Smartphone wired audio/DACs... (2020 update)

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Despite Apple's (and then Google's) attempts to quosh the humble wired 3.5mm audio jack on modern smartphones (and copied by many others), plenty of decent smartphones are still sold with jacks and with DACs feeding whatever wired headphones you care to plug in. Potentially higher quality, and certainly no issues with drained batteries or lost AirPods (etc.) In this update of an article from 18 months ago, I test some of the 'jacked up' smartphones that I've had in for testing in 2020. Any conclusions, any winners?

Lumia 950 XL and Veho Z-8

As ever, writing about audio isn't trivial, since your ears can't be here to try things and comment with me. So I'll have to run through some of my methodology before launching into actual tests.

A few basics though. I'm testing wired audio here, usually through a 3.5mm socket in the phone but I also threw in a dongle or two, since that's a valid 'last resort' way to go (and the only wired way for iPhones).

In each case, the smartphone's music application (or video, etc.) takes a digital music source (whether local or streaming) and uses the Digital to Analog Conversion (DAC) capabilities of the phone's hardware (either in the main chipset or as a standalone sub-system or perhaps in a DAC dongle) to produce 'analog' voltages, for left and right channels and with a common ground. Leaving aside microphone complications, these analog voltages are turned into tiny speaker movements in your chosen headphones and - hopefully - you hear music in your ears.

And if that seems complicated enough, there are plenty of other variables:

  • The digital source might be compromised, e.g. low bitrate or a poor codec, or simply a poor original (e.g. off vinyl) when the source was created.
     
  • The headphones used are very important, since 99% of the wired headphones I see used out in public are pretty ropey. For example, use some cheap outer-ear headphones (e.g. Apple wired in-box white headphones, or clones thereof) or even cheap in-ear headphones (again, often provided in the box) and you'll be missing many audio frequencies (bass and high end), in addition to also hearing noise 'pollution' from the world around you.
     
  • Your own hearing may be compromised, either through age or over-exposure to loud sounds or music(!)

Now, there's not much that can be done for the last point, but I can certainly address the first two (and you should too), in selecting my test material and equipment. I tried to pick from a range of music genres, settling on, all at 320kbps MP3:

  • Kari Jobe's 'Majestic' live album, track "Hands to the Heavens" - the production on this is superb and there's plenty of bass and high end to test.
  • Take That's "Reach out", from their Beautiful World album - again exemplary production and a full range of frequencies to listen for.
  • "Vierne: Messe solenelle op. 16: Kyrie" from Cathedrale Notre-Dame De Paris - I was there and know how a full choir and organ in that amazing place should sound!

I did my listening through my much-loved and much-used Veho Z-8 over-ear studio headphones - they sound fantastic and as I write this (by coincidence!) are currently on offer on Amazon UK, at £28. Just saying. These were originally over £50. Here's my Z-8 review from back in the day. I know, I know, audiophiles are going to say that I needed to use £200+ headphones as my reference, but I trust these Z-8 and have lived with them for several years. I also tested with my (equally loved but smaller) Marshall Major II, which work in wired mode (here) and Bluetooth if needed (e.g. when exercising). The Major II are now hard to get, but I see the Marshall Major III are now only £57 on Amazon UK. Bargain.

And so on with the testing. Obviously, you're not here with me to listen yourselves (and doing a video or audio sample wouldn't help, since you'd then be at the mercy of the audio capabilities of however you watched/listened), so you'll have to rely on my scoring. Hey, it's all only a guide and I'm more interested in the relative differences, i.e which phones/DACs are better and by what margin?

Finally, I can only report on what I have to hand. You'll have to infer audio quality from related hardware. I do give some idea below - manufacturers usually re-use the same chipsets and (of course) music and video applications across their ranges. The list just constitutes data points. All marks are out of 10.

And, this being AAWP, I'll start with some Windows-powered phones, and then follow with other candidates, including some from this year:

3.5mm-equipped phone
(or DAC)
Similar to§ (if any), and notes Perceived
volume+
Bass++ High end* Separation
/Fidelity**
Total
Lumia 950 XL Same as for Lumia 950 9 9 10 9 37
Alcatel IDOL 4 Pro Still one of my favourite media devices of the last decade 10 10 10 10 40
Wileyfox Pro Never produced in huge numbers, but had the distinction of being the last Windows phone officially sold 7 8 8 9 32
Lumia 930 Same as for Lumia 1520 10 10 9 9 38
Samsung Galaxy S9+ (2018) Same audio as S9, Note 8/9, S10, S10+, S10e (newer Samsungs have no 3.5mm jack) 9 9 9 9 36
Moto G8 Plus (2019) Similar to G8 7 9 8 9 33
Apple iPhone SE (2016) Similar to iPhone 6, 6s, 6s Plus, the last iPhones with a 3.5mm jack 9 8 8 9 34
Sony Xperia 5 ii (2020) Similar to Xperia 1 ii  8 9 10 9 36
Marshall London (2016) The classic Android music phone, now sadly outdated. TWO 3.5mm jacks though! 10 10 10 10 40
Google Pixel 3a XL (2019) Similar to Pixel 3a 8 8 8 32
Google Pixel 4a 5G (2020) Similar to Pixel 4a 8 8 8 8 32
Xiaomi Redmi Note 9 (2020) Similar to POCO X3 NFC and many other sub-£300 Xiaomis 7 9 9 8 33
Planet Computers Cosmo (2019) Similar to Gemini PDA 10 9 8 6*** 33
F(x)tec Pro1 (2020)   10 8 8 7 33
Google DAC dongle
(new version, 2018-)
as used on Pixel 2 and 3 series
and other Type C devices
9 10 9 9 37
Apple DAC dongle (2016-) the only way to get wired audio from modern iPhones 10 9 8 8 35
HIDIZS Sonata HD II (2019-) third party DAC dongle 11(!) 10 10 10 41

Notes:
All phones were tested with 'flat' EQ, i.e. testing default output. Most smartphones (including the Lumias here) have an extra software Equaliser than can be applied to some (or all) output, but these are just software EQ effects and muddy the testing waters too much. This is analagous to me testing phone cameras on 'auto' and not in a 'pro' mode, where things get exponentially more difficult to compare.
§  By which I mean other phone models which will sound the same, usually because they're sister devices in a range.
+  Different DACs put out different amounts of 'oomph'. A decent audio amplifier will easily drive headphones with 'volume to spare', while on lesser chipsets you'll be at maximum volume on the phone and no headroom to increase it further. For example, the Alcatel IDOL 4 Pro puts out so much volume in my headphones at 23/30 while
++  I'm listening for rendering bass right down to 20Hz and lower - I like to hear bass guitar notes in their natural entirety, as if I'm standing by the bass amp (I play guitar and bass) and hearing the subtleties. Most headsets fall down here, providing insufficient (or software-boosted) bass.
*  I'm listening for details in voices and percussion, with no compression artefacts - again, as if I was in front of the singers or percussion, hearing them 'live'.
**  Poor smartphone audio often results in weak stereo separation, with too much common ground between channels. I'm also rating here for an overall impression of fidelity. And, yes, enjoyment.
*** Marked down because of horrible static on the jack when music isn't playing. Clearly electronic issues in the design (and that's not counting Planet wiring the stereo speakers out of phase - gah!)

Verdict

What became apparent, somewhat surprisingly, is that music output and enjoyment on smartphones is less about absolute audio rendering, i.e. less about how well the full range of frequencies could be output for a given audio source (though there are differences), and more about sheer volume/voltage. We've all been there - in a noisy city street and trying to really enjoy our music and even at a phone's maximum output it's only just loud enough. This is where the best music phones have volume to spare. (And no, I'm not going down the 'loud music will damage your hearing' route - I'm assuming that you're being sensible and not overdoing it or for too long a sustained period.)

Most phones in 2020 don't ship with dedicated DACs or power amps - they rely on the DAC in the main SoC (System on a Chip), i.e. audio rendering is now included at 'good enough' levels in the Snapdragon/Mediatek processor so there's no perceived need to have extra audio chips. As a result, many of the scores from 2020 smartphones are similar. At 33 points above, they're not spectacular though - audio is designed for the man in the street listening to the Top 40 'tunes'. Anyone wanting to hear music properly needs to look further. To a smartphone with better DAC (many LG 'Quad DAC'-equipped flagships from 2015-2019 qualify here and would score with the IDOL 4 Pro, though I don't have a suitable LG to hand to test here), or to plug in a Lightning or Type C DAC/dongle.

The IDOL 4 Pro, my favourite Windows 10 Mobile phone, and the music-specialist (and now sadly obsolete) Marshall London, running Android, came top, both with dedicated music chips/amplifiers and some serious output. Along with the Sonata HD II DAC, which still stuns. Plus any of the Lumias from back in the day - Nokia and then Microsoft knew how to put together a smartphone (it's not just imaging). Sigh.

I was also surprised that the Type C DAC-dongle tested, £12 or so from Google, also performed so well. It would be easy to dismiss such tiny electronic components, but they can work very well. Obviously, all such dongles aren't created equal (the HTC one is awful), but it's good to know that if we do end up going down a jackless, Type C-only route, that wired audio quality doesn't have to suffer, even if we do have to put up with extra bits of wire and plastic hanging off our phones. And the Apple one isn't far behind, surprisingly good for its modest £10 purchase price.

Given a phone with decent volume output then, the bottlenecks in terms of wired quality will be the capabilities of the headphones being used, which is why I've reviewed many such over the years, plus the quality of the source material - low bitrate 'pop-grade' MP3s definitely don't 'cut it'. Still, interesting data points, I think, and your comments most definitely welcome.

PS. Of note in 2020 is that Bluetooth 5 is now established and wireless audio is good enough, see the aforementioned Marshall offering, plus my various assorted reviews here on AAWP: