Since our initial turn in testing smartphone audio, I’ve had a lot more time to play with the APx582 from Audio Precision. I’ve also received far more feedback than I ever expected to on this subject. I have made a few changes to the testing method that I’m going to outline along with discussing some of the reasoning behind the changes.

All tests are now run manually instead of automated over USB

For most phones, running over USB and running them manually provide the same results. For a few, the commands sent with adb to adjust volume result in a higher maximum volume than you can select with the volume buttons. This causes results that are not correct for real-world use.

Note that non-Android phone testing will be identical. The test tones can be manually selected and used regardless of platform. I will try to determine why this happens, as there is the potential for other software to also set the volume control too high. I’m most concerned with results that match real-world usage and this does that better.

Using standard dummy loads

Before I used common headphones (Apple earbuds, Grado SR60s, and AKG K701s) as my loads. While more real-world than resistors, they also present more issues. They have a nominal impedance, but their impedance might be low in the bass and high in the midrange. If you only base results off the nominal impedance numbers, you can mis-interpret charts.

Duplicating the results also becomes a challenge. The parts used in headphones can change during production. Someone trying to match up their results to ours may not be able to achieve the same data with what they believe are the same headphones. A resistor has a tolerance as well, but with fewer variables it is easier to interpret the data and replicate the results.

For the dummy loads, I selected 15 Ohm, 33 Ohm, 150 Ohm, and 330 Ohm loads. During testing I load each channel with the same value of resistor. The Audio Precision software calculates the wattage from the resistor and voltage.

Fewer charts

The standard Audio Precision smartphone project produces lots of charts. Seriously: a lot of charts. It is easy to include every chart in there but most often they aren’t needed. Instead I plan to summarize the data into a nice table form and include the charts that are indicative of performance. If a chart shows nothing new or unusual, I likely will not include it. If a new chart helps to explain what is going on, I will include it. So sometimes you will see a chart and sometimes you won’t depending on what it shows.

I will pull almost all charts from the 33 Ohm loads. This is the the closest to real-world earbuds for most people. There are a lot of earbuds that drop down into the 16 ohm range, and you should look at the 15 Ohm results for those. Since this is a harder load to drive you are most likely to see worse results than with easier loads. People using over-ear headphones with impedances in the 150-300 Ohm range should use those results. This is easier to drive, but also is going to output far less power in watts so you need to pay more attention to those numbers.

This first round-up includes the HTC One M8 and the Samsung Galaxy S5. This is also purely objective listening. My time with the phones is usually short and I don’t have the time to offer my subjective opinion on the audio quality. I will leave that up to the original reviewer.

HTC One M8 Audio Testing
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  • lessthanjoey - Monday, June 2, 2014 - link

    Wait, what? What about these imperfections is even audible? Reply
  • zShowtimez - Friday, June 6, 2014 - link

    Plug your phone into a decent mid to high end speaker set up. Its so easy to hear the difference. It's part of the reason i went with my htc one over a galaxy s4

    Similar issue with onboard audio vs a discreet card imo
    Reply
  • Streamlined - Monday, June 2, 2014 - link

    Well, it's official. According to hard data and not just opinion, the HTC One kicks the Galaxy S5's butt. If there is one group in the tech world that purchases inferior hardware due to marketing hype, it's Samsung fans. Reply
  • hero4hire - Tuesday, June 3, 2014 - link

    But just Samsung fans... No other group in the entire world. Nope. Just the Samsung fans. Not a single purchase is bought elsewhere due to hype. Previous comment is not baiting. There is only HTC and Samsung and the best marketing in history is the most beloved and most popular Samsung company. It's official that nobody would try to invoke some other company to compare to the best marketing that is Samsung. No arguments here, Streamlined is 100% wanting to keep us focused on HTC & Samsung. Reply
  • theduckofdeath - Wednesday, June 4, 2014 - link

    Yup, because the camera in the HTC phone is a technical marvel. :) Reply
  • Jimster480 - Tuesday, June 10, 2014 - link

    It actually is. Wait until you take a picture in an almost dark room and it comes out perfect. Or if you are in a pitch black area and you take a picture with the flash and it is 100% clear. or you take a picture in a low light resturant and its clean. Or a pic at a concert and its got mid range lighting at best and its clear aswell! I have found the camera to be great in almost all lighting scenarios. Now it doesn't take as beautiful pictures as my EVO 4G LTE did in bright lighting, but its pretty close, and considering how many other scenarios the camera is useful in, the pro's far outweigh the cons. Reply
  • theduckofdeath - Wednesday, June 11, 2014 - link

    It's an extremely limited camera, made for one of the least common usage scenarios. For everything else, it's far below average. Reply
  • The1Metallian - Friday, June 6, 2014 - link

    I have a GS3 and I'm ready for an upgrade. I would buy the HTC M8 in a heartbeat, but the camera broke the deal. I don't expect the camera to be DSLR quality but at least up to par with any other smartphone in the market. I want to know that wherever I am I will be able to take a good picture if needed. The Sony Experia Z2 won't be subsidized by any provider. What am I left with? (don't say iPhone) If the LG G3 doesn't deliver when released, I'm getting the GS5. Samsung competitors need to get a clue Reply
  • Jimster480 - Tuesday, June 10, 2014 - link

    The camera is actually not bad at all. I'm not sure why everyone hates on it, but it takes great pictures in basically every lighting. And the quality is more than enough for any type of social sharing... Reply
  • gevorg - Tuesday, June 3, 2014 - link

    What about jitter? Reply

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