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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  • dylan522p - Sunday, December 08, 2013 - link

    Just because you have a good DAC,doesn't mean you have great audio. S4 has a great DAC but it can't even power high impedence headphones. Reply
  • cjl - Monday, December 09, 2013 - link

    The S4 powers moderately hard to drive headphones just fine - sure, it won't drive something like an HD650 adequately, but the majority of consumer headphones out there will go plenty loud driven straight out of an S4. That having been said, it would be nice if it had a bit more power for hard to drive headphones. Reply
  • oktrav - Monday, December 09, 2013 - link

    I can't believe how many people on the internet are singing this song... Does it really matter who makes the DAC if the output sounds like crap? The DAC is just one of many components that affect the sound quality. You can have the best components in the world and still produce absolutely dreadful sound. Ask any wannabe audiophile who's dabbled in assembling home systems out of separates. This is akin to saying that your car must be very powerful BECAUSE it has Bosch coil packs --and Bosch makes the BEST coil packs (just play along for the sake of the analogy, I'm not actually asserting that Bosch makes the best coils --I don't know). Reply
  • nomopofomo - Sunday, December 08, 2013 - link

    So glad you went into such depth.

    Best case scenario, the public and manufacturer are both made aware of the flaws.
    Reply
  • drwho9437 - Sunday, December 08, 2013 - link

    This has been needed badly for some time. Phones displacing media players this matters a whole lot. To me far more than actually anything else about a phone. Reply
  • probedb - Sunday, December 08, 2013 - link

    You also have to remember with some measurements about what is actually audible and what isn't. It's crazy seeing people moaning about nanoseconds of jitter on DACs yet they're quite happy with milliseconds of the equivalent of jitter on vinyl. Then again some of these companies sell ethernet cable at £1600/m and claim it makes a difference to sound ;) Reply
  • matagyula - Sunday, December 08, 2013 - link

    Great to see something like this on anand!
    I would like to see some older high-end phones compared to the ones we have now - for example the Nokia N900, or maybe even some of the ooold Sony-Ericsson Walkman phones (W810 and up). I'd find such comparison interesting ^^
    Reply
  • chubbypanda - Monday, December 09, 2013 - link

    Great stuff Chris!

    I was also wondering if it's possible to add some ancient phone with cult following from audio geeks. You know, Nokia N91 and similar. According to some, sound quality on the phones were never better, so that'd be nice to see what is really happening.
    Reply
  • wrkingclass_hero - Sunday, December 08, 2013 - link

    So, how long before Arstechnica "discovers" the audio problems with the Nexus 5? Reply
  • crabperson - Sunday, December 08, 2013 - link

    YES! Thank you so much for doing this, its awesome. I didn't realize audio/amp quality was a huge thing until I upgraded my headphones. Being able to hear the difference between the same audio file on two different devices made me realize how little manufacturers care about audio quality.
    Then using an FM transmitter in my car showed me how some devices can't pump out enough power over the headphone jack. My Galaxy Nexus has pretty good audio quality (and does optical audio out through the dock, also awesome) served me fine for pumping up music through the FM transmitter. The Galaxy S3 I'm temporarily using does not though, and produces noticeable clipping at max volume. It also isn't properly shielded and when charging there is interference on the headphone jack (something you should also test if you haven't thought of it). I'm looking at upgrading if I can't fix my Nexus, and hope the HTC One is as good as it in terms of audio quality (with Beats disabled of course).
    Reply

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