• 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.











    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
















    Comments 30 Comments
    1. wgscott's Avatar
      wgscott -
      Thanks, Chris. Very helpful review.

      I have two very basic, stupid questions:

      (1) Can it play apple-centric formats like ALAC and AAC?

      (2) Does the DAC sound any better than an internal DAC on a good laptop or iMac? (I use headphones directly into my iMac's headphone analog jack at home sometimes, and find it is surprisingly good.)
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by wgscott View Post
      Thanks, Chris. Very helpful review.

      I have two very basic, stupid questions:

      (1) Can it play apple-centric formats like ALAC and AAC?

      (2) Does the DAC sound any better than an internal DAC on a good laptop or iMac? (I use headphones directly into my iMac's headphone analog jack at home sometimes, and find it is surprisingly good.)
      Hey Bill - It will play ALAC but based on my testing I don't believe it's bit perfect. Haven't tried the lossy AAC but I believe it's supported. No answer for you on the DAC quality.

      Edit: Plex is transcoding ALAC to MP3, so I am unsure what to say now :~)

      Edit 2: Plex is capable of playing ALAC without transcoding. Now I believe the Chromecast Audio doesn't support ALAC without conversion.
    1. jeffmudrick's Avatar
      jeffmudrick -
      Do you have reason to believe the CCA implementation is lacking somehow beyond the 24/96 limitations ? I wonder why it's "not remotely a high end device"?
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      Quote Originally Posted by jeffmudrick View Post
      Do you have reason to believe the CCA implementation is lacking somehow beyond the 24/96 limitations ? I wonder why it's "not remotely a high end device"?
      Hi Jeff - My comments about it not being a high end device have nothing to do with the enjoyment one may receive from this device. I'd take the Chromecast Audio playing my favorite music rather than an ultra high end stereo playing Scottish nose whistle at 32/384 any day. However, it's tough to build a high end device that does what the Chromecast Audio does and sell it for $35. The high end crystal oscillators is many high end devices cost more than the entire Chromecast Audio.

      I am trying to get the Chromecast Audio jitter tested as well.
    1. jeffmudrick's Avatar
      jeffmudrick -
      Quote Originally Posted by The Computer Audiophile View Post
      Hi Jeff - My comments about it not being a high end device have nothing to do with the enjoyment one may receive from this device. I'd take the Chromecast Audio playing my favorite music rather than an ultra high end stereo playing Scottish nose whistle at 32/384 any day. However, it's tough to build a high end device that does what the Chromecast Audio does and sell it for $35. The high end crystal oscillators is many high end devices cost more than the entire Chromecast Audio.

      I am trying to get the Chromecast Audio jitter tested as well.
      Looking forward to your tests. I know I'm spending more time with the Chromecast than my Roon USB setup. I'd love to hear the CCA with the Wyred Remedy.
    1. wgscott's Avatar
      wgscott -
      Quote Originally Posted by The Computer Audiophile View Post
      Scottish nose whistle at 32/384 any day. .
      Obviously, you just haven't heard a good nose whistle.

    1. Toolonginexile's Avatar
      Toolonginexile -
      great review THANKS!. I had put aside my device while waiting for the update as well. A couple of questions.

      1) How do you get to the settings page you provided in order to ensure you have the latest firmware? My settings looks nothing like yours. I only get a list with google apps feed back, privacy etc. There is a version listed as 1.136812, But there is no other page.....

      2) Re Plex Wasnt there some talk that plex automatically down rez's files ? How can you ensure plex is playing back uncompressed?

      I have high hopes for this thing hooked up to a dac but as you mentioned it will not be ready for prime time UNTIL THE FOLKS AT TIDAL get on board.
    1. pmcvicar's Avatar
      pmcvicar -
      This is an excellent follow-up Chris given the drastic changes the latest firmware provides. I'm very interested to hear your impressions of the performance of this device into a good DAC vs alternative streamers.
    1. James Cridland's Avatar
      James Cridland -
      Quote Originally Posted by Toolonginexile View Post
      How do you get to the settings page you provided in order to ensure you have the latest firmware? My settings looks nothing like yours. I only get a list with google apps feed back, privacy etc. There is a version listed as 1.136812, But there is no other page.....
      If you're running Android, you want to use the Chromecast app, and select 'Devices'. Then, choose the menu button (the 'kebab' button, which is three dots above one another), and choose 'Device settings'. The firmware settings are at the bottom of the page.

      As an aside: you should also test Google Play Music, which both allows you to play from any song in its catalog (just like Spotify), but also lets you upload your own tracks to the system, so all your music is in one place. Those uploads are either matched with existing songs, or are, I believe, transcoded.
    1. Cebolla's Avatar
      Cebolla -
      Chris, don't forget to include testing for gapless playback. I've seen mentioned that gapless is only supported when the CCA is streaming from Google Play Music and even then it's been reported that it might not be true gapless, since there may be momentary pauses going unnoticed due to the relatively faster loading and playback of much smaller MP3 files (the only file format currently supported when streaming from Google Play Music).
    1. Bryan's Avatar
      Bryan -
      Nice device for the times especially for younger generations we see everywhere squinting at smartphones screens giggling at whatever inane thing is tickling their fancy. Sarcasm aside, affordable digital music is a good thing.
    1. The Computer Audiophile's Avatar
      The Computer Audiophile -
      I was just reading a bit more about the internal components of the Chromecast Audio on the ifixit site. The site mentioned the model number as RUX-J42. One commenter on the site suggests the following about this model number:


      "RUX-J42 =
      "R U eXperienced", and J-42 was the internal code for Midnight Lightning, a posthumous release from James Marshall Hendrix (aka. Jimi Hendrix). Looks to be a direct Hendrix reference."


      https://www.ifixit.com/Teardown/Chro...Teardown/50189
    1. james45974's Avatar
      james45974 -
      I bought a CCA when it first came out with high hopes but in my opinion Google has not delivered a great user experience. For my low-fi listening use I keep going back to my Sonos system, as the saying goes "it just works"! No fiddling around with another program (Plex) trying to get local content to play, the casting performance was iffy at times. I have a regular ChromeCast hooked up to my TV and find that its performance is better than the CCA.
    1. jeffmudrick's Avatar
      jeffmudrick -
      Quote Originally Posted by james45974 View Post
      I bought a CCA when it first came out with high hopes but in my opinion Google has not delivered a great user experience. For my low-fi listening use I keep going back to my Sonos system, as the saying goes "it just works"! No fiddling around with another program (Plex) trying to get local content to play, the casting performance was iffy at times. I have a regular ChromeCast hooked up to my TV and find that its performance is better than the CCA.
      Thus far the CCA is best suited to streaming services rather than local playback. I expect that will improve. The bugginess with local FLAC playback should get sorted with a firmware update . For those who listen primarily via Google Play Music, Spotify, or Tidal however, well Sonos Shmonos, the CCA is a godsend. It just works too, for $35.
    1. loop7's Avatar
      loop7 -
      32/384

      Hilarious
    1. speavler's Avatar
      speavler -
      Does the Tidal app work the same as the spotify app - 'cast-enabled'?
    1. jeffmudrick's Avatar
      jeffmudrick -
      Quote Originally Posted by speavler View Post
      Does the Tidal app work the same as the spotify app - 'cast-enabled'?
      On Android Tidal streams via BubbleUPnP. Direct integration still forthcoming.
    1. james45974's Avatar
      james45974 -
      Quote Originally Posted by jeffmudrick View Post
      Thus far the CCA is best suited to streaming services rather than local playback. I expect that will improve. The bugginess with local FLAC playback should get sorted with a firmware update . For those who listen primarily via Google Play Music, Spotify, or Tidal however, well Sonos Shmonos, the CCA is a godsend. It just works too, for $35.
      I hope they get the bugs and user experience worked out. The prospect of passing through better than redbook resolution to my DAC as opposed to the capability of Sonos, would be great. It would take my low-fi up a notch! I don't do too much streaming, my house is internet impaired (only satellite or dial up here), but I do use TuneIn and Pandora occasionally. Playing my local content takes precedence, so CCA has a ways to go to have 'It Just Works' status.
    1. jeffmudrick's Avatar
      jeffmudrick -
      Quote Originally Posted by james45974 View Post
      I hope they get the bugs and user experience worked out. The prospect of passing through better than redbook resolution to my DAC as opposed to the capability of Sonos, would be great. It would take my low-fi up a notch! I don't do too much streaming, my house is internet impaired (only satellite or dial up here), but I do use TuneIn and Pandora occasionally. Playing my local content takes precedence, so CCA has a ways to go to have 'It Just Works' status.

      I have no problems with local Redbook FLAC playback using BubbleUPnP (or Shuttle) on mobile. As Chris indicated some hirez works some doesn't. It'll get fixed.
    1. airdronian's Avatar
      airdronian -
      It's an interesting device for sure. Anyone try AIFF files, of any bitrate ?