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Chromecast Audio

Reply #50
Understood, thanks. So the only thing that the HDR is doing is the louder is better effect on sound quality, at the expense of possible clipping at times. Why Google used the HDR name for this setting is a mystery - I can't see they need to call it that to increase sales.

Chromecast Audio

Reply #51
Why Google used the HDR name for this setting is a mystery - I can't see they need to call it that to increase sales.

It seems like you're confusing compression/limiting for dynamic range.

If the noise floor stays the same and a signal can be played back at a higher amplitude without an increase in distortion on the device  with the setting enabled then it is indeed providing higher dynamic range.  Until measurements are made available, I see no reason to assume the switch doesn't do exactly what the name implies.

Whether or not your content will make use of it is another issue entirely.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Chromecast Audio

Reply #52
It seems like you're confusing compression/limiting for dynamic range.

I was only responding to the comments in post#48 - I still have to hear it in use.

Chromecast Audio

Reply #53
I was only responding to the comments in post#48

Post #48 suggests the HDR setting provides an increase in dynamic range.

Why Google used the HDR name for this setting is a mystery.

There shouldn't be any mystery.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Chromecast Audio

Reply #54
I was only responding to the comments in post#48

Post #48 suggests the HDR setting provides an increase in dynamic range.

Why Google used the HDR name for this setting is a mystery.

There shouldn't be any mystery.

You are saying that the increase in dynamic range would not be seen in the output wave form?

Chromecast Audio

Reply #55
I was only responding to the comments in post#48

Post #48 suggests the HDR setting provides an increase in dynamic range.

Why Google used the HDR name for this setting is a mystery.

There shouldn't be any mystery.

You are saying that the increase in dynamic range would not be seen in the output wave form?


If you take the two waveforms and amplify the weaker signal to the same amplitude as the louder one, they should be identical. However, I did see a little more visible clipping in the HDR signal that I recorded, I'll have to test that some more.

Higher dynamic range simply allows the voltage swing from 0 to be larger, in this case 2V RMS instead of maybe 1.2V or 1.4V RMS (I'm guessing, I don't know the exact output level in non-HDR mode). This can give you a slightly higher signal-to-noise ratio, if your equipment can handle it, but in practice the difference is very small for ordinary playback.

2V RMS is the de facto standard output level from CD players and similar equipment since basically forever, so any even halfway competent amp or receiver should be able to handle it just fine.

I also made the mistake of equating "high dynamic range" with "disable dynamic compression", but when you think about it, the name they chose for the option makes sense.

Chromecast Audio

Reply #56
I also made the mistake of equating "high dynamic range" with "disable dynamic compression", but when you think about it, the name they chose for the option makes sense.

You did however say that compression is visible with the HDR enabled and not visible when the HDR was turned off?

The question really is - if precise level matching - as would obviously be necessary -  was done for a blind AB test, could you say which mode was in use?

Chromecast Audio

Reply #57
I also made the mistake of equating "high dynamic range" with "disable dynamic compression", but when you think about it, the name they chose for the option makes sense.

You did however say that compression is visible with the HDR enabled and not visible when the HDR was turned off?

The question really is - if precise level matching - as would obviously be necessary -  was done for a blind AB test, could you say which mode was in use?


No compression, just a few clipped peaks. I doubt I would be able to successfully ABX the difference.

Chromecast Audio

Reply #58
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.


BubbleUPnP does not support gapless playback on the Chromecast Audio.

The exact Gapless support of the Chromecast Audio is a bit of an unknown even
if Google Music can be played gaplessly to it. Surprising, as mp3 is not inherently a gapless format,
and Google Music mp3 are tagless (no presence of the lame specific headers for gapless).
So whether it would be able to play FLAC gaplessly is a bit unknown although there is
a good chance it can.

EDIT: after verification, Google Music is not gapless: there's a very short 50 or 100ms gap (playing a gapless album of course).
This largely reduces the chance for Chromecast Audio to support true gapless playback (vs just reducing the time it takes to play next track, which
for Google Music is very low).

Chromecast Audio

Reply #59
You are saying that the increase in dynamic range would not be seen in the output wave form?

I said nothing of the sort; rather, I suggested that a proper measurement is in order.

Please review the technical definition of dynamic range; the one that was in place long before the it became confused with dynamic range compression.  If you still think I'm wrong then I'll be happy to discuss it further.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Chromecast Audio

Reply #60
If you take the two waveforms and amplify the weaker signal to the same amplitude as the louder one, they should be identical. However, I did see a little more visible clipping in the HDR signal that I recorded, I'll have to test that some more.

Higher dynamic range simply allows the voltage swing from 0 to be larger, in this case 2V RMS instead of maybe 1.2V or 1.4V RMS (I'm guessing, I don't know the exact output level in non-HDR mode). This can give you a slightly higher signal-to-noise ratio, if your equipment can handle it, but in practice the difference is very small for ordinary playback.

2V RMS is the de facto standard output level from CD players and similar equipment since basically forever, so any even halfway competent amp or receiver should be able to handle it just fine.

I also made the mistake of equating "high dynamic range" with "disable dynamic compression", but when you think about it, the name they chose for the option makes sense.

I suggest you also review the technical definition of DR and then compare it to the technical definition of SNR.  I'm not saying you're entirely wrong, just that the precise term in the situation is DR, not SNR.

Anyway, I thank you for looking into this.  I too had initially thought the HDR setting was a DRC control that was improperly named for marketing reasons.  I was pleasantly surprised to see that they may have gotten it right (assuming higher dynamic range is actually achieved with the setting).  If the switch still doesn't work as advertised then maybe they should have gone with the more traditional line level nomenclature.

This kind of reminds me of the "Dynamic Range" switch on the Marshall Vintage Modern.  When switched from "low" to "high" it inserts a parallel triode gain stage for the sole purpose of providing additional clipping in the preamp.  To this day I still have a hard time wrapping my head around the decision making behind naming this switch.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Chromecast Audio

Reply #61
It really shouldn't be that hard to stream music from a NAS to a stereo without having to spend a fortune. I'm hoping the Chromecast Audio can make the happen, because the other solutions I've tried so far have failed to make it work easily and reliably.

Were you able to do this with CC Audio? Could you explain how, in some detail, if you have?
Thanks!

Chromecast Audio

Reply #62
I suggest you also review the technical definition of DR and then compare it to the technical definition of SNR.  I'm not saying you're entirely wrong, just that the precise term in the situation is DR, not SNR.


I know, and I actually looked it up before posting this time ;-)

My point is simply that a higher DR signal is more resistant to received noise and the base thermal etc. noise floor of any given device, and that can result in a higher SNR. In practice, line level signals are strong enough that it doesn't make that much of a difference, unless you're recording things through multiple steps where the cumulative noise can be a factor.

The most extreme example in general use would be the signal from turntables with MC pickups, where the signal is maybe 0.5mV compared to the common 1V or 2V from less archaic devices, which is of course why turntables are sensitive to signal cable quality and length, and normal line level signals generally aren't, outside of more extreme cases.

So for the Chromecast the option is kinda irrelevant for most people, but useful if you just can't get enough volume out of your setup otherwise. Personally, I prefer having a bit more usable range on the volume knob, so I use the "low" setting.

It really shouldn't be that hard to stream music from a NAS to a stereo without having to spend a fortune. I'm hoping the Chromecast Audio can make the happen, because the other solutions I've tried so far have failed to make it work easily and reliably.

Were you able to do this with CC Audio? Could you explain how, in some detail, if you have?
Thanks!


Yes, it works beautifully. The only issues I've run into seem to be app-specific. For instance, TuneIn tends to lose connection with the Chromecast after a while when the phone screen turns off, and I've managed to get Google Music confused about which track is playing, by spamming requests for next/previous track and play/pause. If you don't do that, there are no issues.

The app I'm using on my phone is BubbleUPNP. As mentioned before, it unfortunately doesn't support replaygain, but it does just about everything else. Maybe Foobar Mobile will turn out to be the best option when it's finished, assuming it will support DLNA and Chromecast.

Chromecast Audio

Reply #63
How stable is music play over wifi using CC? I ask because music stuttering/stopping is a killjoy that will make the CC a non starter in my book.

In 2011 I used Airport Express for some time, but switched platforms to Sonos to address just this. In 4 years, Sonos has provided very stable music play at home using the dedicated to audio SonosNet. It isn't as stable as legacy wired kit of course, but over four years these issues caused by occassional RF interference have been few and have been far outweighed by Sonos convenience and features. And if these too are to be eliminated, there is the admittedly inconvenient option of ethernet wiring the Sonos units to the wifi router. But I haven't felt the need for doing so.

CC does not provide that option, and since interrupted music play will make it a non starter, is why this question.

Chromecast Audio

Reply #64
I haven't had any issues with stuttering, except when all of my Internet bandwidth is being used for other things and I try to stream from Google Play Music or other Internet sources. Local playback from a DLNA server using BubbleUPNP is always fine.

Chromecast Audio

Reply #65
Thanks for that update, and I have also recently come across the neat little optional power supply cable that can now be bought if needed, that allows for the CC to be ethernet wired to the router for such places where the WiFi environment is too noisy/busy. Inconvenient yes, but that may be the only way to get interruption free music in some places.

Chromecast Audio

Reply #66
EDIT: after verification, Google Music is not gapless: there's a very short 50 or 100ms gap (playing a gapless album of course).
This largely reduces the chance for Chromecast Audio to support true gapless playback (vs just reducing the time it takes to play next track, which
for Google Music is very low).


Thanks for that. Chromecast Audio was tempting for me, but not if gapless is impossible.

I recently switched from a WD NAS to a Synology NAS, but I haven't been able to achieve true gapless playback on either over DLNA. The only reliable gapless solution I've found is to play albums over SMB using Neutron.

Chromecast Audio

Reply #67
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.


When using SPDIF optical the wordclock locks into 48k while using the Spotify App via Chromecast. So the Chromecast Audio probably resamples everything to 48k unless Spotify streams are in 48k which would make no sense to me.

Chromecast Audio

Reply #68
If I recall correctly the 48khz thing has been acknowledged as a bug by Google and a fix is reportedly coming in a firmware update.

Chromecast Audio

Reply #69
I'd like to do something pretty simple:

Using an Android tablet or phone and use the Google Play "local" feature to play music from a USB drive located and accessible on our home network.

Cast the result to Chromecast audio which I would hope would also be able to use the same USB drive network accessible file to continue playing when the tablet/phone was put to sleep.

All of the above would be using FLAC encoded files.

Should this work?

Would the result be the same if a Chromecast was used instead of a Chromecast Audio?

Thanks!

Jim

Chromecast Audio

Reply #70
After doing a bunch of reading on Google Play I'm getting the impression that it won't play anything that it hasn't already uploaded.

"Local" appears to mean it downloads it again. I was hoping for a truly local play with no intervening upload/compression/download cycle.

Am I missing something?

Chromecast Audio

Reply #71
For playback of local files, I don't think Google Play Music will work. You'll need something like BubbleUPNP (for DLNA or music directly on the device), or a similar app that supports playback of music on an SMB share and Chromecasting the playback.

Localcast (https://play.google.com/store/apps/details?...lcast&hl=da) seems to be a very popular solution.

Chromecast Audio

Reply #72
It just occurred to me that I didn't put up any kind of proof that the HDR option is a simple line output level switch.

Well, here it is (I had to learn/use Ardour, as Audacity refuses to run for some reason):



It's not precisely sample-aligned, but I think you'll agree that both recordings are identical once amplified to the same peak level, and that there's definitely no compression going on.

And yet reviewers and forums users keep going on about how switching on HDR is an ABSOLUTE MUST for sound quality with the Chromecast Audio. At best, it'll buy you a little more SNR, but that's about it.

Chromecast Audio

Reply #73
And again, if the SNR improves then the switch does indeed provide an increase in dynamic range.  Of course people will continue to erroeously equate it with compression; that just goes with the territory.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Chromecast Audio

Reply #74
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.


Looks like there's a new update for the Chromecast Audio that adds snake oil and cool new features.

Multi-room is here!  You can now stream to multiple Chromecast Audios at once!  Nice!

And they added support for 24/96 "hi-res" audio.  All placebophiles rejoice!

http://chrome.blogspot.com/2015/12/even-mo...-audio.html?m=1

 
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