We spend a lot of time watching and listening to our smartphones and tablets. The younger you are the more likely you are to turn to them for watching a movie or TV show instead of an actual TV. For a lot of us it is our primary source of music with our own content or streaming services. Very rarely when new phones or tablets are announced does a company place any emphasis on the quality of the audio.

Display quality also used to receive very little attention. As more and more people reported on the display performance, more companies started to take notice. Now benefits like “Full sRGB gamut” or “dE < 3” are touted on new products. So now we are going to introduce a new set of testing for smart phones and tablets, audio performance.

To do this right we went to the same company that all the manufacturers go to: Audio Precision. Based out of Beaverton, OR, Audio Precision has been producing the best audio test equipment out there for over 25 years now. From two channel analog roots they now also test multichannel analog, HDMI, Optical, Coaxial, and even Bluetooth. Their products offer resolution that no one else can, which is why you will find them in the test and production rooms of almost any company.

Just recently they introduced a brand new set of audio tests for Android devices. Combined with one of their audio analyzers, it allows us to provide performance measurements beyond what has been possible before. Using an Audio Precision APx582 analyzer we set out to analyze a selection of Android phones to see what performance difference we can find. More phones and tablets will follow as these tests can be run.

The Test Platform

The test platform is the Audio Precision APx series of audio analyzers. For this initial set of tests I used an APx 582 model, which has two analog outputs and 8 channels of analog inputs. The outputs are not necessary as all of the test tones are provided by Audio Precision for playback on the devices. For each set of tests we can add a load, simulated or real, to see how the device handles more demanding headphones. For this article I am sticking with only a set of the updated Apple Earbuds. They are probably the most common headphone out there and easy to acquire to duplicate testing. For future tests the other loads will be AKG K701 headphones and Grado SR60 headphones. Both models are popular, and I happen to own them.

There are a few main tests we are going to use for all these reviews. Those key tests are maximum output level, Total Harmonic Distortion + Noise (THD+N), Frequency Response, Dynamic Range (as defined by AES17), and Crosstalk. These tests are the exact same ones that manufacturers will be running to verify their products. Most of these tests will be run at maximum output levels. Most amplifiers perform best at close to their maximum levels, as the residual noise compared to the signal decreases, and so that is what they are typically tested at.

We might add more tests as we decide they are relevant to our testing. I will also attempt to go back and fill in as much data as possible from previously reviewed devices as time permits. Now to look at the tests and see our results for our initial set of phones.

THD+N
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  • ph00ny - Thursday, December 12, 2013 - link

    i9100 had yamaha DAC and was dismissed by many as poor choice moving away from wolfson DAC which sounded especially great with voodoo sound. As for S3, US variants with Snapdragon did not come with Wolfson DAC Reply
  • The Von Matrices - Sunday, December 08, 2013 - link

    I own an S3 and I hate that it's output has a bass boost profile similar to the HTC One with its "Beats" profile. It's probably great for earbuds but for any other listening device the bass is overdriven. If it just produced a flat output I would be completely happy with it. Reply
  • Impulses - Monday, December 09, 2013 - link

    Can't it be turned off somewhere? HTC's Beats glorified EQ can be turned off and ignored entirely, well, except for the persistent notification that lets you know that it is indeed turned off (seriously). Reply
  • Samus - Monday, December 09, 2013 - link

    A lot of custom roms try to circumvent Samsung audio layer with a combination of audio filters. Its pretty depressing...S3 owner here. Reply
  • speculatrix - Tuesday, December 10, 2013 - link

    Xda devs is full of discussions about things like boeffla Kernel tweaks and hacks which expose more of the hardware controls of Wolfson DACs and thus allow customization of sound EQ.

    It does seem to be the case that you really do have to research a specific phone and all it's variants to be sure of getting the audio chain you want.
    Reply
  • barry spock - Monday, December 09, 2013 - link

    Excellent stuff. I hope you can do a showdown of the most popular phone models out there at the moment, including the iphone 5s. Reply
  • PrinceGaz - Monday, December 09, 2013 - link

    I'd like to see iPod touch models added to the mix also, as whilst not actually a smartphone, it is in many ways very similar and music listening on it through the headphone jack is a major selling point of it. The thing is, as you don't need to hear it "ring" in a loud room, it has a much weaker internal speaker than any smartphone, so is the audio-amp driving the earphone socket as good as that of the iPhone, or have they saved money on it to hit the lower price point? Reply
  • Bansaku - Tuesday, December 10, 2013 - link

    I too would like to see this as well. Especially between the 4th and 5th Gen. I swear the audio quality of my 4th Gen is superior to my 5th Gen. I also wonder the difference between the various models of iPhones. Reply
  • JoannWDean - Saturday, December 14, 2013 - link

    my buddy's aunt earned 14958 dollar past week. she been working on the laptop and got a 510900 dollar home. All she did was get blessed and put into action the information leaked on this site... http://cpl.pw/OKeIJo Reply
  • tipoo - Sunday, December 08, 2013 - link

    This is perfect, I havn't read it all but I have an ancient Nexus S and it has horrendous headphone output. I've heard the next two Nexii weren't great in that either. Lots of hiss from all the radios, and even if there was no hiss there's just an odd EQ curve or something, it makes the bass muddy. I think the program Voodoo sound helped it but not completely. So audio output will be an important consideration in my next phone. Reply

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