Chromecast audio - can anyone comment on sound quality?

[markbrauer]

Quote:

 
I can't find this app on the Playstore, are you talking about the Chromecast app? I have no such option in the Chromecast app though.
 

What I'm talking about is the cast function that shows up when you swipe down from the top of an Android screen.
 

 
I believe it is native to the Android as it also shows up on my wife's tablet that DOES NOT have the Chromecast app installed.  But one thing I read indicated that the Chromecast app was needed to activate it. When "turned on" it casts audio to the selected CCA. I assume with a video Chromecast it would cast the screen also. Might be a function of Android version? Or the specific device? Google it.

 

[musicfreak]

  Might be a function of Android version? Or the specific device? Google it.

This function is available from Android 5.0 (lollipop) onwards.

 

[titaniumx3]

When using the cast entire screen (or all audio in this case), does anyone know what the output quality is like? Does it compress the audio (e.g. into AAC) and then stream it? Was hoping it would send it as a PCM 44.1khz stream, but I doubt it very much.

 

[mobbaddict]

  What I'm talking about is the cast function that shows up when you swipe down from the top of an Android screen.

Thank you, I believe it's only in the stock version of Android, but on Touchwiz I have access to this option in the Chromecast app > Cast screen / audio

 

[markbrauer]

  When using the cast entire screen (or all audio in this case), does anyone know what the output quality is like? Does it compress the audio (e.g. into AAC) and then stream it? Was hoping it would send it as a PCM 44.1khz stream, but I doubt it very much.

If The Android casting function is altering the stream in any way I could not hear it.
 
Not a scientific test but, using my Nexus 5 
 - running Android Bubble UPnP as the server (which uses the Android cast) 
 - streaming FLAC and WAV files from my local library 
I was able to compare the sound quality of
 - the optical output from the CCA
 - to the USB output from my Squeezebox Touch (with the Hi-Res Audio mod installed) streaming the exact same files. 
 
My DAC/amp has optical and USB inputs and I was able to instantly switch between them. Streaming 44/16 and 96/24 material I was not able to hear a difference. So it seems to me that the Android cast function is not doing data compression on the stream sent to the CCA.
 
As a side note, when using the audio output from the CCA, files higher than 44/16 do seem to lose something but that would be expected as the CCA is reported to downsample those files to 48/16.
 
The biggest downside of casting directly from your Android device is that it eats battery like crazy. Best to have it on the charger.

 

[Ggroch]

Thank you for the analysis Mark.  Theory is important, understanding compression can be a useful, but actual A/B listening comparisons are the most valuable I think.
I am also sure that others will hear greater differences than you did.
 
 I am also transitioning from a Squeezebox (though without the Hi-Res mod) and have been pleased with the sound quality.  Most of my local music is on high bitrate MP3 files, so while it is not the toughest test, I am quite satisfied with what I hear now through TosLink, a moderately priced DAC, and an unnecessarily large collection sub $500 headphones.
 
I do not agree that "The biggest downside of casting directly from your Android device is that it eats battery like crazy."  I think having calls interrupt the music and notification beeps and buzzes is the biggest downside.    
 
I am using Plex from a desktop most of the time for local files to avoid these problems. I would be surprised if Plex provides the same quality on uncompressed files as Bubble, but it also sounds fine without the cast from phone issues. 

 

[titaniumx3]

  If The Android casting function is altering the stream in any way I could not hear it.
 
Not a scientific test but, using my Nexus 5 
 - running Android Bubble UPnP as the server (which uses the Android cast) 
 - streaming FLAC and WAV files from my local library 
I was able to compare the sound quality of
 - the optical output from the CCA
 - to the USB output from my Squeezebox Touch (with the Hi-Res Audio mod installed) streaming the exact same files. 
 
My DAC/amp has optical and USB inputs and I was able to instantly switch between them. Streaming 44/16 and 96/24 material I was not able to hear a difference. So it seems to me that the Android cast function is not doing data compression on the stream sent to the CCA.
 
As a side note, when using the audio output from the CCA, files higher than 44/16 do seem to lose something but that would be expected as the CCA is reported to downsample those files to 48/16.
 
The biggest downside of casting directly from your Android device is that it eats battery like crazy. Best to have it on the charger.

Thanks. Just to confirm, was your testing done using the cast/mirror function? As in, did you stream music using the "Cast" button on your notification bar (as seen in the picture you posted above)? Or, was it using casting directly from a app such as BubbleUPNP?
 
I know that using something like BubbleUPNP will stream the file directly, i.e. the original audio file is sent to chromecast, which decodes it itself, but I doubt this happens with the cast/mirror function I'm talking about. This function has to send all the sounds made by your android device (e.g. your phone) to the chromecast, which means the device itself would have to decode everything and send it to the chromecast as a single stream. The question is, is that stream something uncompressed such as PCM audio or compressed such as AAC.

 

[yay101]

I know that using something like BubbleUPNP will stream the file directly, i.e. the original audio file is sent to chromecast, which decodes it itself, but I doubt this happens with the cast/mirror function I'm talking about. This function has to send all the sounds made by your android device (e.g. your phone) to the chromecast, which means the device itself would have to decode everything and send it to the chromecast as a single stream. The question is, is that stream something uncompressed such as PCM audio or compressed such as AAC.

FYI the mixer itself will likely do as much damage as any compression used while you are streaming device audio. It will likely be pass through pcm at 16:44 while only one sound is playing, but as soon as multiple hit the mixer will be losing bits all over the place.

Use a network monitor app to work out what you are streaming. I don't have a CCA yet, even my cc2015 is taking forever to get to Australia.

 

[markbrauer]

  Thanks. Just to confirm, was your testing done using the cast/mirror function? As in, did you stream music using the "Cast" button on your notification bar (as seen in the picture you posted above)? Or, was it using casting directly from a app such as BubbleUPNP?
 
I know that using something like BubbleUPNP will stream the file directly, i.e. the original audio file is sent to chromecast, which decodes it itself, but I doubt this happens with the cast/mirror function I'm talking about. This function has to send all the sounds made by your android device (e.g. your phone) to the chromecast, which means the device itself would have to decode everything and send it to the chromecast as a single stream. The question is, is that stream something uncompressed such as PCM audio or compressed such as AAC.

 
I have tried both.
 - using BubbleUPnP to cast the stream directly from another (local) DLNA server and
 - using it to channel everything through the Android, which uses the Android casting function in a cast/mirror fashion. 
To test the second situation I streamed directly from Google Drive so there was no server or music software involved except BubbleUPnP on the Android. I listened for a couple hours this way, playing many favorites, and noticed no problems - except battery drain.
 
I have no way to prove that the stream is the same but listening comparisons sure seem the same. I notice no degradation to sound quality due to data compression, while I definitely do hear differences with other comparisons. I don't doubt that others, with different equipment will report differences.
 
A side note...  I started out with an Android app called LocalCast. In tests it did stream 192/24 files successfully. BubbleUPnP only seems to handle 96/24. Not an issue for me as I only have a few 192/24 demo files. But using LocalCast, the CCA streamed those 192 files just fine. With BubbleUPnP they just don't play.

 

[markbrauer]

  Thank you for the analysis Mark.  Theory is important, understanding compression can be a useful, but actual A/B listening comparisons are the most valuable I think.
I am also sure that others will hear greater differences than you did.
 
 I am also transitioning from a Squeezebox (though without the Hi-Res mod) and have been pleased with the sound quality.  Most of my local music is on high bitrate MP3 files, so while it is not the toughest test, I am quite satisfied with what I hear now through TosLink, a moderately priced DAC, and an unnecessarily large collection sub $500 headphones.
 
I do not agree that "The biggest downside of casting directly from your Android device is that it eats battery like crazy."  I think having calls interrupt the music and notification beeps and buzzes is the biggest downside.    
 
I am using Plex from a desktop most of the time for local files to avoid these problems. I would be surprised if Plex provides the same quality on uncompressed files as Bubble, but it also sounds fine without the cast from phone issues. 

High bitrate MP3s are nothing to be ashamed of. They can sound great. I listen to a lot of Spotify (approximately 320kbps OGG compression) and find it to be near CD quality as advertised. But my main system does pass bit-perfect streaming data to my DAC - no Windows mixer or other stream-altering "pass-through" as most experience.
 
I find the Hi-Res mod for Squeezebox is only incrementally better - but it is better. Triode rules!
 
I guess I don't get that many notifications so I haven't noticed that problem. Kudos to you.
 
I tried Plex a while back for video streaming and abandoned it because it doesn't start on computer boot - a deal-breaker for me as I have multiple users and cannot predict Windows updates/restarts. Googled that problem and tried a "fix" for that - ended up having to rebuild Windows 7 from a restore point. Found another server.

 

[phile1]

hi
i confirm the feedback regarding that casting drains the battery of my smartphone, galaxy note2 in my case.
to solve this point, ans as i listen to web radio and often the same one for long runs i do the following :
1. i launch the cast using TuneIn app
2. i cut the wifi on the phone
3. then as the cast is running as itself i can shut down the app on the phone
4. i put the wifi on back on the phone for standard use
then, casting is running from TuneIn to the CAA thru the web, the phone doesn't interact and battery is ok.

otherwise it is true that battery drain is quite impressive and you nearly need to keep your phone on its charger.
rgds

 

[yay101]

Launch a bug report with tunein developers then, unless the media is physically on your phone OR you are casting local media (from a nas) WITHOUT bubbleupnp server installed on a desktop/ nas machine you shouldn't get battery drain at all.

 

[wersus]

I'm wondering that if I plug Chromecast audio to mic in of my sound card and play microphone sounds trough my speakers, how much it would affect sound quality compared to playing with native Windows player? I want to use my phone as music remote and my sound card is Asus STX II.

 

[brymuse]

Hi
I don't post much, but just received my CCA and hooked it up to the HiFi and really surprised at the quality and am now wondering about using it with a DAC.
How much would you have to spend on a DAC to improve the SQ? Is it good enough that you would need a fairly decent model to hear noticeable differences. I've yet to test it with my HD650s but remember that using a cable to the headamp (without a dac) sounded rather muddy.
Any thoughts/suggestions would be greatly appreciated.

 

[markbrauer]

  I'm wondering that if I plug Chromecast audio to mic in of my sound card and play microphone sounds trough my speakers, how much it would affect sound quality compared to playing with native Windows player? I want to use my phone as music remote and my sound card is Asus STX II.

[color=rgba(0, 0, 0, 0.8)]If you take the audio-output from the CCA and connect to the audio-input of your sound card, realize that your music goes through a D to A conversion and analog stage in the CCA, then an A to D conversion in the sound card, then another D to A conversion and analog stage before being sent to your amp/headphones/speakers. Sound quality is lost in each conversion. This can't be good.[/color][color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)]Conversely, when using the "native" Windows player, the music is run through an internal digital "mixer" which converts all sounds from the computer (music, sounds from any open programs, [/color][color=rgba(0, 0, 0, 0.8)]notification beeps, startup/shutdown sounds, etc.) to a common bit rate and combines them into one stream that is sent to the sound card where it goes through a D to A conversion and analog stage before being sent to your amp/headphones/speakers. Here the big sound quality hit is in the bit rate conversion and mixing steps. This also can't be good.[/color][color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)]With so many factors involved there's be no way to predict which setup would result in higher quality without actually trying them out. Which you could do.[/color][color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)]But...[/color][color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)]If concern is sound quality, I would get an alternate Windows player that can bypass the native Windows audio mixer and have the ability to send "bit perfect" data directly to your sound card for a single D to A conversion and output. Many recommend JRiver or Foobar2000. Both offer remote control via smartphone app.[/color][color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)][/color]
[color=rgba(0, 0, 0, 0.8)]Or if you really feel compelled to use the CCA, get an inexpensive digital optical to coaxial converter that would allow you to connect the digital optical output of the CCA directly to the digital coax input of your sound card for a single D to A conversion and output[/color][color=rgba(0, 0, 0, 0.8)]. This option should maintain high quality sound and also offers the ability to cast anything you can access on your phone to your sound card.[/color]