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Sony has always been synonymous with music and so when it comes to audio on our smartphones we have a clear aim to capture the spirit and soul of the music as the artist originally intended. To achieve this we put a number of features in our smartphones; alongside Hi-Res Audio and Digital Noise Cancelling, Xperia Z5 features DSEE HX™ but what does that really mean and how does it make you music sound better? We asked Audio Engineer, Kenichi Matsumoto, to take us behind the acronym and to give us a bit more insight into Xperia Z5’s audio offering.

1. What does DSEE HX™ stand for and what does it do?

Firstly it’ll help if we explain the challenges we face when storing and playing music on a smartphone. The beat of a drum, the vibration of a guitar string or the human voice all produce analogue waves – reaching us as minute changes in air pressure that our brains decipher as musical sounds. Storing that plucked string or vocal performance digitally forces a compromise on us. Those tiny fluctuations of a musical waveform don’t lend themselves to being captured perfectly as a string of ones and zeros in a computer hard drive, memory stick or mobile phone.

This compromise is seen with CDs but is particularly prevalent in MP3 files, where the data has been compressed to enable it to fit in a small file that we can share, stream or download.

In an MP3 or CD, delicate high frequencies often sound harsh, mushy or just plain missing. Bass lacks the true depth and sonority of the original recording. So we needed to do something that meant we rescued these sounds, returning music to the artist’s intention. Of course, the advent of Hi-Resolution Audio is a great evolution to solve this problem. However, it requires several times the disk space of CD. And the music lineup of this great audio format is limited compared to CD or mp3 at the moment. Therefore, we had the further need to do something for existing CD and mp3 music. We had already developed DSEE technology (Digital Sound Enhancement Engine) – a signal processing technology which converted compressed sound such as MP3s to CD-quality sound by recreating the high frequency signal lost when compressing files. We were sure we could actually surpass CD quality by extending DSEE technology so since then we have created DSEE HX™ to enable a near Hi-Resolution Audio experience. The technology converts both compressed sound and CD-quality sound (uncompressed or lossless 44.1kHz/16bit) to near Hi-Res quality Sony-hi-Res_logo-433sound by recreating higher frequency signals and finer signals ( sampling frequency up to 96kHz and bit depth up to 24bit if you’re a details person).

DSEE and DSEE HX’s completion is not a simple up-conversion/up-scaling process. It is Sony’s original technology, based on the analysis results of a number of sound sources, to estimate and complement the signal coming through.

2. In what ways would we notice a difference in sound quality with DSEE HX™ enabled versus listening to a standard MP3 music file?

The best way to compare is to listen with DSEE HX™ switched on and then off using a a compressed sound source like an MP3. The easiest way to do this is to:

  1. Prepare a compressed sound source like an MP3 on your Xperia device. (Live music makes it particularly easy to notice a difference.
  2. Listen to the music source with DSEE HX™ off.)
  3. Stop the playback and switch DSEE HX™ on.
  4. Listen to the same part of that source with DSEE HX™ on. Do not switch DSEE HX™ on / off while listening to the source!

You’ll be able to notice the difference most obviously in the areas below:

  • Expansion and depth of the sound field, or in the size of the performance area (such as in large concert halls compared to studios) – you can feel it with the applause of an audience, afterglow of instruments or atmosphere.
  • Clarity of the position and separation of each instrument
  • Vividness or presence of the performance

Xperia Z5 Group BackYou’re better able to imagine and feel the experience of a performance in its original space. You don’t need to focus on specific instruments or sound. You can just relax and enjoy the whole piece of music.

One of our development engineers explains it as below:

“24bit depth allows you to reproduce faint sound like a reverberation of the vocal that couldn’t be expressed in 16bit. Live sounds often have random fluctuations that convey the atmosphere in the concert hall. DSEE HX™ can grasp even those fluctuations and recover the original data, so you would feel the expansion of the sound field with natural presence.”

3. Does DSEE HX™ affect the size of audio files? And if not, why not?

DSEE HX™ doesn’t affect the file size since it’s processing the temporary streaming data on the operation memory as you listen to them. It doesn’t processing affect the original file.

4. What other Sony devices can you find DSEE HX™ technology in?

We aim to build a consistent audio experience and always try to apply our most up-to-date sound technology on all Sony devices. That means besides Xperia Z series (Z3 or later), the technology can be found in Hi-Res models of Walkman, 4K BRAVIA, AV receiver, our wireless speakers, and a number of other home audio products.

Play Your Music Library in Near Hi Res Audio with Sony DSEE HX™ Sony UK5. Does the software work differently across devices, for example in Xperia Z5 and ZX2 High-Resolution Walkman®?

Although it’s largely similar there is one main difference. After conversion by DSEE HX™ the sampling frequency is different between Walkman (ZX2, ZX100) and Xperia (Z3-Z5). The sampling frequency (Fs) of Walkman (ZX1, ZX2, ZX100, A10, A20) is 192kHz (Reproducibility of the signal is up to 96kHz) whereas the sampling frequency of Xperia (Z3-Z5) (Fs) is 96kHz. (Reproducibility of the signal is up to 48kHz). This is the major difference between the two devices, other than that we’re able to incorporate the same technology in both.

Look out next month as we again go behind the acronym with another of the world’s leading smartphone engineers. Let us know what feature you’d like us to put under the lens in the comments or by getting in touch on Twitter.