Foam Earplugs Versus Pre-molded Earplugs

The two main choices for noise reduction earplugs are foam plugs and pre-molded plugs. Here's how these simple devices compare to each other in terms of effectiveness, ease of use, and longevity. PVC and polyurethane earplugs are also compared.

Foam Earplugs

Since their introduction in 1972, foam earplugs have become the most widely used type of hearing protection due to their ease of use, low cost, and effectiveness. They are made from either polyvinyl chloride (PVC) or polyurethane (PU), both of which are high density, closed-cell materials that function as sound barriers.

PVC foam plugs were the first type of foam plugs available. They have a cylindrical or hexagonal footprint and are stiffer than PU plugs, which makes them easier to insert into the ear canal. Because they are not tapered, PVC plugs tend to stay in place better than PU plugs. They are also less susceptible to moisture absorption, which enhances recovery from roll down under varying humidity conditions

PU earplugs are typically molded into various tapered shapes such as bullets or bells and may even have ridges. They are softer than PVC plugs and often have a smooth skin that helps them stay clean longer.

The choice between PVC and PU earplugs is mostly a matter of personal preference because both cost approximately the same and provide similar levels of noise reduction or attenuation.

Pre-molded Earplugs

Pre-molded earplugs are molded to fit into the ear canal without having to first roll down the plug as with foam earplugs. In order to be effective, pre-molded plugs must be sized to fit securely into both the left and right ear, a feat that is not always easily achieved.

Pre-molded plugs are typically made from either silicone rubber or PVC foam. Of the two types, silicone plugs last longer and are less prone to shrinkage, cracking, and hardening over time.  Pre-molded plugs have a hygienic benefit over foam plugs because they don't involve roll downs using dirty fingers. They can also be washed and reused multiple times.

Custom molded earplugs are made from impressions taken of your ears in order to provide a perfect custom fit. Their effectiveness is highly dependent on the skill level of the person taking the impressions so there is no guarantee that they will provide better noise protection than other types of earplugs. Note that custom molded earplugs are considerably more expensive than other types of plugs.

Durability and Noise Attenuation

Pre-molded earplugs are more durable than generic foam plugs but they are not quite as effective as the best foam plugs, generally speaking. This is due to the difficulty in establishing and maintaining a good acoustic seal in the ear canal. Pre-molded plugs are less pliable than foam plugs and do not expand to fill the canal like foam plugs so proper fit is essential.

The key to using foam earplugs is the roll down. That is, rolling the foam into a thin, crease-free cylinder that will fit about halfway into the ear canal. Some wearers, especially women with small ear canals sometimes have difficulty rolling foam plugs small enough to fit in the ear. Manufacturers have introduced smaller size plugs for such people.

Although foam earplugs are labeled as disposable, they can be reused to a certain extent. With a little care, a pair of foam plugs can last 2 to 3 days, perhaps even slightly longer.