Smartphone Audio Quality Testing
by Chris Heinonen on December 8, 2013 5:15 PM EST- Posted in
- Smartphones
- Audio
- Mobile
- Tablets
- Testing
In many of the examples you have seen so far, you notice that the Nexus 5 has a large issue with the left channel at peak volume levels. As Brian mentions in his Nexus 5 review, it is based on a similar platform to the LG G2 but it isn't identical. Because there are similarities I want to test it out and see if it has the same issue that I see on the Nexus 5.
The test that is causing the large issue on the Nexus 5 is a 1 kHz sine wave, at -0dBFS, at maximum volume. This is the loudest sound that any device will be asked to produce. If you're familiar with the trends in music mixing the past two decades you'll know that a peak of -0dBFS is not all that uncommon now. This chart at NPR shows the average and peak levels for the most popular songs over the past thirty years. Two decades ago testing for -0dBFS might not have been important but it is now. So lets look at this image from the Nexus 5 again.
Now for comparison, we will look at the LG G2.
This looks much better. However the LG G2 is still putting out 0.546528% THD+N into the left channel while only outputting 0.003338% into the right channel. So there is still some imbalance going on here. So why is the issue so much less on the G2 than on the Nexus 5?
The key to this is looking at the scale on the graphs here. While the Nexus 5 peaks are up close to 1.3-1.4V, the G2 has peaks that don't even reach 700mV. Looking at the actual numbers the G2 has a Vrms level of 475.3 mVrms while the Nexus 5 checks in at 843.6 mVrms for the left channel and 982 mVrms for the right channel. The G2 is placing far less stress on its headphone amplifier and keeping it from the output levels that cause this excessive clipping in the Nexus 5.
To look in more detail, we have THD+N Ratio charts for the stepped level sweep that we looked at earlier. First, lets look at the Nexus 5.
We see that the first three volume levels, 15-13, have THD+N distortion over 0.3% for the left ear, while they are below 0.01% for the right ear. From level 12 and below the THD+N levels are practically equal. Now to see how this data on the G2 looks.
We see the first volume step has 0.55% THD+N or so for the left ear, but the right ear is down at a similar level to level 14 on the Nexus 5. The next step drops it to 0.03% which is way, way below where it is on the Nexus 5 at that point. By step 13 they are equal.
The conclusion I pull from this is that both the G2 and the Nexus 5 have the exact same flaw right now. However, the G2 has attempted to hide it by reducing the maximum output level of their headphone amplifier. The Nexus 5 can play louder, but only with far more distortion. Given this I would expect there to be an update to the Nexus 5 at some point that lowers the maximum headphone level to something closer to the G2.
However this doesn't mean that the Nexus 5 is certainly worse to use with headphones. The top 3 settings are ones I would avoid due to the left channel issue, but I might avoid the top 1-2 settings on the G2 as well. If we consider 1% THD+N to be the maximum allowable level, that leaves 8 volume steps on the Nexus 5 that are usable. The G2 has 9 steps that are available to you, and 10 if you consider 0.03% THD+N in one ear to be OK (it probably is).
In the end, the G2 won't play as loud as the Nexus 5 will, but you don't want to play that loud anyway. It has more usable volume steps than the Nexus 5, and otherwise very similar numbers. I'll be interested to see if either of them make further changes to their maximum output levels to remove this issue.
Facebook
Twitter
RSS
188 Comments
View All Comments
JasonQG - Monday, December 9, 2013 - link
I'll be curious to see how the iPhone 5s compares to the iPhone 5. I noticed a definite improvement when I upgraded, at least to my ears' perception.ClockHound - Tuesday, December 10, 2013 - link
Nice to hear you're taking sound semi-seriously with devices that have a semi-important audio task. At least for those who use smartphones for aural communication and music playback.Nice to see the Audio Precision in action. Great unit. However, please, consider putting a little more thought into the scaling of your FR graphs. What appears visually as a huge peak in the htc Beats graph barely has a 3dB rise. That's not a huge peak.
A 1dB rise at 10k is not much of a rise and since it doesn't display enough data, we can't tell if it's a low Q event or not.
The Audio Precision can scale the vertical axis to make plots more informative rather than sensational.
pandemonium - Tuesday, December 10, 2013 - link
Awesome stuff. Keep it up AT!kreacher - Tuesday, December 10, 2013 - link
Great article, would it be possible to test audio input (the mic) in this much detail. Noise cancellation as well as how it does in speakerphone mode / video recording. I know earlier reviews / articles have mentioned this are but it would be great to have detailed numbers like this article.Cyleo - Tuesday, December 10, 2013 - link
This is awesome. I truly love this, please continue this work ;)Any change one of the more recent Sony models makes the test (Xperia z comes to mind)
Pastuch - Tuesday, December 10, 2013 - link
Chris, fantastic article, way to bring me back to Anand. Please include results of the Iphone 4s and any other phones you get your hands on. My girlfriend and I are phone whores, she's Apple, I'm Android. I'm constantly playing with all of our phones and cans trying to find the best audio combo.I run Sennheiser HD-25s, Sennheiser Momentums, V-Moda Crossfade M-80s, and Koss Porta Pros (Awesome since the 80s!).
Best sounding phone I've ever heard:
Iphone 4S sounds way better than the new Iphone 5. It's definitely louder and fuller. Too bad the 4s doesn't have APT-X codec for Bluetooth.
Runner up:
Samsung Galaxy S with Voodoo sound Rom (Note, you need to load a non-standard rom to make it sound great)
The rest:
SGS2 (International Model): Too quiet, poor quality, disappointing dynamic range.
SGS3 (North American Model): Poor quality, lots of cross talk, disappointing dynamic range.
HTC One (Beats Audio OFF): Sounds great, really no complaints. A step above most Android phones. Still miss the Wolfson DAC though.
IPhone 5: Still sounds great but it doesn't live up to the 4S. I'd say it sounds slightly better than the HTC One but the difference is really marginal.
Nexus 5: Sounds better than the SGS2 or 3. The V-Moda M80s sound good because they aren't hard to drive. The Sennheiser HD25 needs the top volumes and the clipping is obvious. The HTC One sounds a little better.
vision33r - Tuesday, December 10, 2013 - link
HTC One audio is a joke. Which features a software sound enhancer AKA Beats Audio which any custom rom can cook into their roms.I've had the S3 with the Beats Audio software and took it off flashed a better DAC amp app.
Traum - Tuesday, December 10, 2013 - link
As a head-fi audiophile, I want to THANK YOU for doing this!MWisBest - Tuesday, December 10, 2013 - link
Nice article, definitely curious as to how my Galaxy Nexus would fare in this, as I'm a bit of an audiophile.hrrmph - Wednesday, December 11, 2013 - link
Awesome topic and write-up :)Keep these coming, please.