Smartphone Audio Quality Testing
by Chris Heinonen on December 8, 2013 5:15 PM EST- Posted in
- Smartphones
- Audio
- Mobile
- Tablets
- Testing
Right now we have full data on four phones and partial data on a few more. We are working to compile as much data as possible to provide an overall look at the quality of audio from smartphones available today. The largest difference in current models is the power of the headphone output as some are much better equipped to drive more demanding headphones than others. As we compile data on more and more products we hope to see more differences arise.
We also have not seen much difference with different loads applied to the headphones. We will continue to test all three sets of headphones but the data here is for the Apple Earbuds. If different loads provide different results, then we will certainly report those different numbers in the future. It also appears that running Android phones in the automated routine causes the 20 kHz tone to be left out of the frequency response test. Humans usually can't hear this, I certainly can't, and so there isn't a huge amount of real-world ramification to this. It causes the reported THD+N to exclude that tone and provides a better result that phones that play it back. For the future, this will be done manually.
Here are the four phones we currently have, and more phones are being tested and reported on as quickly as possible to be added here.
Facebook
Twitter
RSS
188 Comments
View All Comments
Impulses - Monday, December 9, 2013 - link
Ehh, impedance curves for the headphones he suggested (Grado SR80, AKG K701) are easy to find (Inner Fidelity and others have decent databases)... Testing and providing output impedance for the phones would be very valuable indeed though, even if everything else in the chain performs alright that alone can affect the FR significantly with one pair of headphones and not at all with the next... And unfortunately there's never been a realistic standard for output impedance, (other than high quality solid state amps now aiming for >1 ohm), and it's often all over the place.ssddaydream - Monday, December 9, 2013 - link
I agree with this.I think of three main usage scenarios regarding the headphone output:
1.) Quality of HP output driving a high-impedance line-level input for a home or car stereo.
2.) Quality of HP output driving low-impedance, sensitive IEMs.
3.) Quality of HP output driving high-impedance, non-sensitive cans.
For #2 and #3, the output impedance should be known, as well as the amplifier power at a given THD level.
There reasons why the iPhones are able to perform well with IEMs, namely low noise floor and low output impedance. Also, iPhones perform well with larger cans because of the decent output power.
I think the usage cases I listed above are pretty common, so I think a good approach to testing is to think about the most important parameters for each usage case.
BTW, I am excited about AT doing these measurements- very good news, indeed!
Anand_user123 - Monday, December 9, 2013 - link
I use my phone most of the time as a music player. Audio quality and storage capacity for flac files are major factors in my buying decision. I hope we can have more widespread information on smartphones audio performancestepz - Monday, December 9, 2013 - link
If you actually cared about scientific measurements of audio performance you would use compressed audio instead of flac. ;) Given a decent amount of bitrate, compressed audio is indistinguishable from uncompressed in double blind tests. In my experience FLAC is mostly about the listener feeling good about getting the "correct" experience, like expensive speaker cables.Impulses - Monday, December 9, 2013 - link
There's a valid usage case for FLAC as far as ripping and archiving IMO, you might as well if you're ripping a large collection (or ripping often)... Since you can quickly re-transcode or edit files w/o a loss of quality... But yeah, I don't see why anyone would put FLAC files on a phone, transcoding is dead simple and super quick if you have a remotely modern PC. Managing FLAC & MP3 playlists or whatever shouldn't be a hurdle if you're putting the effort to maintain a FLAC library to begin with, just use the MP3 library for everything or use stuff like Media Monkey's smart filters/playlists.NaterGator - Monday, December 9, 2013 - link
The biasing of the amplifier in the Nexus 5 and LG G2 left channel appears incorrect. Note it is only clipping on the negative portion of the waveform.vshah - Monday, December 9, 2013 - link
Can't wait to see htc one results!jrs77 - Monday, December 9, 2013 - link
Could you compare the phones to an iPod maybe? This way we would've an comparisooon to a mediaplayer where there's no 3G/4G/LTE disturbance.Oh, and for the general audience discussing the DACs etc... The DAC isn't the cruicial part, never has been. The amp is what it's all about and how good or poor it's powered.
There's a reason why audiophiles still use tube-amps, or atleast digital amps with high quality toroidal transformers and good shielding to reduce noise distortion etc.
Oh, and btw... A good mediaplayer needs a microSDHC-slot or the possibility to use an USB-stick. A mediaplyer is no good if I can't carry my whole music-library with it (100+ GB).
Leezhunjin - Monday, December 9, 2013 - link
Hi Chris, very nice to see smartphones getting measured in terms of audio performance, as many of these phones are used as a music device as well. Personally, I think that an inclusion of output impedance measurements would really great be though, as it is one of the factors that would affect the earphone performance rather significantly.CSMR - Monday, December 9, 2013 - link
Very good start. Poor quality needs to be exposed and you've done this with the Nexus 5.I would like to see output impedance since low output impedance is a very important quality of a good headphone output.