USB and Digital Music


fi•del•i•ty (fĭ-dĕlˈĭ-tē, fī-)

n. The degree to which an electronic system accurately reproduces the sound or image of its input signal.

The MERCEDES AMG PETRONAS Formula One racing team knows the importance of quality audio communications while in motion. It is no surprise they use BlackBerry technologies to help run their organization. So what does that have to do with USB and Digital Music? Not much. I just wanted to show the picture of Nico Rosberg after his win at the Spanish Grand Prix. Congratulations to Nico, Lewis Hamilton who took 2nd and the BlackBerry sponsored Mercedes AMG Petronas team.

Digital, Analog and why some of us care



Above is a simplified diagram of how some audio flows within a generic phone. As you can see, there are multiple sources of audio content:

  • Voice from the phone, BBM voice/video, Skype, Voice Over IP (VOIP), etc…
  • Music and other sound files such as video, voice note, notification, etc…
  • Streaming audio from Web, podcast, radio app, FM radio (for phones so equipped), BlackBerry Assistant, voice navigation, etc..

It is assumed all audio content is digital. Digital audio is made up of numeric codes which represent the original sound. It is created by taking analog output from a microphone and converting it to digital using an Analog to Digital Converter (ADC). The way those work is outside the scope of this article. Digital audio content is easier to store and transmit and, does not degrade as it is copied and moved around.

When audio content, such as music is converted to and from digital, some information is lost. This is referred to as fidelity loss. The quality of the analog to digital and digital to analog converters makes a difference to how much fidelity loss occurs.

Finally we get to the point of this article

When you playback music from your BlackBerry phone, you have 4 options to hear it:

  1. Phone speakers. While the phone speakers on some models (Z30 and Passport) are excellent, music still sounds better through:
  2. Wired earbuds or headphones
  3. Bluetooth stereo headset or speakers
  4. USB digital audio stream to an external Digital-to-Analog Converter (DAC).

What? You didn’t know your phone outputs a digital music stream from the USB port? While, in truth not all BlackBerry 10 phones have this capability. If the model support USB On The Go, your phone probably can do USB DAC. I tested a Classic and could NOT get it to work.


In order to use the digital audio stream flowing out the USB port, a USB headphone amplifier is needed to convert the digital to analog. Above is the model I have (Fiio-E07K-Portable-Headphone-Amplifier). There are many of these devices with a wide range of price. Not all will work with a phone.

Why use an external DAC when the phone has one built in? The simple answer is fidelity. The DAC in the phone is adequate and a high quality DAC is expensive. Few people are willing to pay more for the phone to get slightly better sound which they probably would not notice anyway. For audiophiles, the fidelity loss within the phone’s DAC is undesirable. We are willing to pay for a higher quality DAC. And, because our phone is capable of sending the pure digital data stream out the USB port, we can take advantage of that higher quality.

Check out the demo below:


The Fiio-E07K will be available later today on the UTB Store!!


jrohland has never been able to figure out how to use Capital letters in his name. He can't write like e.e. cummings but he word rhymes sometimes.