Due to the many drawbacks, attempting to achieve a STC 40 level of blocking with a modular, acoustic ceiling alone is not advised. First, you would need ceiling panels with a minimum CAC 40 rating and a high NRC rating (0.70 or higher). There are limited options for this level of performance. However, one option is Rockfon® Sonar dB (CAC 43, NRC 0.85). Second, is the problem controlling noise leaks through the ceiling due to lights, air devices and other elements. Testing conducted by Rockfon and NGC Testing Services1 shows that these noise leaks can decrease the CAC of the ceiling system by 10 points.