Saturday, 3 December 2016

Headphones: Explaining their Features and Specs


There are different types, qualities, styles, and brands of headphones. You may therefore find it hard to select the right pair of headphones that suits your needs. You might think of going for the celebrity-endorsed brand of headphones, but this is not recommended as you may end up purchasing expensive headphones that do not suit your needs, and their sound quality may also be poor. Even so, it is still not easy for an average person to understand the information provided in the specification sheet of each pair of headphones. The spec sheet is usually written in a complex way, with extremely technical terms and data filling up the entire document without further elaboration as to what each individual specification means.
This piece focuses on headphone features, and also describes the utility of each feature for the user. It will also explain in simple terms what the specs mean. It will therefore help you understand the information detailed in the spec sheet, and also allow you to discern which particular set of headphones is fit for you.
Photo Credit: SoundEncore.com
Headphone Features and Uses
The most important feature of any particular headphone is design that allows it to fit into, or onto, your ears. Each type of headphones has its own unique design, but the different designs can be broadly categorized into the following categories.
1. Canal Headphones
They are also described as in-ear headphones or in-ear monitors (IEM). Popularly, they are known as earphones. They are designed to fit into your ear canal. This design has two key advantages; it allows the headphone to sit near your eardrum, and it also fills the entrance of your ears. Sitting near your eardrums allows the headphones to deliver good sound quality as sound is not muffled through air. Moreover, it is designed to seal your ear canals, and this allows it to act as an effective sealant against external noise. They therefore allow you to enjoy your music without interruptions from external sounds or noise. They are also small in size, and extremely portable. You can therefore use them when you are traveling, jogging, or exercising in the gym. However, their small size means that they cannot give you the same quality of performance as the larger sets of headphones.
The ear tips (or ear buds) of in-ear headphones are built in different sizes, and you can therefore choose a size that will fit properly into your ears. Choosing the right fit is important as it determines the sound quality and performance of the headphones. If you use a pair with an ill-fitting ear-tip, it will keep sliding out of your ears, and its performance in terms of audio isolation will be quite poor, and you will still be able to hear the surrounding noise. Therefore, an ill-fitting ear tip will deliver poor sound quality, and this experience of bad performance may also injure your ears.
2. Supra-aural headphones
They are also called on-ear headphones. They are designed to rest on your ears. They are therefore able to deliver sound down your ear canal. Still, their design allows them to leak out noise to those near you, and some of them can hear the music that you are playing. This can be annoying sometimes. Even so, many people find them more comfortable than the ear-buds of in-ear headphones. However, if they squeeze too tightly onto your ears, then the accompanying clamping will give you some discomfort, especially if you use the headphones for a long time.
Supra-aural headphones are portable, and they provide good sound quality (depending on the quality of the set). They are well-suited for personal entertainment, including watching movies and playing music. If they have a microphone attached, they can be used as general purpose headphones that allow you to communicate with your friends and peers.
3. Circumaural headphones
They are also called over-ears headphones because they are designed to encase your entire ears. Their large size allows them to deliver loud sounds and a good bass performance. They also have a large driver owing to their size, with driver primarily positioned further from the ear drum as compared to supra-aural and canal headphones, and this ultimately allows it to produce spacious sounds similar to those produced by speakers. Even so, their large size makes them less portable than either supra-aural or canal headphones.
Their also offer excellent noise isolation, and this noise-canceling feature makes the headphones of choice for an audiophile who loves gaming, watching movies or training videos, or even for playing quality music. They can also be used for critical listening, and for recording podcasts in a studio.
Open-back and Closed-back headphones
Specific headphones, primarily circumaural headphones, can be described as open-back or closed-back headphones depending on the design of their ear-cups. In open-back headphones, the back of each ear-cup is open, and it therefore allows sound leakage. However, some audiophiles prefer open-back headphones because they deliver natural sound. In some headphones, the back of each ear-cup is partly closed, and they are therefore described as semi-open-back headphones. In the backs of each ear-cup is closed, then the set is described as closed-back headphones; and they offer the best quality of noise isolation as compared to the open-back or semi-open-back variants; but its forceful sound is akin to that delivered by in-ear headphones.
What Specs Mean
One of the most important components of any headphones is the driver. The driver has a diaphragm, voice coils, and magnets, which serve to transduce electrical signals into sound which our ears can hear. In the spec sheet, the entry noted as driver indicates the diameter (size) of the diaphragm (of the driver) in millimeters. Generally, a larger driver delivers better sound performance especially for circumaural headphones.
The spec sheet also has entries for sound pressure level (SPL) and sensitivity. These two related terms describe how loud the headphones are. Sensitivity indicates the efficiency of how the electrical signals are converted into acoustic signals (sound). SPL measures the sensitivity, and is normally expressed in decibels. Sensitivity is also expressed as decibels of SPL per each milliwatt (dB SPL/mW). The normal range of most headphones is 85-120 dB SPL/mW. To put this into context, normal traffic noise is 80dB, and the sound of a jet-take off is 130 dB. Also, health officers warn that prolonged exposure to an SPL greater than 85 dB for prolonged periods of time can lead to partial hearing loss.
The spec sheet also lists the electrical resistance of the driver. This measure is described as impedance, and is expressed in Ohms. A higher value of electrical resistance means that the headphone will consume more power. Therefore, earphones meant for mobile devices have low impedance so that they do not drain the power out of your battery very quickly. However, lower impedance requires a high current, and this current can create unnecessary vibrations of the diaphragm, which cause an audible background hiss. On the other hand, some high-quality and high-end circumaural headphones have impedance exceeding 300 ohms, and this requires them to be powered by an in-built amplifier. This also means that they need a low current to operate, and this in turn creates a smooth sound void of any background noise.
Another item in the spec sheet is the frequency response. It indicates the range (or scope) of audio frequencies that can be produced by your headphones, and is expressed in Hertz with the highest figure representing the measure for treble, and the lowest provides the measure for bass. Generally, most headphones have a frequency response that matches that of normal people, which is 20-20000 Hz. Frequency response can allow you to choose the right headphone depending on what you want to use it for. For example, if you want to listen to music with a better bass quality, then it is recommended that you select a headphone whose bass frequency is low.
The plug type of a set of headphones is indicated in the spec sheet. There are two common plug types; the 2.5mm plug and the 3.5 plug type. The 3.5mm plug type is the dominant plug, and it can fit into the audio-jack ports of a wide variety of devices.
The cord length of your set is also specified in the spec sheet. The most common cable length ranges between 3 feet to 4 feet long. A shorter cable length can inconvenience you.

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