can be constructed, using different thicknesses and materials for the soundproofing materials. This prevents the occurrence of resonance and also avoids the appearance of sound insulation dips at certain frequencies caused by the same material. The middle cavity has a good spring effect, creating a mass-spring-mass sound insulation configuration. This combination will achieve the desired sound insulation performance.

When used on lightweight walls such as thin plates, due to the inherently low sound insulation of lightweight wall materials and their tendency to resonate, the application of sound insulation materials can effectively dampen wall vibrations. Moreover, the sound insulation materials themselves do not have significant sound insulation troughs, making their performance on such walls highly desirable.