Mis à jour le 26 February 2019.
It is the rumour that frightens millions of earbuds and headphones users around the world: Apple may not equip the iPhone 7 with a mini-jack connector. Why? Because the small circular connector prevents the brand from making the famous smartphone even thinner. If you own a set of wire earbuds or headband headphones, you will not be able to use it with the new iPhone 7. However, you probably won’t have to acquire a new set of headphones as it is presumed that a Lightning to female mini-jack adapter will be available to transmit analog sound to the headphones. Is Apple envisaging the right solution’
Towards a 100% digital and HD headphone output?
By suppressing the mini-jack headphone output, Apple could also do without integrating a headphone amplifier to the iPhone 7 in order to save more space. This would also increase the smartphone?s battery life, although the headphone amplifier is not the most energy consuming component – which explains the weak sound performance of the iPhone. The consequence of such a change would be that sound would only be transmitted digitally to the earphones via the Lightning connector. The problem here is that today?s earbuds and headphones were not designed to conduct digital signals but this could very well change?
A DAC directly integrated in the cable
Audeze, the hi-fi headphones manufacturer, set the tone. The Audeze EL-8 Titanium headphones are fitted with a male Lightning connector for iPhone, iPod touch and iPad. It therefore receives sound as a digital signal (up to 24 bits / 96 kHz), then converts it into audible signals and amplifies them. To do so, Audeze placed a power DAC directly in the cable instead of putting it in the headphones, like Bluetooth headphones or some rare models (Sony MDR-1ADAC). This is a concept that got us thinking since integrating a DAC and an amplifier to a cable entails many technical challenges and will undoubtedly drain the iPhone?s battery. Yet, there is also a major interest in using this configuration. Since the cable is detachable, it is theoretically possible to replace it with a different cable featuring a DAC or even use an even better portable audio DAC.
Will a ?real’ portable DAC be adapted to the new iPhone 7?
The portable headphone amplifier with DAC will become increasingly popular with the release of the iPhone 7 if it is confirmed that it will feature no analog output. Many models are iPhone compatible and can handle digital transmission. Fitted with a battery they enjoy a stable current and do not drain the iPhone?s battery. Some models can even charge the iPhone. These are less convenient than a cable which integrates a DAC as they take up more space but are, however, easy to carry.
Will it be necessary to switch to wireless transmission’
Who says wireless today automatically says Bluetooth. Unfortunately there is no non-deteriorating sound transmission method. Only Sony offers true Bluetooth wireless CD quality with the LDAC codec, but only their smartphones, portable players and headphones are LDAC compatible (see our guide about Hi-Res Audio). All the other codecs damage the audio signal and are limited to a 16 bits and 44.1/48 kHz resolution. The best compression technology is CSR apt-X but Apple has always preferred the AAC codec, iTunes native format, which is of an inferior quality. With an iPhone 7, Bluetooth transmission will be available but the quality will not be the highest one can ask for and definitely not high definition.
It is unlikely that Apple will recommend wireless Bluetooth transmission since it doesn’t allow the user to fully enjoy studio quality files. Yet, iTunes and Apple Music should soon offer 24 bits / 96 kHz files. This transition might explain Apple?s decision to equip iPhones, iPods and iPads with an exclusively digital audio output in order to externalize the treatment of HD sound.
What about Android’
The release of the iPhone 7 might encourage Google, whose Android OS is still not fully handling digital output via micro-USB OTG connector. All headphone amplifiers with integrated DAC are Android ready (32 bits / 384 kHz and DSD), but Android is not yet ready. A little bit of competition never hurts.