Audio quality on Android devices

After reading the posts here and elsewhere on the audio quality of iPhone 5, I asked here

http://forums.androidcentral.com/general-news-discussion/322204-audio-quality.html

if any similar assessment had been made of audio quality on Android devices.

Coming up to 200 reads and only one insignificant response!

It would seem that Androidcentral geeks have few or no audiophile members.

Has anyone in this place seen studies on Android audio quality?

If I had to live with the analogue output of my Nexus 7 Tablet I would not be crying buckets: it is very competent.

 

I've just carried out some measurements on the Nexus 7. I've used a 44.1KHz wav file played in the Winamp app. I also tried a 48KHz file and this caused quite large distortion in the higher frequencies (as much as 3% at 10KHz) I presume due to sample-rate conversion.

Noise:

-83dB ref. full output.

Disto into 10K Ohms:

@ 100Hz: 0.003%
@ 1KHz: 0.005%
@ 10KHz: 0.002% (plus some >20KHz stuff around -70dB)

IMD into 10K Ohms:

@ 9+10KHz: 0.015%

 

Thanks. And how do you interpret those data in comparison to the iPhone 5?

What did you subjectively think of the sound?

 

The numbers are comparable, and good overall.
Assuming it's response is within say +/- 1db across the audio range it will sound clean and neutral.

For some perspective, that's far better than the best analogue studio tape machines responsible for much of the music we've collected over the years.

 

And some folk drool over those!

 

It's not perfect though, the noise level is a little high and so is the IMD, but certianly not bad. That little Fio D3 DAC gives a similar performance and they were very popular for a while.

 

Not as good as Apple's offering, then?

It's over a year since I listened. I uploaded my FLAC library to Google Play Music where they reappear as MP3s at 320kb/s. They sounded quite good. Scratching head: I think I transferred a few FLACs to the Nexus 7 and played them direct. My remembered impression is that if I played the FLACs from a PC on Foobar into a Beresford 7510 (the older DAC) and onto the Quad 77 and AVI N4s, they sounded a little better - but not enough to get fussed about - and I might easily have been kidding myself.

Rob's comment about the quality of the DAC in the latest Apple Airport Express has me wondering about a PC/Airfoil/Airport express setup. I would even work with an Android remote control.

http://www.rogueamoeba.com/airfoil/

The £80 Airport express is very good value.

You couldn't buy a second hand Squeezebox for that, and one of the DIY Community Squeeze options would certainly cost more and involve more effort.

http://www.communitysqueeze.org/faq.jsp

 

That's now how I listen when streaming. I have Rega and Cambridge Dacs but use neither as the benefit is too small to worry about. You need a good level matched A/B comparison session and be listening critically for specifics to hear anything between them - and even then it manifests more as tiny difference in presentation rather than quality.

I love the simplicity of just using an iPad as my music source playing straight into the AEX via Airplay. That running a Spotify subscription + the Rega CD player does me just fine.

 

The really poor high frequency performance of the Nexus 7 when doing sample-rate conversion does make me consider the importance of running ones soundcard at the native sample-rate of your main software player / media.

I wonder what Spotify uses for their streamed material. My local files are all 44.1KHz and if Spotify got their data from CDs then that probably is too. They might have got it direct from the record companies archives though which may be 48KHz or higher for all we know.

That said I remember trying to do a distortion test on something a while back and found Windows was doing sample-rate conversion and while it did change the results, it was not bad at all. IIRC it was mostly stuff appearing <-100dB.

 

I had just finished watching a video review of the new Haswell HP 14" Chromebook

http://www.engadget.com/2013/09/11/hp-chromebook-14-with-haswell-hands-on-video/

when your post popped up, Tenson.

I had been listening on headphones so as not to inflict it on my dearest, so I clicked up my Google Play Music account which has my CD collection uploaded. Most will be from Google's own database and only a very few odd ones really uploaded.

They come back to me at 320kb/s MP3.

Nothing wrong with them, listening on the years old small headphones I got years ago with my Sony Pro-Walkman!

It's a while since I listened to Google Play Music on the HiFi - but I USB the Chromebook to by Beresford Caiman DAC. Again, nowt wrong with the results.

NB Chromebooks do not run Android, but Chrome OS - a locked down Linux. ALSA is there in the bowels, but not easy to get at to tinker with.

 

320kb/s doesn't say the sample-rate though only the data-rate. There will still be a native sample-rate for the files and if your hardware is running at a different clock speed it will need conversion in software.

 

Agreed.

The 44.1 - 48Kb/s fiasco in XP and the soundcards used at the time was one of the reasons I went to Squeezebox.

I don't know, but I am supposing the Google database of CDs keeps them all at 44.1, but I don't know.

 

Just USBed the Chromebook running Google Play Music to my Beresford Caiman DAC.

I compared the sound of a 320kb's MP3 to it's parent FLAC streamed from a Windows 7 PC to a Squeezebox Classic and on to the Caiman DAC by Toslink. I know that chain is not re-sampling. If Google is, I cannot hear a problem, and yes Google has reduced the FLAC to an MP3 at 320kb/s.

I usually stream the FLACs - it's so easy.

 

That's all that matters. I suspect the Nexus 7 does a bad job either because of limited CPU power to do on the fly conversion or perhaps the Android Winamp app just doesn't expect the quality matters very much on a portable device. I suspect 3% thd at 10KHz could well be audible on a reasonable system.

 

To play the same tracks from Google Play Music into the Quad 520 I would have to mess about with some wires. I have no analogue input on my system and the Nexus 7 has no USB out!

So not now!

It would be interesting to see what you can measure if you upload one of your CDs to Google Play Music and play it back through the Nexus 7.

As you suggest, Winamp might be doing nasty things.

There is a VLC Beta for Android - It wasn't up to much when I looked - but that was a few months ago.

 

I have copied the FLAC folders of four of my CDs (which are the other side of Europe) to my Nexus 7 from my W7 box - it runs BBC iPlayer into the TV and hosts Logitech Media Server for the Squeezeboxes.

VLC will play the FLACs straight from the Nexus SSD. They sound fine on headphones. I now have to find the right lead and connect the headphone out to the Quad 520f, which has pots on the input.

Edit:

Of course on the Nexus 7 I can also call Google Play Music and compare the locally stored FLAC to the MP3 streamed from the cloud.

I hear no difference. I have swapped to some full size Sennheiser phones, and I running with the volume right up.

 

Found the 3.5mm jack to phono lead so now I am listening to the Nexus 7 driving the Quad 520f directly into the MB Quarts.

Very good. Nothing to complain about and nothing to choose between the locally stored FLACs played by VLC beta for Android and the Google Play Music App streaming from the cloud at 320kb/s MP3.

The problem I do notice is that the Nexus 7 has to run flat out to drive my Sennheiser headphones; it's just OK.