Weatherproof speakers aren't much different from indoor speakers. The main difference is the type of material used for the inner and outer components:
- Indoor speakers have steel frames and grilles are susceptible to rusting, corroding and dissolving. Manufacturers of weatherproof equipment use stainless steel, aluminum or brass.
- Unlike weatherproof speakers, which use mylar diaphragms, indoor speakers have paper diaphragms in the drivers, which are sensitive to humidity.
- Weatherproof speakers need tough casings to protect their sensitive internal components from the elements. A polypropylene finish, resistant to rough handling and inclement weather, protects weatherproof speaker cabinets. The cabinetry can also be sealed with a watertight Teflon finish.
Once manufacturers have assembled their products, they typically undergo a battery of tests designed to make sure they'll hold up to the rigors of outdoor use. The speakers go through ultraviolet light tests, salt-spray tests and extreme temperature tests. Many companies evaluate eachcomponent of a speaker to ensure that it meets or exceeds expectations.
As you probably know, changes in temperature cause materials to expand and contract. Manufacturers of waterproof speakers check their products' dimensional stability to make sure that temperature and humidity changes don't cause damage. How do they do it? Testers measure the speaker components to see if exposure to heat and cold causes warping and damage. They'll also look for signs of weakness or gaps in the gasket -- a ring around the outside of a speaker that surrounds its frame.
Accelerated life tests stress a product to replicate the effects of aging and extreme temperature changes. They help manufacturers improve product reliability. And acoustic stress tests attempt to duplicate what a speaker might sound like after 10 years of use.