When selecting headphones for a particular job, there are many different specifications, attributes and general terminology for them What do they all mean?
Even if you understand what these headphone specifications mean, it is not always clear what difference it may make in practice. Sometimes it may be important – other times not.
Understanding the headphone specifications and terminology can help you cut through all the sales literature, or help talking to a sales assistant when buying a pair of headphones.
Type of headphone
One of the first and possibly most fundamental aspects of any headphone, earphone, etc is the actual type it is.
There are several different types of headphone and earphone, and although they generally work in the same way, the actual format of the headphone governs many of its properties and how it can be best utilised. Having an idea of the different properties of the various types enables informed choices to be made when buying them.
- Over ear headphones: Over ear headphones, as the name implies are the traditional headphones that have a surround cushion or ear-cup that fits over the ears. These are sometimes more comfortable than the on-ear versions, although it can be a matter of personal preference. However they take up more space which can be an issue if they need to be fitted into a bag, etc. when listening on the move.Generally the over-ear headphones are the type that is used for high end listening, and serious listening, audio and video editing and a variety of audio visual applications.In terms of their performance over-ear headphones often provide superior audio quality to other types as the larger housings can hold larger audio drivers which can also offer a greater power level. The space limitations of other types do not force the same compromises on the technical performance.In terms of performance, top end over ear headphones usually provide wider sound impression than in-ear versions and this can result in a more natural sound. Also the larger drivers enable a larger displacement of air giving rise to a fuller bass response.The ear cushions or ear cups in over-ear headphones can provide a comfortable fit for longer listening periods as well as giving a large amount of sound insulation – a bonus if noise cancelling is not an option.
- On-ear headphones: On-ear headphones are also called supra-aural headphones and they have a band that fits over the head, but the cushion around the audio transducer fits onto the ear and not around it. This gives some sound insulation from the outside world, and they generally occupy less space than the full over ear versions. This can be useful if they are used on the move and need to be packed away into a small space.On-ear headphones are available in passive formats and also with active noise cancelling, although being on-ear, they tend not to offer quite the same levels of noise insulation or cancellation dependent upon whether they are passive of active.Overall it is often a balance between comfort, noise insulation / reduction, overall performance and size.
- Earphones: or Earphones are sometimes called in-ear headphones. They often have different sizes and types of ear cushions but they are often made from silicone, plastic or rubber to achieve a comfortable and secure fit in the ear. Very high end earphones may even be custom fitted by an audiologist to get the best fit possible.The performance of earphones is improving all the time, and even though the over ear headphones are generally accepted to offer the best performance, in-ear ones can come a very close second for many situations. An additional advantage is that they are much smaller and can be much easier to pack away when travelling.
- Earbuds: The term earbuds is often used for a variety of types of earphone, but strictly speaking, earbuds are a little different to earphones. They are differentiated from earphones by the fact that they are held in place by the concha ridge at the centre of the outer ear.This type of earbud may not be comfortable for all people to wear, especially if your ear is not the standard shape. Also sometimes earbuds may fall out for the same reason. However when earbuds do work, they can be particularly good.One of the advantages of earbuds is that some typically allow in ambient noise and this means outside noise and sounds can be heard. This can be quite important when you are outside because you don’t feel so isolated from the environment. This can be very useful for personal safety when outside as you will have more awareness of what is going on around you. Crossing roads and generally walking in the street, it is surprising how much you rely on hearing what is going on around you.
Open & Closed Back Headphones
For headphones. one of the first things seen in the description is that some are open back and others are closed back headphones.
It is useful to understand what open and closed back headphones are and a little about their advantages and disadvantages, and why it is an important parameter for headphone specifications.
- Open back headphones: This is probably the most obvious form of headphone to have. As the name implies, the headphones have an open back. This means that the diaphragm of the earphone can move more easily because it does not have to compress the air in the closed back. This leads to good reproduction – it is especially good for the level of efficiency and also the frequency response.There are two downsides to to open back headphones.. The first is that others can hear the sounds from the headphones and this may not always be wanted. The other is that external sounds will be heard more easily and this can distract any listening.For top end analytical listening at home or in a studio open-back headphones are often thought to be the best option. These models allow air to pass through small holes or slits in the ear cups – hence the name open back. The open back prevents the build up of pressure within the headphone and this reduces the levels of distortion. Open-back headphones often sound more natural and expansive, but the open back means that sounds from outside can often be heard when listening, and conversely the material being listened to can be heard by others close by.
- Closed back headphones: As the name indicates, closed back headphones were completely enclosed.In contrast to the open back headphones or earphones, these had a much higher level of isolation from surrounding noises as well as reducing the sound to bystanders. However, having to compress the air in the cup behind the earphone diaphragm required more energy and the quality of reproduction is not always as good, although with modern technology, there is often little if any difference.
Some high end earphones use a semi-open approach, utilising the best of both approaches. Often only a very small slit in the casing provides sufficient for the performance to be improved, whilst still retaining many of the advantages of being closed.
Headphone Frequency Range
One of the key performance parameters for any set of earphone, headphones, etc is the frequency response.
This may seem like overkill, but frequencies outside the normal hearing range may not be heard, but they can be felt and they add richness to the overall listening experience. That said, the input frequency range from the music source may use compressed files for which the frequency range is only likely to extend to 20 kHz maximum.
So in some circumstances there can be benefits to having an extended frequency range but be mindful of the overall limitations of the various systems when considering what frequency range is needed.
Also be aware that when listening on public transport, etc, external noise is likely to make a difference anyway and the effects of super-high fidelity may be lost.
However when making a choice of headphones or earphones, a frequency range of 20 Hz to 20 kHz is a good starting point – most reasonable headphones should be able to attain this without too much difficulty. If you have good ears and you are going to listen more intently to music and have good source equipment and material, then going for a set that has an extended specification is probably a good idea.
Another important headphone specification is its impedance. It is probably less important than it was years ago when both high impedance and low impedance headphones were available. Nowadays, the high impedance ones are only rarely seen.
The impedance can be important because of the power needed to drive the headphones and whether the output of the device is suited to the headphone impedance.
Typically most low impedance earphones and headphones are suitable for most of today’s devices.
Typically low impedance headphones have impedance levels of less than 100Ω and are suitable for a host of different devices including iPods (if they are still in use) laptops, mobile phones and the like.
High impedance headphones, typically have impedance levels of 250Ω and above and are more often used for high quality sound reproduction for items like hi0fi systems, video editing and more.
Many headphones and earphones offer a wireless capability. In fact this capability is increasing in use so that long wires are not needed and a simple and easy connection can be made without the issues of faulty connectors as well.
Wireless headphones and earphones typically use a Bluetooth wireless connection, so if you are considering a set of wireless headphones or earphones, then check that your music source is able to support Bluetooth. Most mobile phones, iPads, tablets, laptops, etc will support it, but if you are using another device, ensure it can accommodate a Bluetooth connection.
Although wireless headphones are ideal for many situations, some Hi-Fi purists say that the Bluetooth connection compresses the audio and hence the same fidelity will not be achieved. For most listening and listeners the difference between wired and wireless will be inaudible, but if you are worried, then set up an experiment, or visit a showroom where you can get a demonstration.
When selecting wireless headphones, there are some additional specifications to consider:
- Battery operation time: Wireless earphones and headphones need to have their own batteries and the life or period over which they can be sued between charges is important. You don’t want to be charging them very frequently as this can become very tiresome and mean they may not be usable when they are needed.
- Battery charge time: Normally the batteries in a pair of wireless headphones can be charged relatively quickly, but they often seem to need charging just as they are required for use. It is at times like these that charge time can be important.
One of the key aspects of any earphone or headphone will be its comfort, especially if it is to be worn for any period of time. Often it is the over ear headphones where this can be particularly important because these tend to be used for high quality and professional use where long periods of use are common.
Although earphones and especially headphones might appear comfortable for a short period of time, their overall comfort becomes very important when they are worn for extended periods.
Extended listening of music, video editing, audio editing and the like all require use for extended periods.
The over ear style of headphones have soft surrounds which help, but even these can become uncomfortable over longer periods. It is well worth consulting some of the reviews.