Currently, the streamlined out iPhone 7 headphone jack heated tempers. The brunt of a short lightning adapter you want it. But instead to improve the sound, show up degraded the signal quality as our measurements.
One can debate whether Apple’s decision to omit the Jack in the iPhone 7, a Fort – or delete is. Who loves headphone cables, may arrange with the small adapter cable, which attaches the Smartphone Apple. Even with a loss of the lightning adapter, the damage is manageable, finally, you can buy a replacement for 9 euros.
However, it is undeniable that has worsened the sound quality with the introduction of the adapter. We have checked the short cable stub in our audio measurement laboratory. With the adapter on the new iPhone 7 and 7 came plus an iPhone 6S and an iPad air be used. For comparison, we measured the signal quality of the internal Jack 6 S iPhone and iPad air.
The results are clear: on the iPhone 6S, the dynamics to 4.5 DB (a) deteriorates when it plays out a 24-bit music file through the adapter instead of the internal socket. IPad air deteriorates the signal 3.8 DB(a). Also at 16-bit music files the loss are clearly noticeable, if not quite as drastic: here the dynamics to 1.8 DB (a) 3.1 DB(a) on the iPad and iPhone deteriorated.
During the measurements, it was irrelevant whether the adapter on the iPhone 7, 7 plus or iPhone 6s was connected: the results are similar to the decimal. It was noticeable, however, that provides the adaptor on the iPad significantly better results than on the iPhone. This may indicate that sits in the adapter even not a separate D/A converter, but already transmitted the audio signal in analog form via the lightning Jack. Because the lightning chips in the cable can negotiate individually the length with their site in the iPhone/iPad, what is being transmitted, it could very well be. As long as Apple is silent on the subject, here only further testing can bring certainty.
To use the previous Jack as a line connection, so the iPad air with less than 1.0 Volt spends (dBV – 0.2) approximately twice as high voltage as the iPhone 6 S with 0.5 volts (6 dBV). Here, too, the adapter looks worse, to around 1 dBV output voltage decreases. At a higher load of the output socket with low-impedance headphones (16 ohms) the voltage on the adapter SAG but not so strong as before with the internal Sockets. One dBV suffered even a drop of 1 to 2 at the latter, the voltage on the adapter remains largely stable, and dBV breaks only to 0.2 to 0.3.
To judge by these readings, Apple has significantly reduced the output resistance of the adapter to the jacks of the 6s iPhone and iPad air. Is it the iPhone – 6 S-Jack still at less than 5 ohms and iPad at 1.6 ohms, so he is shrunken in the approximately half ohm adapter.
For 30 ohm headphones it makes no difference at the volume, whether they are operated on the adapter or to the internal socket of the iPhone 6 s / iPad air. Headphones with a lower impedance play up on the adapter louder, higher impedance headphones (until about 80 ohms are recommended on the iPad) are loud on the internal sockets of the iPone 6s and iPad air.
However, the distortion factor is not affected. He remained constant at very good 0.001 and 0.002 percent over our entire series of measurements with höherohmigen resistance by 30, 80, 250 and 600 ohms.
44.1 kHz better than 96 kHz
The measurement results with different sampling rates were curious. can iTunes under iOS no files 96 kHz playback, but with only 44.1 and 48 kHz. It has a good reason, because also the D/A converter of the iOS devices are only up to 48 kHz. Nevertheless, there are some iOS programs that still play 96 kHz files, include the DAW Cubase and the file program Goodreader (with which we were ultimately all measurements under iOS10). However, both programs before converting the 96 kHz files and to cut the high frequencies with a low-pass filter. Cubasis is the knife here at about 18 kHz, the Goodreader only at 19 kHz. We got the best rate at 44.1 kHz, here all devices transmitted frequencies up to 21 kHz. In all cases, the response remained including perfectly linear.