When designing a partition to meet the required STC rating you will also want to consider wall massing (massive walls generally block sound), breaking the path of vibration and sound (staggering studs and decoupling), providing absorptive materials (added

When designing a partition to meet the required STC rating you will also want to consider wall massing (massive walls generally block sound), breaking the path of vibration and sound (staggering studs and decoupling), providing absorptive materials (added insulation), and sealing penetrations (from plumbing and HVAC systems). See the STC Introduction in the Documentation Toolkit for more detail on determining the STC rating of various partition types.