Sony MDR-XB20EX

The eXtra Bass (XB) range of headphones were the most advanced headphones manufactured by the Sony Corporation. The MDR-XB20EX and MDR-XB40EX is a very similar looking pair of headphones, however the main difference is that the MDR-XB40EX has a 13.5 mm driver, and the MDR-XB20EX has a 9 mm driver, and this has the effect of changing their frequency response. In the following sections of this review you can see what the driver looks like.

The MDR-XB40EX earphones have a frequency response of 4 Hz to 24000 Hz, whilst the MDR-XB20EX has a frequency response of 5 Hz to 23000 Hz. This means that the MDR-XB40EX is just slightly better at either end of the sound spectrum. This is a good indication that the technology is at the cutting edge and the MDR-XB40EX is as good as it can ever get using the current technology.

A 4 Hz frequency is as low as you can possible get on the MDR-XB40EX and it can sound quite amazing if you can manage to push the ear buds into your ear correctly. This is because much of its performance depends upon how good the seal between the ear canal and the ear bud is.

The new durable flat cord design on these headphones is very reliable and it is unheard of ever failing. The most typical fault that occurs with the MDR-XB20EX is the voice coil going open when driven beyond its power limit. In order to achieve the wide frequency response, they had to make the coil extremely thin and light, however if you plug the headphones into a very powerful amplifier and turn the headphones to full, then the coil will burn out.

The Sony MDR-XB20EX plastic case uses a unique acoustic cavity design, and the design of its shape produces that deep booming bass and high tone that people love. It is a strange looking shape with an angled ear bud pipe to match the ear canal. The idea is to have the sound pass through the canal without bouncing around the surface, or leaking outside. On the Sony MDR-XB20EX, the main acoustic design principle is to provide a tight seal using a hybrid rubber maternal for the ear bud, and the result is very effective noise isolation and booming bass.

The package comes with three sizes of ear buds, small, medium, and large, and each has a unique colouring scheme of orange, green, and blue respectively. If you need an extra small size then there is an optional version called "SS" available for purchase. If you require replacement ear buds, then they are available from Amazon and eBay very cheaply. The part number for replacements is, REP-EX10A, which consists of three sizes of ear buds.

The driver units consist of 16 Ω voice coil providing a sensitivity of 103 dB/mW. This is actually very good and means that you will be able to hear sounds that you never previously noticed before. The power output is 100 mW, which is loud enough to hear any music at sensible levels. Overall, these headphones are worth the money and if you want to listen to clear music with good definition then these headphones will do the job very well.

Stereo Jack Plug

The wire improvement is also just as important as sound, because the highly reliable wire design of the MDR-XB20EX means that it never breaks. In most headphones, the wire usually fails near the sleeve just as it enters the jack plug, and many people will have come across ones where they have to fiddle with that part to get the sound on both sides. However, on these headphones, the jack plug design is a huge improvement because the cord is flat and strong to prevent it from tangling and knotting. In addition, the plastic also seems to have "memory" to straighten itself.

In the following sections of this article there are pictures showing the inside construction of the MDR-XB20EX and the wire retaining technology.

Extra Bass

I have read all sorts of strange articles explaining that this long part at the back is the acoustic chamber for enhancing the bass. Presumably, the low frequencies bounce around in this at resonance, which would be around 5 Hz, to provide a booming bass. However much of this space is occupied by the wire and its retaining clip.

The part responsible for the booming bass is actually the part that goes into your ear canal, because the way sound waves enter into the ear canal makes all the difference.

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