I’m new to AirPlay, and just today finished getting Volumio with AirPlay set up on a little Cubox. No issues getting my RoonServer to recognize it as an endpoint… so the Cubox (attached to my DAC) quickly started playing Roon served music without a hitch. Except that I’m curious to see that the little round dot on my iPad Roon app - the one that indicates signal quality during playback - is now green. But it’s playing 44.1 kHz / 16 bit material, which I thought was supposed to be supported over AirPlay, no re-sampling needed.
Shouldn’t the little dot be purple, to indicate bit-perfect playback? What am I missing?
Can you post a screenshot of the signal path window?
Sure Brian. Thanks for looking into this…
WFIW I’m a bit red/green color blind myself, and detecting the color of that tiny dot is challenging. But - luckily for me - my wife’s got an art degree, and I’ve gotten a reliable confirmation that the dot is indeed green. Not purple.
Wonderful post on the color-blindness issue here.
To provide a bit more detail… I’ve got RoonServer on a NUC, with a wired e-net connection to the house network. Music being pulled off a wired NAS, when not playing Tidal. The track in my picture should have been pulled from my NAS, as it’s in my FLAC collection. The RoonServer NUC is on the same switch as my Cubox-I (running Volumio with Airplay), which is plugged (USB), into my DAC. I typically have a Jitterbug and Schiit Wyrd in the chain between the Cubox, but I removed them to confirm the green dot without them, before posting my query.
It looks like we always consider AirPlay to be “High Quality” as opposed to “Lossless”. Thinking back, I remember why.
There are two reasons for this:
- Many popular AirPlay devices perform internal format conversions that we know to be destructive (example: all AppleTV models convert 44.1k->48k).
- Since AirPlay streams are clocked at the source, they must either have fancy adjustable clock hardware that can conform to the stream coming from Roon, or they must perform DSP to resolve the clock discrepancy.
This second issue is slightly subtle. It’s our understanding that the vast majority AirPlay devices do not have the fancy clock chip that would be required for them to be truly bit-perfect, and instead modify the digital audio stream internally to resolve clocking discrepancies.
The AirPlay protocol gives us no way to know whether or not devices are committing either of these sins, so we’ve erred on the side of not attaching a false sense of sound quality to AirPlay devices as a whole.
Outstanding reply. Thank you Brian.
Personally IMO everything you’ve stated makes perfect sense. Good call (IMO) in “downgrading” the dot from purple, though - depending on a lot of “ifs” - it may actually be bit perfect, as I suspect it is for me. Certainly sounds good.
Thankfully this all goes away when your RoonSpeaker spec/code is out there soon, and those of us that are so inclined, can all dump airplay altogether.
Thank you very much for the clarification.