There is no doubting the appeal of wireless headphones. Compared to their wire-bound cousins, wireless headphones give their user complete freedom of movement and a health and safety bonus to boot without any of those long cables to trip over. For a long time, wise counsellors warned that there is a price to be paid in significantly inferior sound quality, but in recent years considerable strides have been made.
One of the things to assess is the context the reception question arises in. Is sound quality an issue? Is the listening environment indoors or outdoors? There are three main types of wireless headphones: infrared, radio frequency (RF), and Bluetooth. Each of them have their own advantages and disadvantages, among which are reception matters. To get a handle on wireless reception issues in terms of headphones and the contexts in which they arise, it is necessary to go over some general questions about headphone design and then look at each of the main types of wireless headphone in turn and the specific reception issues that each may encounter.
Overview of Wireless Headphone Design Approaches
There is a simple reason for looking at general design issues first, which is that wireless headphones need to have a certain amount of reception technology built into their architecture. Some designs are more amenable than others to accommodating this.
In-ear headphones are the most minimal design. Their most familiar configuration is as part of an iPod or a Walkman personal stereo, and Apple at one time used the headphone cords as part of their advertising design. Thanks to demand from athletes and keep-fit enthusiasts, cord-free designs have emerged. They are usually of the Bluetooth type, and owing to their miniaturisation, they tend to have limitations when it comes to sound quality irrespective of reception issues.
On-ear headphones rest lightly on the ears and are usually open to ambient sound to a greater degree than either of the other two main designs. They are the most versatile form, and models might be found with all three transmission types.
Over ear headphones start out with a more expansive contour and accordingly are the most amenable to extra components being mounted in order to facilitate wireless reception. They are less likely, however, to appear in Bluetooth form.
Stereo vs. Surround Sound
One use in particular for wireless headphones coincides with the emergence of another distinction, which is the implementation of surround sound. It is difficult to reproduce the effect of five spatially displaced loudspeakers with two directly facing the ears, but games with effective sound design can harness binaural techniques to recreate the surround experience. The only thing lacking is the sub-bass. Because they are typically not required for free roaming, infrared is the prevailing wireless technology at present.
General Considerations for Wireless Headphones
Before going into the specific reception issues that attend each approach to wireless technology, there are some matters that apply uniformly to each platform. They concern transmission station compatibility, battery life, and the presence or otherwise of on board controls.
Transmission Station Compatibility
It is an obvious reception issue and yet easy to overlook. The first port of call for any wireless headphone set is its connection to whatever is delivering the audio signal. Some sets have jack connectors only, while others have a digital coaxial option in addition. For people looking for more portable types of equipment, a transmission station that requires mains power would be a disadvantage. Sometimes, an incompatibility can be as simple as a mismatch between jack sockets, and a converter is all that is required to resolve the problem.
On Board Controls
When there is variability in the reception, for whatever reason, a useful asset is on board control, which saves the user from having to go back to the station or the audio source to adjust levels. There is a price to pay, which is either that the controls diminish the elegance of the design, or else are so small as to be difficult to calibrate accurately.
A major way in which wireless headphones differ from the corded variety is that they need a local power source, normally provided by batteries. A battery low on power is likely to deliver poor reception irrespective of any environmental issues that may also be factors. Some models incorporate a charger into the transmitting station, which doubles as a stand when the headphones are not in use.
Types of Wireless Headphones
There are three main types of headphones. Two, namely infrared and RF, share similar transmitting technology while the other, Bluetooth, is something quite different.
Infrared headphones use the same technology as remote controls. As a result, they share the two characteristics of being fairly short-ranged and needing a clear, unimpeded line of sight between transmitter and receiver. The way that infrared channels are differentiated means that this type of device is relatively immune to interference. And since infrared does not pass through walls, a transmitter in one room cannot interfere with devices in neighbouring rooms.
One aspect of the infrared technology's virtues in confined spaces is that they are particularly useful in cars, either in conjunction with the car's entertainment centre or with portable DVD players. They can be bought in sets so that more than one person can listen to the same material.
Different Headphone Designs and Prices
There are exceptions, but broadly speaking infrared wireless headphones are predominantly found at the lower end of the price range. Over ear designs are the most common, but there are some lightweight airline style in-ear designs.
Radio Frequency Headphones
Whereas infrared headphones cannot receive a signal through walls and are effectively restricted to a ten metre radius, radio frequency (RF) headphones can receive a signal through walls and other obstacles and typically have a working radius of 100 metres or so. RF headphones are vulnerable to interference, and urban settings are particularly difficult to deal with in this respect, owing to the sheer volume of radio traffic in the airwaves. However, some manufacturers have proprietary technologies that minimise this drawback, such as Sennheiser's Kleer technology, primarily designed to deliver full and uncompressed bandwidth.
Different Headphone Designs and Prices
The spread of RF headphones across the price range is broader than is the case with infrared designs. Nevertheless, the same profile holds: most are over ear models, while the same lightweight in-ear airline styles can also be found.
Infrared vs. Radio Frequency Headphones
The following table summarises the relative strengths and weaknesses of infrared and radio frequency headphones. Although RF sets can transmit up to a 100 metres, that is not universally true, so it is advisable to check the performance rating given by the manufacturer.
Typical Transmission Distance
Works Through Obstructions
Vulnerability to Interference
About 10 m
Up to 100m
Moderate to high
As we shall see, Bluetooth headphones are not directly comparable. The technology is affected in different ways by transmission distance and the transparency of obstacles.
The reason for the difference with Bluetooth headphones is that Bluetooth is a short distance technology, originally developed for data exchange between computers and mobile phones. It has taken a long time for Bluetooth protocols to become sufficiently powerful to transmit enough bandwidth to make the sound quality of headphones attractive enough to satisfy serious audiophiles. The 2010s have seen significant advances, however, and the market has matured to deliver perhaps the broadest range of price and design options among the different approaches to wireless headphones.
Because devices as small as a mobile phone can act as transmitter, Bluetooth headphones have a great deal of flexibility regarding the user's mobility, and there are designs that suit running enthusiasts as well as those that appeal to more sedentary types. As they work at short range and are so mobile, questions about obstacles do not arise. And since Bluetooth's data transfer protocol is designed to be secure, interference problems are minimised. The trade-off, as has already been mentioned, in the past has been that sound quality is also minimised, but market pressure has prompted the development of solutions to this issue, and higher-end models now boast excellent sound quality.
Impact of Different Headphone Designs
Although every common type of headphone design is implemented in Bluetooth flavours, it is the lightweight and minimal styles that are particularly popular. More than the other types, Bluetooth headphones include innovative features that make it easy to flip between tracks and switch from audio to phone reception when required.
Buying Wireless Headphones on eBay
For buyers who are at the early stages of researching a possible purchase, the way to begin is with a general search from the home page for "wireless headphones". There are various options after doing a search, either for filtering or sorting. If you are interested in a certain price range, for instance, you can either set a budget as a filter or else sort the listings by price and home in on the desired product that way.
With a clearer idea of the type you are looking for, the search terms can be more specific. For example, to find an infrared set that is primarily intended for gaming, you can be as specific as "RF gaming headphones". Similarly, runners looking for a Bluetooth set might search for "sports Bluetooth headphones". More specific searches of this kind need less subsequent filtering, but there are always ways to refine your search further. With so many different styles and prices, eBay's watch feature comes in handy for keeping track of possible purchase ideas.
The main points to consider when assessing wireless headphones for their reception characteristics are first to settle on a context in which the item is most likely to be used and then focus on the type of wireless technology that is most appropriate, and second, to consider the style and configuration that most appeals to the buyer and verify that it is compatible with the technical requirements of the chosen technology.
The main factors affecting reception are line of sight and interference. Line of sight is more of a concern with infrared headphones, while interference affects RF sets more acutely. Obstacles are less of a problem for RF headphones, but they still have a finite effective range, which is normally no more than a hundred metres. Bluetooth sets, by contrast, benefit from the portability of their signal source to facilitate free roaming for as long as the user's batteries last. They can also be much lighter and more compact than either of the other types. With the aforementioned considerations in mind, buyers are well on their way to being able to select a good pair of wireless headphones.