Waterproofing in audio gear is a constantly evolving technology. It is used to make speakers, radios and amplifiers for outdoor and marine use. In this article we are going to take a look at how waterproof headphones and earphones are made.
The terms headphone and earphone are used interchangeably. For the purposes of this article, we will stick to the conventional definitions.
Headphones, also known as headsets, are mobile listening devices that have big chunky earpieces with built-in speakers connected by a headband that either goes over the head or hugs it from behind. Earphones are similar to headphones except they lack the headband and their earpieces are much smaller and connected by an audio wire. Earphones are also known as in-ear headphones, or simply in-ears.
How waterproofing is done in headphones and earphones ?
Headphone earpieces, also called ear muffs, ear pads or ear cups, are of two types: around-the-ear and over-the-ear/on-the-ear. The first is larger, completely surrounds the outer ear to lock in the audio, and prevents ambient sounds from interfering with the music. The second is smaller, rests on top of the outer ear, and lets in a little more ambient sound than the first.
Both around-the-ear and over-the-ear ear muffs are made from PU leather or rexine to make them resistant to sweat, rain and humidity. It keeps the inner sponge and padding from getting wet. The headband pad has a similar water-resistant cover. The frame of the headband is made from waterproof material like stainless steel, silicone rubber and plastic to prevent rust.
All the joints in the earpiece chamber are sealed with glue. Gaps through which water might enter like speaker grilles, ports and around buttons are secured with gaskets and sealants. Further, most outdoor headphones have mylar cones instead of paper. Mylar is more resistant to moisture, and hence, is more suited to outdoor environments.
Waterproofing in earphones is done to safeguard the transducers inside the earpieces. The earpiece cabinets are securely sealed with waterproof sealants to check water ingress. The audio cable connecting the two earpieces is waterproof. In swimming earphones, the cable comes in different lengths to suit different wearing preferences. Some cables are designed to be worn over the ear, others to be tucked under the goggle strap or cap to minimize wire drag.
Earpieces terminate in earplugs, also known as ear buds or ear tips. These earplugs directly plug into the ear canal. They come in various shapes and sizes, and their fit depends on the shape of the ear passage and the curves on the outer ear. Earplugs are fully waterproof. They are made of silicone or soft malleable plastic. Following are the types of earplugs used in waterproof earphones.
Tree-shaped ear buds: These ear buds are shaped like trees and have three layers of soft bendable plastic. They screw into the ear canal to create suction which holds the ear buds in place. They also function as noise-cancelling earphones as they prevent ambient noise from reaching your ears. Tree buds are available in different sizes. They are excellent for swimmers.
Fin ear buds: These ear buds have small appendages in the shape of fins that fit snugly in the contours of your outer ear. They have a ‘twist and lock’ mechanism which creates a water-tight seal over the entrance of the ear canal. The fins keep the ear buds in place and prevent them from getting dislodged during rigorous swimming work-outs. The tips of fin ear buds do not penetrate the canal as deeply as tree-shaped ear buds. They come in various sizes and are great for all kinds of water sport.
Ergos: These are similar to fin ear buds, but do not enter the ear canal, remaining just at the entrance. They are ergonomically designed to fit seamlessly into the curves and grooves of the outer ear. They create a water-tight seal, but also allow some amount of ambient sound to enter the passage. Ergos buds offer a solid grip and prevent water from loosening the bud.
Round/ mushroom ear buds: These are the most commonly used ear buds. They are suitable for everyday use on land. The tips are made of plastic, silicone or memory foam. They are sweat-resistant and can take an occasional shower, but must not be subjected to heavy rain and water jets. They are good for travelling and work-outs in the gym.
Waterproof headphones and earphones come with an Ingress Protection (IP) Rating which indicates their ability to withstand water. Here is a chart showing the different IP ratings and what they stand for.
Devices with a rating of IPX2 through IPX6 are water-resistant. IPX7, IPX8 and IPX9 gadgets can be immersed in water. Depending on what you want to use the earphone for, choose a model with a suitable IP rating. For everyday outdoor use, a rating of IPX6 or lower works fine. For swimming, IPX7 or higher is recommended.