Deep analysis of iPhone5 sound quality evaluation report

Within two days after the launch of the iPhone 5, the famous iFixit and Chipworks websites respectively sent the disassembly of the mobile phone and the layout of the important chips in the iPhone 5, so that we not only saw Apple's newly designed A6 processor, but also There is a chip with the word Apple printed on the chip. Because the Cirrus Logic LOGO appears on the edge of the wafer after etching the package. By model and similar chip analysis on the iOS device, we can confirm that this is Apple's customization to Circus Logic. The digital power amplifier chip is used for headphone output amplification. And we made a mistake in the past evaluation, I mistakenly believe that the audio analog output of iOS devices comes from inside the SoC chip. Today we are here to make up the class with everyone.

Let's look at the Cirrus Logic chip in the iPhone 5 disassembly. The model on the chip is Apple 338S1117. After etching away the encapsulation layer, we saw that Chipworks gave the words of the chip maker Cirrus Logic, which should be customized by Apple to Cirrus Logic. The model number of this chip is 35L19. There is no such product in the official Cirrus Logic product catalog, but the approximate model is the 35L00 series [including 01/02, the package power is slightly different]. We found the 35L00 series chip, which is a small-sized Class-D chip specially designed for mobile players and low-power players. It supports Cirrus Logic's unique Hybrid Class-D mode. ], the main role is to up-convert the signal, up to 192kHz, theoretically can achieve a higher signal to noise ratio. Of course, Apple's customized 35L19 is specific, we are not clear, but because Cirrus Logic has a lot of technology available in digital amplifiers and audio, Apple's 35L19 may not be a Class-D chip, but changed the modulation method. Digital amplifier. For mobile phones, there seems to be no need for a separate digital-to-analog conversion process before Class-D.

After seeing this chip, we also realized that we had neglected chips from Cirrus Logic that might be found in every iOS or even iPod device. We found this through the disassembly of iFixit, and their naming rules are very similar. The list is as follows. From the table below, we can see that except for the chip models used on the iPhone 4s and iPad 3, the other chip models are not the same, but the order of their models is very obvious, and the product models released at the same time are very close, and earlier The product number is also smaller. The ability to find these rules also benefited from such great sites as Chipworks and iFixit, but they did not determine which chips must come from Cirrus Logic in the early days, but it is certain that products after iPhone 4 are from Cirrus Logic's custom chips. . Let's take our regular test project below.

The chips from left to right are: red: Qualcomm PM8018 RF power management chip; orange: Apple 338S1131 power management; yellow: Hynix 16GB NAND Flash; green: Cirrus Logic custom audio chip; blue: STMicroelectronics L3G4200D triaxial; cyan :WiFi module

iPhone 5 Smartphone - Logo on the Apple 338S1117 chip profile

In accordance with established practice, we conducted a set of objective tests on the headphone output of the iPhone 5, and the test was still in the form of a professional-grade sound card input, combined with common analysis methods to provide intuitive measurement results. The actual playback level of the iPhone 5 is -6.6dB, and we compensate it to the standard level of 0dB during the test by the recording device. We know that the iOS devices after the iPhone 4 basically set the output level to -7dB, and the output level of the iPhone 5 is slightly higher.

iPhone 5 smartphone - frequency response curve

iPhone 5 smartphone - noise distribution

iPhone 5 Smartphone - Total Harmonic Distortion

iPhone 5 Smartphone - Intermodulation Distortion

iPhone 5 smartphone - resolution curve

iPhone 5 smartphone - frequency response scanning

iPhone 5 Smartphone - Separation Test

iPhone 5 smartphone - resolution frequency analysis

iPhone 5 Smartphone - Frequency Response Scan @48kHz

Since iOS devices have always performed well in objective tests, the objective performance of the iPhone 5 is also reassuring, but the signal-to-noise ratio and dynamic range have reached the theoretical limit, slightly better than the new iPad, with the iPhone. 4 and the iPhone 4s is improved compared to the signal-to-noise ratio of -95dB. The overall performance of the RMAA test chart can also be seen. In terms of distortion, the results are equally good. However, it can be seen that its stereo separation performance is not good. This time, it is not the problem that the separation of high frequency single channel appears on iPad3 and iPhone4s, but the whole resolution is kept at 80dB. I don't know if this is Design mistakes.

Subjective sense of hearing: iPhone 5 and the iPod touch and iPod nano 7G are all equipped with Apple's latest earbuds, EarPods. However, we will not evaluate EarPods in today's evaluation. It is taking the opportunity, we will then specialize The release of the evaluation, it can be revealed that it has certainly improved relative to the previous generation of products, and the special shape has a special corresponding effect on the listening experience.

In the past many iOS device evaluations, we have been talking about their sound difference is very small, from iPhone 4, iPod touch 4 to new iPad, the difference between the sound of many iOS devices before iPhone 5 is better than iPod nano and The iPhone 4 is smaller and there is basically no difference. For this reason, we also carefully compared the evaluation before the evaluation. However, the style of the iPod Classic is still quite different from that of the iOS device. What will happen to the iPhone 5 today? It is not the same as the previous iOS sound, the difference in overall sound performance is also the largest ever. Below we take the performance of the iPhone 4 as the main reference. In the test we used as many of the headphones as we could.

The output level of the iPhone 5 is slightly higher than that of the previous iOS device. From the small earbuds that are easy to drive, the output power is slightly larger. No matter what headphones, including the headphones, the volume difference of the output is very small. The iPhone 5 is only slightly larger, and the basic output volume under high-impedance headphones is basically indistinguishable. However, the overall driving force of the iPhone 5 has improved, and the sound style has also changed. This change is somewhat similar to the output of the headphone amplifier. The whole sound begins to become compact, the low frequency begins to converge, the resolution is improved, etc. Of course, the iPhone 5's relative iPhone 4 has a much smaller change than the headphone amplifier, but it's still easy to hear the difference.

The sound of the iPhone 5 has become more compact than that of the iPhone 4 and other iOS devices. Maybe someone has to ask, is the iPhone not already "white water"? Can you listen to it again? The iPhone 5 still maintains a neutral style, but the more compact sound performance is most evident in the low, medium and mid-high frequencies.

Low-frequency performance: When the iPhone 5 is paired with some in-ear headphones, the low-frequency changes are very obvious. The iPhone 5 makes the low-frequency more tight, not so loose, because the low-frequency sense of the in-ear earphones is more partial and scattered. Let the low frequency quality be significantly improved. For example, under the headphones of Shengmei E10 and Vsonic GR07, its low frequency becomes obviously more flexible, the transient is better, and the resolution is also improved in the deeper low frequency. In some BASS performances, it is obvious that there are transient details and good and firm sounds. The sound of the E10 is relatively thicker than the low frequency itself. This change makes the E10 bigger and the sound more balanced. But the low frequency is relatively less earphones, and the low frequency style is different. For example, GR07 earphones, Edifier H850 headphones, Aurvana Live! headphones, their low and medium low frequencies will become better texture, better transient, but the mid-low frequency part is not so full. Of course, the difference in headphones is relatively small.

Mid-range performance: The mid-range change of the iPhone 5 with small earbuds is very obvious, especially in the male voice, the thick and full-bodied male voice under the iPhone 4 and iPad has become a more stereoscopic, slightly younger, but not losing texture. The mid-low frequency part of the sound becomes more compact, which makes it less enveloping, but the image is also improved. In terms of female voice, the thickness changes little, but the intermediate frequency is relatively harder for the iPhone 5, and the iPhone 4 is softer, so on some headphones that are more rigid, the vocal sense will be a little worse. For example, Aurvana Air, Aurvana Live!, but on the original thin headphones, the progress is also obvious, such as the Rambler H850, and even AKG K141MKII.

The biggest change of the iPhone 5 IF is mainly in the middle and high frequency bands, and its control power is obviously better. In the large-scale symphony, the sound level is better under the big dynamics, and the explosive power of the brass and string music with more medium and high frequency components is obviously more. Strong, the sound is also cleaner, and the texture has been improved.

High-frequency performance: The high frequency of the iPhone 5 is slightly harder than the iPhone 4. This difference is not as high as the mid-range and low-frequency, but it seems to be slightly weaker than the iPhone 4 in high-frequency ductility because its sound is still a little tighter. Not as smooth as the iPhone 4. With Aurvana Air, Aurvana Live! In this way, the performance of the headphones is better than that of the iPhone 4, the sound density is better, the transient details are better, and the explosive power of the plucked instruments is more full and delicate. The iPhone 4 has become a softer style. In the high-frequency and mid-high frequency parts, it is also affected by poor resolution, and the sense of hearing is noticeable.

Summary: The overall sound quality of the iPhone 5 is slightly improved compared to the previous iPhone 4 and other iOS devices. Relatively speaking, the dynamics of the whole sound are obviously improved under the small earplugs. The low-frequency resolution can feel different degrees regardless of the headphones. Upgrade, relatively speaking, the iPhone 5 low-frequency style will be more compact, more suitable for the headphones with a lot of low-frequency sense. The IF trend is the same, but on some headphones, although the vocals are more solid, but there is no soft stretch on the iPhone 4; it is helpful to improve the quality of strings and brass in the middle and high frequency parts. In the high-frequency and high-frequency parts of the details, the tight sound does not seem to be natural and smooth. The iPhone 5 is also one of the most vocal changes in iOS devices over the years. Although the resolution is not ideal, it is also a rare little improvement or small change.