Moisture in In-Ear Monitors (IEMs): How to Prevent Future Problems

Moisture can cause problems in in-ear monitor (IEM) earphones. The components most affected by moisture in IEMs are the physical filters located in the nozzle (sound outlet), the drivers (speakers), and the cables. In this article, I will explain what happens when these parts are affected and how to prevent them from causing undesirable behavior.

What is moisture?

Moisture is the amount of water present in the air, also called “absolute humidity.” On the website of the Brazilian National Institute of Meteorology (INMET), it is possible to check information about the relative humidity of the air at a given time in a specific municipality. Relative humidity is calculated by dividing the partial pressure of water vapor in the air (g/kg) by the saturation vapor pressure.

When can relative humidity cause damage?

An increase in relative humidity, especially when it remains at high levels — for example, above 60% — for several consecutive days, promotes the proliferation of fungi and bacteria, as well as contributing to corrosion by oxidation in metals.

Are there other situations in which moisture can cause damage?

Yes. When we leave a hot shower, humidity levels are extremely high, and this can be easily noticed, since vapor is visible in the air. In this situation, using earphones without waiting for your hair and ears to dry completely may cause inflammation in the ear canal and/or damage components of the earphone.

How can moisture damage in-ear monitor (IEM) earphones?

Moisture can damage in-ear monitor (IEM) earphones when it is absorbed by the nozzle filters (sound outlet), when it comes into contact with the driver (speaker), or when it oxidizes the metal in the cable.

How does moisture affect IEM filters?

When absorbed by the filters of in-ear monitor (IEM) earphones, moisture can significantly attenuate the sound output in the nozzle. As a result, a volume imbalance occurs between the right and left channels of the earphone, causing the sound to be quieter on one side than the other.

How does moisture affect the driver in IEM earphones?

Excess moisture may cause the driver (speaker) of in-ear (IEM) earphones to oxidize, impairing its operation, or increase the weight of the diaphragm when absorbed by the materials that make up the membrane, resulting in sound reproduction distortions.

How does moisture oxidize the metal in IEM cables?

Moisture oxidizes the metal in IEM cables when the outer jacket surrounding the metal filaments is damaged at some point. Cracks that allow oxygen and moisture to enter are formed through twisting (bending) of the cable. This process may accelerate if the cable’s rubber dries out.

How to prevent in-ear monitor (IEM) earphones from being damaged by moisture

There are two ways to prevent in-ear monitor (IEM) earphones from being damaged by variations in relative humidity levels. They are:

• Using silica gel packets inside the case where the earphones are stored.
• Dehumidifying them with an electric hearing-aid dehumidifier.

Precautions when using silica gel with in-ear earphones

When using silica gel packets to remove moisture from in-ear earphones, it is recommended to disconnect the cables from the IEMs to avoid drying out the rubber. This way, you prevent the cable’s rubber from hardening and later accelerating the oxidation process of the metal filaments.

Precautions when using an electric dehumidifier with earphones

When using an electric dehumidifier with in-ear monitor (IEM) earphones, you should:

• Choose electric dehumidifiers that do not exceed 40°C (104°F), because above this temperature there is a risk of damaging some earphone components, such as the battery or the soldering of internal wires.
• Avoid turning on ultraviolet (UV) lighting if the model includes this feature, as this helps prevent degradation of the resin used in earphones.
• Clean the earphones with a microfiber cloth and a wax cleaning tool before placing them inside the electric dehumidifier.
• Remove the cables before starting the dehumidification process.

Here at Hi-Fi Hub, we published a review of the SoundLink Aid 500 electric dehumidifier, where we discussed in greater depth the use of this type of device with in-ear earphones.