Earphones, In-Ear Monitors and Earbuds FAQ

It’s easy to get lost in all of the jargon used when describing earphone design, how well they fit in your ears, how they are tested and how they finally sound once you start to listen to music. To give everyone a refresher and make sure all of our readers know what we’re describing in our earphones / headphones reviews, we’ve put together a list of commonly asked questions and commonly used terms on the subject area of earphones.

Feel free to add a comment with any other terms or questions that you have after reading through our earphones / headphones reviews.

What is an IEM? (In-Ear Monitor)
Technical name for in-ear earphones.

What is a Canalphone?
Shallow-insertion in-ear earphone. Refers to IEMs in which only the nozzle is inserted into the ear canal.

What is a Tip?
Soft silicone or foam sleeve put on the barrel – the part that actually makes contact with your ear canal.

What is a Nozzle? (aka Barrel)
Sound-channeling tube on the business end of an IEM.

What are Filters?
Metal or paper screen inside the nozzle of the IEM designed to keep earwax out of the sound channel. Filters are often replaceable in high-end IEMs.

What is a Housing? (aka Shell)
The part of an earphone that holds the driver.

What is meant by a Stress Relief? (aka Strain Relief)
Thicker part of a cord or cable near its end meant to absorb the stress from the cord flexing at those locations.

Here is a close-up picture of an IEM with the various parts labeled:

What is Microphonics? (aka Cord Contact Noise or Cable Noise)
The tendency of IEM cords to carry noise to the earpiece by solid conductance. Cord noise can manifest itself in the user being able to hear the cord rub/hit against clothes while moving. In the worst cases, the user may hear his/her own footsteps or even breathing through a badly microphonic cable.

What are the different styles that IEMs can be worn?
The cords of IEMS can be worn in one of two ways – ‘straight down’ or ‘over the ear’. Straight down simply means that the IEM cord falls directly down from the ear. Over-the-ear means that the wire is tucked behind the wearer’s ear, and this requires that the housings be flipped upside down. Some IEMs are designed to be worn over-the-ear; some have universal wear style; some are prohibitive of such wear. Memory wire or cable guides are sometimes used to keep the IEM cords from falling out from behind one’s ear.

What is a Dynamic-driver?
Dynamic drivers are a traditional driver design that is used in headphones and earphones. The vast majority of mass-market earphones still use dynamic drivers. Dynamic drivers have several advantages, including cheap manufacturing cost and wider frequency response. On the downside, Dynamic drivers often need to be ported for optimal airflow around the driver, which sometimes hurts isolation.

What is Armature?
Design which uses balanced armature (BA) driver(s). Multiple-BA configurations are common in higher-end earphones. In such a configuration, different drivers are dedicated to producing different parts of the frequency spectrum, akin to subwoofer- and tweeter-containing setups in home audio. Advantages of BA configurations include better detail in a narrow frequency range and the ability to be completely sealed (no external airflow).

What is a Digital Audio Player? (DAP)
Refers to a device such as an mp3 or CD player, which reads digital data from a storage medium and converts it into an analog signal.

What is a Digital-to-Analog Converter? (DAC)
Refers to a device such as a computer sound card, which is fed digital data and outputs an analog signal. Every mp3 player and audio card has an onboard DAC chip.

What is an Amplifier? (aka Amp)
Refers to a device that amplifies an analog audio signal. Usually follows the DAC in an audio chain. Every integrated source (such as an mp3 player or audio card) has an internal amp.

What is a Source?
Refers to the source of the analog signal fed into headphones. Can be a single integrated device (such as an iPod) or a device chain (such as Transport->DAC->amp).

What is a Transport?
Refers to the storage medium itself. This could be a computer hard drive, a CD disc, or even a vinyl record.

What is DIY?
Stands for “Do It Yourself” and refers to the practice of building or fixing something without expert intervention.

What is Bass? (aka Lows)
The frequencies below ~300Hz

What are Mids?
The frequencies between the bass and treble

What is Treble? (aka Highs)
The frequencies above ~6kHz.

What is Sibilance?
A specific type of unwanted audio artifact which describes harsh or overpronounced "s", "sh" or "ch" sounds. Typically found in the 6kHz - 10kHz range.

Written by Mikhail Lifshits