How do Cherry Bomb mufflers generally affect sound?

Cherry Bomb mufflers generally muffle sound. Cherry Bomb mufflers, or glasspack mufflers, allow only very small amounts of sound to escape the engine and muffler, effectively silencing the car's engine.

Cherry Bomb mufflers are built with special sound-proofing technology that allows them to block the majority of sound escaping an engine, significantly reducing the audible noise of a running car.

The mufflers also block sound from reverberating back through the muffler and into the engine. Although these reverberations aren't audible to human ears, they can build negative pressure in an engine and cause serious damage if they're not blocked from re-entry.