Basic Bit Perfect Testing Of The $35 Chromecast Audio

At the end of September Google released its Chromecast Audio device. The device is simply a WiFi connected digital to analog or digital to digital converter that supports Google's Cast protocol and streaming music directly from Spotify and other cast-enabled apps/services. The Chromecast Audio is distinguished from the original Chromecast and generation two Chromecast by its lack of HDMI output and lack of video support. I ordered a Chromecast Audio as soon as Google announced it, and of course opted for the fastest shipping method available at nearly the same price as the device itself. For $35 I was excited, as was the Computer Audiophile Community. I set my expectations low and hoped for the best. When the unit arrived I plugged it into my system for some straight forward testing. I wanted to know if the device passed the digital audio unaltered. After about three seconds I concluded the Chromecast Audio, in its current state, was a failure. All audio was converted to 48 kHz no matter what sample rate was sent to the device. I put the Chromecast Audio on the shelf and waited to see if Google cared to make firmware changes enabling audio to pass through unaltered. To my surprise, in December Google released a firmware update that not only enabled audio to pass through the Chromecast Audio unaltered, but also enabled support for sample rates up through 24 bit / 96 kHz. It was time to retest and hopefully write a little about the successes or failures.[PRBREAK][/PRBREAK]

Testing The Chromecast Audio

My Chromecast Audio is connected to an 802.11ac network on the 5GHz band. I'm using the stock 5V 1A power supply included with the unit. I am much less interested in its DAC capabilities, so I only tested the unit's digital to digital conversion via the 3.5 mm mini-TosLink output (cable not included). The all-important firmware version is 1.17a.49061.

My first test was to stream Spotify to see if the audio was no longer converted from 44.1 kHz to 48 kHz. This was a success. Spotify streams at the correct sample rate of 44.1 kHz. For those unfamiliar with how Spotify works as a cast-enabled application here is a quicker than quick explanation. The Spotify app on an Android or iOS device is used to select music for playback and to select the output device, in this case a Chromecast Audio. Upon selection of music for playback the music is streamed directly from Spotify's servers to the Chromecast Audio device. This is very different from Apple's AirPlay because AirPlay currently streams audio from Spotify to the iOS device then on to the audio playback device. AirPlay uses the iOS device to route music through it and requires the iOS device to be in a certain state to continue playback (and continues to eat battery life of the iOS device). Using Spotify with the Chromecast Audio, the user can even turn off the Android or iOS device once music is selected for playback. The Android or iOS device is simply a remote control. Just as your television doesn't stop playing video when you change batteries in your remote control, Spotify and the Chromecast Audio don't stop playing audio based on the state of the Android or iOS device.

Spotify = Success

I moved on to testing my local lossless library stored on a NAS. There are several ways to go about streaming local music to a Chromecast Audio device, as evidenced by the discussions in the forums and elsewhere online. I elected to use Plex media server because it offers what I consider to be the best design for what I believe is the most popular way to use a Chromecast Audio device. Plex can run on a NAS or a regular computer, it offers a remote control app and a host of other features. Don't get me wrong, the other ways of streaming a local collection or Qobuz streaming are great, but I focussed on Plex as I believe it's the best option for most people.

The first tests with local music identified a major issue with the Chromecast Audio. I tried basic 16/44.1 music and couldn't get anything to play. I searched forums for hours and tried several "fixes" to get it working but nothing resolved the issue. In my frustration I tried a higher resolution file and it played! Thus, I started looking at my files and discovered the Chromecast Audio doesn't work well with uncompressed FLAC files created with dBpoweramp and some additional dBpoweramp levels of compression. More on the issues below.

• 16/44.1 FLAC uncompressed bitrate 1412 ripped from CD with dBpoweramp wouldn't play
  
• 16/44.1 WAV bitrate 1411 converted from FLAC uncompressed with dBpoweramp plays bit perfect
  
• 16/44.1 FLAC Compression Level 0 bitrate 926 converted from FLAC uncompressed with dBpoweramp plays bit perfect
  

16 bit / 44.1 kHz = Success

• 24/88.2 WAV bitrate 4233 is resampled to 48 kHz by Chromecast Audio
  
• 24/88.2 WAV bitrate 4233 resampled from original WAV with JRiver is converted to 48 kHz by Chromecast Audio
  
• 24/88.2 FLAC uncompressed bitrate 4240 converted from original WAV with XLD plays bit perfect
  
• 24/88.2 FLAC Compression Level 0 bitrate 2760 converted from WAV with dBpoweramp wouldn't play
  
• 24/88.2 FLAC Compression Level 0 bitrate 2766 converted from WAV with JRiver plays bit perfect
  
• 24/88.2 FLAC Compression Level 1 bitrate 2748 converted from WAV with dBpoweramp wouldn't play
  

24 bit / 88.2 kHz = Success

• 24/96 WAV bitrate 4608 converted from FLAC uncompressed with dBpoweramp is resampled to 48 kHz by Chromecast Audio
  
• 24/96 WAV bitrate 4608 converted from FLAC uncompressed with JRiver is resampled to 48 kHz by Chromecast Audio
  
• 24/96 FLAC uncompressed bitrate 4609 converted with dBpoweramp wouldn't play
  
• 24/96 FLAC uncompressed bitrate 4615 converted from (non-playing) FLAC uncompressed with XLD plays bit perfect
  
• 24/96 WAV bitrate 4608 converted from FLAC uncompressed with XLD wouldn't play
  
• 24/96 FLAC Compression Level 0 bitrate 2754 converted from FLAC uncompressed with dBpoweramp wouldn't play
  
• 24/96 FLAC Compression Level 5 bitrate 2590 converted from FLAC uncompressed with dBpoweramp plays bit perfect
  
• 24/96 FLAC Compression Level 0 bitrate 2761 converted from FLAC uncompressed with JRiver plays bit perfect
  

24 bit / 96 kHz = Success

Google hasn't announced support for sample rates higher than 24/96, but I wanted to test higher rates while I was at it, just to see if they would play. In my testing 24/176.4 and 24/192 wouldn't play and caused the Chromecast Audio to stop working with Plex until it was reselected as the output device.

24 bit / 176.4 kHz = Fail

24 bit / 192 kHz = Fail

Conclusion

The Chromecast Audio is a really cool, $35, simple device. It's not high end by any stretch of the imagination, but it's not meant to be high end. In addition to testing, I listened to the Chromecast Audio a little bit and think it sounds like a good $35 audio device. Most people on the planet will be 100% satisfied with the sound quality. In addition, people who believe bits are bits and all digital audio must sound the same will be incredibly pleased with the Chromecast Audio. It's capable of bit perfect playback from 16/44.1 through 24/96. My testing revealed that the device can be picky when it comes to supported file formats. Some FLACs play perfect while others don't. I'm certainly not going to convert my entire 60,000 track library to a specific level of FLAC compression with a specific encoding application in order to play the files on the Chromecast Audio, but people who libraries are already in the supported format should be happy. The real sweet spot for Chromecast Audio, in my opinion and experience, is playback with streaming services like Spotify. There's nothing to configure and nothing to worry about. It just works. Now, if Tidal would get on the ball and cast-enable its app, all would be good in the world. Happy new year everybody!

Purchase a Chromecast Audio -> LINK

Chromecast Audio forum discussion -> LINK