Is the headphone jack on its way out?
Experts say the traditional 3.5mm headphone jack is an obstacle for smartphone design
The Apple iPhone 7 is likely to spark a rapid shift away from the traditional 3.5mm headphone jack on high-end smartphones when it goes on sale this year.
Axiom managing director Faisal Al Bannai says the two most popular operating systems, Apple's iOS and Google's Android, both offer better alternatives.
Al Bannai said: "The 3.5mm audio socket has been with us for more than 50 years, and has been the standard for portable music since Sony launched the original Walkman almost 40 years ago - even longer, if we consider transistor radios. The quality of music reproduction from portable music players has improved exponentially in that time, but the headphone jack will never let us experience that change fully."
To listen to music stored or streamed as digital files, a digital analogue converter (DAC) changes the digital data stream into an analogue electric signal, which then drives an amplifier, which then drives a loudspeaker to produce sound. The 3.5mm jack can only carry an analogue signal, so the DAC must be housed within the player. For a smartphone, the compromise between size and performance limits the quality of DAC, and therefore the music experience.
As an alternative, both Apple and Google also offer audio output via their data connections: Apple's eight-pin Lightning connector, the micro-USB used by Android devices, and wirelessly via Bluetooth. For these, the phone sends digital information, and the DAC can be housed externally, so headphone manufacturers can choose a combination of DAC, amplifier and loudspeaker purely based on performance.
Al Bannai added: "Sending a digital signal puts the headphone manufacturers in control of choosing the DAC, as well as the amplifier and speakers, so each component can be matched for quality. Music fans will be able to get a better experience from their smartphones. This unlocks more of the technology's potential."
Several headphone brands have already premiered Lightning headphones in anticipation of the iPhone 7, and Apple itself owns one of the market leaders, Beats by Dre. The models already on the market are generally high end, but more affordable options can be expected to follow quickly when the iPhone 7 arrives.
"The height and width of any smartphone is now determined by the size of the screen, so having a slimmer handset is now the key to making it more compact, and less bulky to slip into a pocket or bag," said Al Bannai. "At the cutting edge of design, the 3.5mm required for the headphone jack has become the obstacle that stops the case becoming slimmer."
That does not, however, mean the end of the 3.5mm socket completely. The new-generation of headphones will come with an extra cost, so in the mid-range and budget markets the old-fashioned headphone jack is likely to remain a desirable feature. Even as industry experts were speculating about the iPhone 7, Apple launched its new mid-range offering, the iPhone SE, complete with stereo audio jack listed as one of its features.