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  • rajas
  • [*]
Chromecast Audio
Reply #25
https://www.ifixit.com/Teardown/Chromecast+...+Teardown/50189

Here's the iFixit teardown. The DAC is an AKM AK4430 192kHz 24-Bit Stereo DAC. I assume it should be fairly transparent.

  • KozmoNaut
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Chromecast Audio
Reply #26
Yeah, I don't really see how anyone can reasonable argue against the quality of that DAC chip, not even the high-res delusionists.

Or maybe they can. It doesn't do DSD, after all...

dynamic range compression


Don't the record labels do this for us already?  :-)


Yeah, they do. Maybe it's something to do with the output levels, too. The AKM DAC can do full 2V RMS output, maybe cheap portable speakers can't handle that, since they're designed for smartphones and other devices that put out significantly less power.

It'll be easy to test whether the overall output level is also lowered when compression is enabled.
  • Last Edit: 07 October, 2015, 04:07:50 PM by KozmoNaut

  • andy o
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Chromecast Audio
Reply #27
A bought a Voyager Edge bluetooth headset that support "HD Voice (Wideband Audio)" and that doesn't cut it for me.

The phone/device shoud also have wideband audio support, specifically HFP 1.6. I don't think HD audio is mandatory in that profile, but that profile seems to be what brings support for it. Pretty sure all current and relatively old iOS devices support it, but on Android support is sketchier. I know the Nexus 6 does, but something as recent as the Nexus 5 doesn't. I'm not sure if the app also has to support it, with Skype for instance I got much clearer audio on the iPad mini 2 than on my Nexus 6, with the same Sony headset, but that can be due to other things.

  • andy o
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Chromecast Audio
Reply #28
I got one of these a few days ago. It's doing pretty good, and it's freed one of my scarce HDMI ports in my old-ish AVR from the old Chromecast which besides the audio part, it was being redundant for video duties, since I also got a PS3 which has better Netflix and an HTPC which has better everything else.

I think the device mirroring function is not so much like Bluetooth, but more like Airplay. They should make it easier though to set it up, with something like WiFi Direct or just use the WiFi network that the Chromecast creates for setup, for outdoor use or otherwise where there's not a WiFi network available. I assume it would work with just a WLAN with no internet, but that's cumbersome. This should be ideal for those scenarios since Android now supports being connected to an internet-less WiFi network while still connected to mobile internet.

BTW, multiroom support is coming in a firmware update "later in the year".
  • Last Edit: 08 October, 2015, 04:32:26 PM by andy o

  • bawjaws
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Chromecast Audio
Reply #29
What would really be nice is if you could have multiple chromecast audios and they all can stay in sync.  So, if you have one in the living room and dining room and one set of speakers don't sound like they're a little off from the other pair.  Cheap whole house audio would be pretty nice.


They've been talking about this feature for a while (apparently demo'ing to people working on chromecast apps), I was assuming it would be announced with the launch of the new device, but instead they just said it would be available "later this year".

edit: should really read all the comments before replying, to save repeating stuff that's already been said.
  • Last Edit: 08 October, 2015, 06:28:30 PM by bawjaws

Chromecast Audio
Reply #30
A bought a Voyager Edge bluetooth headset that support "HD Voice (Wideband Audio)" and that doesn't cut it for me.

The phone/device shoud also have wideband audio support, specifically HFP 1.6. I don't think HD audio is mandatory in that profile, but that profile seems to be what brings support for it. Pretty sure all current and relatively old iOS devices support it, but on Android support is sketchier. I know the Nexus 6 does, but something as recent as the Nexus 5 doesn't. I'm not sure if the app also has to support it, with Skype for instance I got much clearer audio on the iPad mini 2 than on my Nexus 6, with the same Sony headset, but that can be due to other things.


From the research I did last night, Wideband Audio is not a feature of bluetooth, it's a feature of the phone and the carrier.  I'm in the US, and the only carrier supporting Wideband Audio is Sprint.  AT&T is planning to support it in the future, and Verizon has no plans whatsoever.  Meanwhile, the rest of the planet has wideband audio everywhere...  Sigh...
  • Last Edit: 09 October, 2015, 11:13:29 AM by apastuszak

Chromecast Audio
Reply #31
I got one of these a few days ago. It's doing pretty good, and it's freed one of my scarce HDMI ports in my old-ish AVR from the old Chromecast which besides the audio part, it was being redundant for video duties, since I also got a PS3 which has better Netflix and an HTPC which has better everything else.

I think the device mirroring function is not so much like Bluetooth, but more like Airplay. They should make it easier though to set it up, with something like WiFi Direct or just use the WiFi network that the Chromecast creates for setup, for outdoor use or otherwise where there's not a WiFi network available. I assume it would work with just a WLAN with no internet, but that's cumbersome. This should be ideal for those scenarios since Android now supports being connected to an internet-less WiFi network while still connected to mobile internet.

BTW, multiroom support is coming in a firmware update "later in the year".


If they nail multi-room support that would be awesome.  If I was Sonos, I'd be real nervous right now.  Here's hoping multi-room support doesn't require their router.

  • andy o
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Chromecast Audio
Reply #32
From the research I did last night, Wideband Audio is not a feature of bluetooth, it's a feature of the phone and the carrier.  I'm in the US, and the only carrier supporting Wideband Audio is Sprint.  AT&T is planning to support it in the future, and Verizon has no plans whatsoever.  Meanwhile, the rest of the planet has wideband audio everywhere...  Sigh...

They're two separate things, actually. If your carrier doesn't offer wideband audio then you won't see much benefit from BT wideband on carrier calls. Sprint is not the only one though, Verizon and t-mobile also offer it on compatible phones, but I think they only work within network. It comes with VoLTE.

But that's not the only way to take advantage of BT wideband, pretty much all VoIP apps use wideband codecs so you'll hear a benefit in Skype, Hangouts, Viber, etc.
  • Last Edit: 09 October, 2015, 05:08:32 PM by andy o

  • andy o
  • [*][*][*][*][*]
Chromecast Audio
Reply #33
Does anyone know how Cast for Audio works when doing audio mirroring? For instance, Airplay streams all audio losslessly through ALAC to be decoded in the Airport Express. I presume it's different than sending audio with screen casting with a regular video Chromecast, since I think this applies lossy compression and possibly low-ish bitrate. I've read at Android Police that the Chromecast video sends noticeably poorer audio than the Chromecast Audio (and I presume other Cast for Audio thingies), but they aren't exactly audio reviewers. From a quick comparison with the old Chromecast and Chromecast Audio, I couldn't really tell any super noticeable differences.

  • audiophool
  • [*][*][*]
Chromecast Audio
Reply #34
^^^ I think it depends on the sender and receiver app. The Chromecast supports WAV (EDIT: and FLAC, see link below). So it's possible to stream lossless audio.

EDIT: Supported Media for Google Cast
  • Last Edit: 10 October, 2015, 06:56:04 AM by audiophool

  • andy o
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Chromecast Audio
Reply #35
I'm talking about mirroring though. Besides "casting" from the cloud, you can also do screencasting with the Chromecast,, and with the Chromecast Audio, audio mirroring, which would be functionally the same as Airplay. Lossless would be welcome to cast from apps that don't support the Chromecast natively or if there's no internet available, avoiding a second lossy compression. (Though I'm not sure if the Chromecast would do mirroring without internet.)

  • audiophool
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Chromecast Audio
Reply #36
I'm talking about mirroring though.

Yes, I'm aware of apps such as AllCast or BubbleUpnp. From what I understand, it doesn't matter whether you stream music from, say, Spotify or mirror the audio playing on your phone. In both cases, apps can make use of the media player library provided by Google. What I was referring to in the previous post is that the library supports WAV and FLAC.

So, if the apps you run make use of Google's library functionality, lossless transfer is doable. But, once again, it depends on the apps, as apps are not required to use Google's library. You know, it's conceivable in theory that an app transcodes any audio stream to lossy WMA initially and passes that on to the Chromecast.

Quote
(Though I'm not sure if the Chromecast would do mirroring without internet.)

I think I've read that the Chromecast doesn't work without an internet connection. I believe that may present a difficulty when trying to install a Chromecast Audio in a car. But I can't say for sure, I haven't tried using a Chromecast without internet access...
  • Last Edit: 10 October, 2015, 10:41:57 AM by audiophool

  • greynol
  • [*][*][*][*][*]
  • Global Moderator
Chromecast Audio
Reply #37
Speaking of cars, I stream music to my car stereo using Bluetooth and do not have problems with the audio that are anywhere near the extent earlier implied by apastuszak.
Regarding mirroring, is chromecast audio capable of streaming phone calls?
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Chromecast Audio
Reply #38
Speaking of cars, I stream music to my car stereo using Bluetooth and do not have problems with the audio that are anywhere near the extent earlier implied by apastuszak.
Regarding mirroring, is chromecast audio capable of streaming phone calls?


I have no issues streaming music at all.  With music I can't tell a difference.  Well, I think I might be able to, but since I can't ABX it, I refuse to admit to there being a difference.  If it even exists, it would be so slight that it would not even be noticeable without serious critical listening, which takes away from enjoyment.

It's only spoken word (podcasts, audiobooks, and phone calls) where I am hearing a difference.  With podcasts and audiobooks, it's not too bad, because we're over A2DP.  I do listen to these things at 1.5x speed with pitch correction.  But I do rip my audiobooks to 128K.  I have older rips I made at 32kbps (back when storage space was at a premium), and I have trouble understanding some words at times over bluetooth.  But now you're looking at 32K MP3 + Bluetooth compression.  That may just be too much compression to keep the spoken word clear to my ears.

But Bluetooth phone is less than ideal.  I'm sure it's a combination of the lack of Wideband Audio in the US, along with the compression Bluetooth does on top of that.  American, British and Canadian accents are fine.  Soon as anyone with an Indian or Russian accent joins, I'm screwed.  Which is odd, because I grew up my whole life with 2 parents with Ukrainian accents, and spent 8 years in grade school with Indian kids with incredibly thick accents.  I'm used to both those accents and can understand them just fine in person.

Chromecast Audio
Reply #39
From the research I did last night, Wideband Audio is not a feature of bluetooth, it's a feature of the phone and the carrier.  I'm in the US, and the only carrier supporting Wideband Audio is Sprint.  AT&T is planning to support it in the future, and Verizon has no plans whatsoever.  Meanwhile, the rest of the planet has wideband audio everywhere...  Sigh...

They're two separate things, actually. If your carrier doesn't offer wideband audio then you won't see much benefit from BT wideband on carrier calls. Sprint is not the only one though, Verizon and t-mobile also offer it on compatible phones, but I think they only work within network. It comes with VoLTE.

But that's not the only way to take advantage of BT wideband, pretty much all VoIP apps use wideband codecs so you'll hear a benefit in Skype, Hangouts, Viber, etc.


I think I am going to try a Hangouts call on my iPhone for my next conference call.  I'll need to do it at home over wifi, since VoIP violates Verizon's TOS on their LTE network.

I'll be happy when VoLTE gets here.  It's not in my area yet.

  • andy o
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Chromecast Audio
Reply #40
Speaking of cars, I stream music to my car stereo using Bluetooth and do not have problems with the audio that are anywhere near the extent earlier implied by apastuszak.
Regarding mirroring, is chromecast audio capable of streaming phone calls?

As far as I understood, he was talking about he hands-free or headset profile, which non-wideband cuts off at lower than 4kHz (at 8kHz sampling). Wideband audio in HFP 1.6 doubles that, the audio calls are much clearer, provided that your carrier also provides "HD Voice", and usually the person you're speaking to also has to have the ability, and be in the same carrier. Or, you can use a VoIP app that supports wideband audio which is all of them pretty much.

Regarding Chromecast, it can't do audio calls, and even if it did, the lag would be too much.
  • Last Edit: 11 October, 2015, 04:19:25 AM by andy o

  • andy o
  • [*][*][*][*][*]
Chromecast Audio
Reply #41
I think I am going to try a Hangouts call on my iPhone for my next conference call.  I'll need to do it at home over wifi, since VoIP violates Verizon's TOS on their LTE network.

That sounds ridiculous even for Verizon, I'm pretty sure you can use any VoIP app, are they blocking the protocol or something? Imagine the outrage if that were true just from iOS users unable to use Facetime. IIRC AT&T tried something like that in the early Facetime days but that was a long time ago and everyone was pissed off.

BTW, only calls within Hangouts are "wideband". Voice calls between Hangouts and regular phones are regular phone quality.
  • Last Edit: 11 October, 2015, 04:25:56 AM by andy o

  • andy o
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Chromecast Audio
Reply #42
I'm talking about mirroring though.

Yes, I'm aware of apps such as AllCast or BubbleUpnp.

Android has native mirroring since Lollipop, though, those apps aren't needed anymore for mirroring to Chromecast, at least.

Quote
From what I understand, it doesn't matter whether you stream music from, say, Spotify or mirror the audio playing on your phone. In both cases, apps can make use of the media player library provided by Google. What I was referring to in the previous post is that the library supports WAV and FLAC.

So, if the apps you run make use of Google's library functionality, lossless transfer is doable. But, once again, it depends on the apps, as apps are not required to use Google's library. You know, it's conceivable in theory that an app transcodes any audio stream to lossy WMA initially and passes that on to the Chromecast.

That's my question though, how does it work. Does it mix and compress all audio to be sent to Chromecast/Chromecast Audio, like Airplay does, or...?

Also, bear in mind that mirroring regular video Chromecast and audio mirroring with "Google Cast for Audio" may be different, that's what I was also wondering, if they are, how are they different?

  • andy o
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Chromecast Audio
Reply #43
OK, after getting home and testing I can add a few observations. Internet-less screencasting and mirroring work within the LAN, if there is no mobile internet, so you can't use mobile internet while screen/audio mirroring from the phone. I don't know if this is a limitation of Android (6.0 on Nexus 6), or a bug that doesn't let the phone communicate with the LAN and mobile internet simultaneously. This would make it very crappy for car use, for instance, even though just by having to set up a WLAN in the car it would be very cumbersome in the first place even if it worked well.

Also, I have a network monitoring app, and while mirroring to Chromecast Audio, the upload throughput stays pretty steadily at 160kbps, even if there is no audio playing. I think the device just mirrors and outputs audio at that bitrate, who knows which codec though.

  • KozmoNaut
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Chromecast Audio
Reply #44
I've been playing around with my new Chromecasts for about a day now, and unlike the DLNA renderer devices I had before, the Chromecasts are rock solid and play everything I've thrown at them so far through BubbleUPNP. Google Play Music also works flawlessly, as you'd expect.

Half the price of the cheapest DLNA device I had before, and the Chromecast actually works.

Even if Party Mode never becomes a reality, I'm very satisfied.

  • 2Bdecided
  • [*][*][*][*][*]
  • Developer
Chromecast Audio
Reply #45
Gapless from BubbeUPnP? If yes, what are you using for a server?

Thanks,
David.
  • Last Edit: 12 October, 2015, 07:18:42 AM by 2Bdecided

  • KozmoNaut
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Chromecast Audio
Reply #46
Unfortunately, I do not have gapless playback using BubbleUPNP, probably due to the NAS I'm using. It's a ZyXel NSA 310 provided with custom firmware for cloud backup by my ISP. So maybe the OEM firmware (or an alternative) will work.

  • KozmoNaut
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Chromecast Audio
Reply #47
I've been playing around with my new Chromecast Audios some more, and I've come to the conclusion that High Dynamic Range should be switched off in the Chromecast app for the majority of setups. From what I can tell, it does not do any dynamic range compression, it is simply a function to switch the Chromecast into full-power 2V RMS output mode, as opposed to a slightly weaker signal (1.4V RMS?) that is safer for equipment of unknown capability.

So unless you're not getting enough volume from your Chromecast'ed speakers, don't touch that setting. There may be a tiny SNR benefit to using the stronger signal, but that's kinda irrelevant when 90% of your volume dial is unusable because it's just way too fucking loud.

I've recorded some music off my stereo while playing the same song with HDR on/off. Aside from the obvious level difference, the waveforms are the same when amplified to 0dB peak amplitude. There is even a hint of compression in in the track I recorded with HDR on, which points in the direction of a tiny bit of clipping due to overloading. I don't know whether that's down to my system or the Chromecast, but I don't think it's my system since the NAD preamp I use accepts up to 10V RMS input. The waveform *looks* better with HDR off, for what that's worth.

Of course, turning HDR on is widely touted as the #1 most important thing to do for sound quality when setting up a Chromecast Audio, because people are making the same mistaken assumption that I was, about dynamic range compression.

It is literally nothing more than a level boost.
  • Last Edit: 13 October, 2015, 02:40:33 PM by KozmoNaut

  • KumarK
  • [*][*][*]
Chromecast Audio
Reply #48
It is literally nothing more than a level boost.

I have one on order for using with a legacy 2 channel amp, that worked fine with 2V output level CDP.

On the other hand, some amps can clip with that level of signal, so a level cut may help.

I suppose the way to select this is to see what gives a more usable range for the combined volume controls - the one on the app and the one on the amp?

  • KozmoNaut
  • [*][*][*][*][*]
Chromecast Audio
Reply #49
My preamp etc. also works just fine with the 2V RMS output from my DAC and various CD players etc., which could mean that the Chromecast can't quite output a 100% clean 2V signal.

Either way, selecting the lower setting gives me more usable range on the volume control, which is nice.