The iPhone 6 Review
by Joshua Ho, Brandon Chester, Chris Heinonen & Ryan Smith on September 30, 2014 8:01 AM EST- Posted in
- Smartphones
- Apple
- Mobile
- iPhone 6
Audio Quality
The iPhone 6 is the first non-Android phone to be put onto the Audio Precision APx582 for audio testing. The exact same test tones are used as with Android devices, but they are played back through iTunes at maximum volume. We use the same four static loads as we did with the HTC M8 and Samsung Galaxy S5 for the results you see in the table below.
| 15 Ohm | 33 Ohm | 150 Ohm | 330 Ohm | |
| Dynamic Range | 84.155 dB | 92.281 dB | 92.223 dB | 92.160 dB |
| THD+N | 5.873% | 0.0054% | 0.0032% | 0.0032% |
| Crosstalk (L) | -49.608 dB | -56.239 dB | -71.721 dB | -77.966 dB |
| Crosstalk (R) | -49.831 dB | -56.459 dB | -72.191 dB | -77.983 dB |
| Output Power | 44.04 mW | 26.39 mW | 6.614 mW | 3.072 mW |
| Output Voltage | 812.7 mVrms | 933 mVrms | 997 mVrms | 1,007 mVrms |
| Relative Level (20Hz - 20kHz) | ±0.088 dB | ±0.088 dB | ±0.089 dB | ±0.088 dB |
The first thing to notice is the 15 Ohm load test. At maximum volume, with a -0dBFS signal the amplifier section in the iPhone 6 enters clipping. You can reduce the volume to avoid this, but it does not do as well with really hard loads as the M8 does. You can see the 1kHz sine wave for that below, with the amp clearly clipping at the bottom.
iPhone 6 997 Hz Sine Wave 0dBFS, 15 Ohm Load
For most testing I focus on the 33 Ohm load, as most in-ear headphones have a rated impedance around 32 Ohms. A data comparison to the HTC M8 and the Galaxy S5 is in the chart with the S5 as the clear loser.
| HTC M8 | iPhone 6 | Galaxy S5 | |
| Dynamic Range | 92.074 dB | 92.281 dB | 91.921 dB |
| THD+N | 0.0152% | 0.0054% | 0.0505% |
| Crosstalk (L) | -64.780 dB | -56.239 dB | -44.767 dB |
| Crosstalk (R) | -64.329 dB | -56.459 dB | -44.804 dB |
| Output Power | 47.63 mW | 26.39 mW | 10.63 mW |
| Output Voltage | 1.254 Vrms | 933 mVrms | 592.4 mVrms |
| Relative Level (20Hz - 20kHz) | ±0.664 dB | ±0.088 dB | ±0.081 dB |
Compared to the M8 the iPhone 6 isn’t quite as powerful, but it has lower THD+N and a much better relative level. The relative level isn’t a big deal, as a variation of 0.5dB is unlikely to be heard by most. That the THD+N is 1/3rd the value of that on the HTC M8 is more important, as the FFT below shows a very low noise floor on the iPhone 6 when compared to the one in for the M8.
iPhone 6 997Hz 0dBFS Sine Wave FFT
HTC M8 997Hz 0dBFS Sine Wave FFT
The crosstalk is also lower on the HTC, which is an area the iPhone 6 could certainly improve in. Digging into more depth on the THD+N results provides a bit more context. The HTC M8 has THD+N levels that start at 0.03% but after 2kHz it begins a steady rise up to 0.1% at 10kHz and past 0.2% at 20kHz. In contrast, the iPhone 6 THD+N is 0.03% until 500Hz, rises up to 0.06% at 5kHz, then back down to 0.03% at 9kHz, and peaks at 0.1% by 20kHz. The iPhone 6 will have slightly more midrange distortion but less treble distortion.
iPhone 6 THD+N Ratio Frequency Sweep
HTC M8 THD+N Ratio Frequency Sweep
If we leave noise out of it and look only at distortion then the iPhone 6 does even better. It has a distortion level of -95dB out to 10kHz and then it rises up to -82dB at 20kHz. The HTC M8 begins at -77dB for 20Hz, falls to -95dB until 2kHz, and then rises up to -56dB by 20kHz. The bass and midrange distortion is about equal, but the HTC M8 has far more distortion in the treble.
iPhone 6 Distortion (Noise) Frequency Sweep
HTC M8 Distortion (Noise) Frequency Sweep
Is one phone superior to the other? With the iPhone 6 and M8, I don’t believe so. The M8 is more powerful with lower crosstalk while the iPhone 6 has less distortion and better frequency response. Most notably the iPhone 6 has no results that indicate odd behavior, which we have seen with the Galaxy S5 and other phones. It is a well engineered headphone amplifier provided you do not need to listen to something at maximum volume with a 15 Ohm load.
Can Apple improve this? They could improve crosstalk, though some headphone companies like more crosstalk to help create an image more like a pair of stereo speakers than headphones. They could also support 24-bit audio which can improve on the SNR values here. The test tones are only 16-bit in nature, so the SNR maximum value is around -98dB. The HTC M8 may perform better given 24-bit test tones but would need a retest to verify this. Apple seems to have decided on using Lightning with an external DAC to push beyond 16-bit audio so we will have to wait for devices using that to see.
Audio hardware on phones can still improve a lot to get closer to where the best stand-alone products are. Those are capable of Signal-to-Noise ratios of -120dB or greater, and crosstalk of -110dB or more. How much those would be audible with headphones is uncertain, but when used as a source device with a stereo it may be audible. However, unless high-resolution audio downloads, like Pono or HD Tracks, really start to catch on I don’t see this being a main focus for most of the companies out there. The iPhone 6 is more likely what we will see going forward: good audio quality, but most importantly free of any major issues.
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Toss3 - Thursday, October 9, 2014 - link
The browser benchmarks would make more sense if they used the stock browser on all the devices, not just on the iPhone to make it look good. The Note 4 for instance is scoring around 350ms with its own browser, while on Chrome it is only seeing 800ms. The results should also be in a separate "Web-browsing performance" section instead of the CPU performance one.thackr - Thursday, October 9, 2014 - link
Does anyone else see the green dot lens flare shown here on their iPhone 6? http://www.alternapop.com/2014/10/02/iphone-6-lens...The0ne - Friday, October 10, 2014 - link
"At this point, it’s not really possible to revolutionize the smartphone..."Stopped when I got here. I don't usually cuss but you have got to be shtting me for making such a statement. In your effort to try to write a unbiased review you are already stating that for whatever the reasons the phone may lack it is because nothing can be improve so it's a great phone. I officially hate all your Apple reviews now. This is sickening for any professional engineer to digest.
JC86 - Friday, October 10, 2014 - link
@TheOne: Engineers are constantly tweaking and refining the software and hardware for a better UX and that refinement is great but the bottom line is the modern smartphone as we know it have not had any revolutionary advancements in years. It's a mature product category, plain and simple.tralalalalalala40 - Friday, October 10, 2014 - link
So you're one of those that thinks cars are changing massively every year. "THE BRAND NEW REVOLUTION IS HERE FOR A LIMITED TIME"sgmuser - Sunday, October 12, 2014 - link
"and how Apple’s SoC development is now synchronized with the very edge of semiconductor fabrication technology." You are not kidding right! :-) Comparing Intel's 14nm chips, I still believe Mobile phone SoCs are not coping up with the latest tech. m2c. Samsung (with Exynos) atleast jumped a bit...comparing QC SD or Apple Ax series.Pandian - Sunday, October 12, 2014 - link
Actually, Intel is not in making chips, 14nm or 20nm, for cell phones at large! Such a big company with capacity to supply designer boards to any manufacturer in the handheld 3inch or 12 inch device - and still staying away!Pandian - Sunday, October 12, 2014 - link
Compare these - Apple, etc. and All Pharma! 2-5% on actual R&D by pharmaceutical companies, (esp., the ones pricing cancer and Hepatitis C drugs) and about 95 % on marketing (read bribing the Medical industry - that includes "respectable life-saving Doctors") - vs 20-50% profit by tech companies (Apple, Samsung, Lenovo, HP, etc.) on products made from R&D from this decade! Without the slave labor of China and such countries, even that profit is not possible! Today's pyramids and Taj Mahals!Drugs: Most of these drugs were "discovered" decades ago in govt. research facilities - somehow, they are private intellectual properties today! Even anti-helminths (drugs for cattle parasites) costing ~$1-10 for 1000 pills, suddenly cost up to thousands of dollars each pill, because their anti-cancer capacities were "discovered" as side-effects! Even aspirin, made in third world countries and sold here, costs about ten times from a decade or so ago, due to price fixing!
Your life or $200,000 - pay-up or die, if you have cancer or Hepatitis C.
The target is larger with cellphones and computers - hence the bigger market value of the companies!
Even within the tech industry, the profit of $200-300 for each device is paid once every three years or so - the cost of gasoline for a car is more than that in 2-3 months! The actual leaches that cost the consumer are the cell and cable/satellite companies - thousands of dollars a family in a two year contract! USA still charges the highest fee for cell plans, voice, text and data - taking a bite at each end of the link, i.e., the caller and the recipient!
And, we whine more about the cost of these hand-held toys - that is the purpose and use of most of these "smart" devices! Truly important communication via voice, or the equivalent of the Morse code or ham-radio, is so small - not worth taking care of while driving a 4000+lb missile at 55 to 80 mph!
Both Apple and Samsung will take a dive in the next 12 months
A millionaire on CNBC talked about not being eligible for a phone upgrade for another year - and therefore not having hands-on experience with the recently released phones, Apple, HTC, etc.! That is how you stay rich!
The post seems irrelevant! No! The basic premise of most of the posts here are about MONEY!
xmen77 - Monday, October 13, 2014 - link
There can not be "ideal 6500k" if the other LCD in this all badalso
phonearena.com/reviews/Screen-comparison-iPhone-6-vs-Galaxy-S5-vs-G3-vs-One-M8-vs-iPhone-5s_id3810
this is "ideal 6500k"?
thrasher32 - Tuesday, October 14, 2014 - link
Yeah I'm just gonna say it: Apple is the Bose of mobile electronics, only those who don't know any better buy that junk. Hey it's your money feel free to waste as much as you like.