Airplay & downsampling

Hi All,

I think, I can bring some clarity/facts to this issue now :-) - since I own(ed) the relevant devices and actually TESTED this ...

Setup:

- Apple MB Pro (OS: Mac OS X & Windows 7) - iTunes-"Server"

- Apple TV 2, connected via TosLinke to ...

- ... Musical Fidelity M1 DAC (which ist limited to 24/96 via TosLink connection)

- Amp Creek Audio Evolution 5350 --> PlayBack...

(1) Unfortunately: NO. AppleTV 2 is NOT capable of streaming Hi-Res (24/96 oder 24/192) Files (in any format) from your Computer/iTunes library to your D/A Converter via AirPlay. Since the M1 DAC shows the "incoming" sample rate, you can see, ATV2 ALWAYS send at 48 kHz - no matter what sample rate / BitRate your source files are (in other words: ATV2 WILL stream the data, but not in the correct *lossless* format).

--> this is, why I already returned this device "back to sender" ;-(

(2) MB Pro IS capable of providing a "real" 24/96 connection via TosLink (optical cable) and a DIRECT connection to the DAC (and I feel the sound is "crispier" this way - just sounds that bit better than streamed via AirPlay). And, BTW, this is fact for OS X as well as Win 7.

(3) Since I now need a different solution (I have a lot of HiRes stuff in my iTunes library), I'll also return the (very good sounding!) M1 DAC and buy a "Marantz NA7004" Network Player with integrated AirPlay ability.

--> I've already read in a forum, THIS device WILL stream audio-content via AirPlay up to 24/192(!).

--> As soon as I get the device I will keep you informed ... (anybody still interested in this?).

Hope this helped some of you ...

Best regards

Hi CurlyMC,

do you already own the "Marantz NA7004" Network-Streamer(?)

I am still in the "experimental" phase ... and did not yet find a solution that provides 24/96 (24/192) via AirPlay - ATV2 for sure does NOT (I tested this --> it's limited to 24 Bit/48 kHz).

Will the NA7004 fulfil my needs(?) - some (on the internet) say, it will(?)

Thanks for your answer :-)

B.

Finally ...

I got hand on an "Marantz NA 7004" with AirPlay today and ...

... Jesus, what a disappointment!!!

The sound quality of this device is WAY inferior (in any setting!) than with my actual system (ATV2 & Musical Fidelity M1 DAC) - worst of all are the integrated "FM/AM" as well as "DAB+" tuners(!) These sound so lame ... Oh My God!!!

I also streamed via AirPlay (24/96 is shown as such on the display of the device - if it's actually streaming this format I cannot say, but I assume so). Nevertheless: also here the resulting audio is a SHAME compared to the solution ATV2 (with 48 kHz!) + M1 DAC.

So my conclusion: keep your hand off that Marantz NA 7004 device - it's performance is just disappointing(!)

Can't imaginge, why the testers (stereoplay/audio etc.) rate this piece of rubbish that high! I would rate it 4-5 of 10 ... (just because of the great flexibility it offers - sound quality is 4 of 10 - worst device ever connected to my system!).

If you don't belive me .... try for yourself...

CU

Blendax74 wrote:

I am still in the "experimental" phase ... and did not yet find a solution that provides 24/96 (24/192) via AirPlay - ATV2 for sure does NOT (I tested this --> it's limited to 24 Bit/48 kHz).

Are you sure that ATV2 can handle up to 24/48 and not just 16/48? I know iTunes and other AirPlay enabled devices can play 24-bit audio files via ATV2, but I suspect that they truncate them to 16-bit for playback. Unfortunately, my amp doesn't tell me whether it's receiving 16- or 24-bit audio, so if someone can confirm this it would be very helpful.

Presumably the next version of ATV may be able to handle higher bit and sample rates via AirTunes, assuming the specification supports it (I'd be surprised if it didn't), along with true 1080p video. Let's hope so anyway.

Thanks,

Keith.

I use a Pioneer VSX-1021 which is capable of playing sound files up to 24bit/192kHz. Two things I'd like to share with you:

• When I stream a 24bit ALAC to the device [over Airplay] it shows 16Bit on the Pioneer
• But I can't tell if iTunes or the Pioneer does the downsampling. The VSX-1021 won't play a 24bit FLAC from USB, but its okay if streamed for example. So I dont know who to blame.

bye

Mathias

Thanks Mathias. My guess would be that it’s almost certainly iTunes that’s doing the downsampling. Whilst the AirPlay protocol seems theoretically capable of handling any combination of sample sizes and rates, current devices only support streaming of 16/44.1 or 16/48, even if their native quality is higher, so perhaps this is a limitation of iTunes.

Does anyone have any evidence that an Apple TV or AirPort Express is streaming more than 16 bit or 48kHz audio? It seems like something that Apple could add without too much difficulty given that they already support higher bit rates for 5.1 surround and DTS.

I have the same receiver, Mathias, and use Airplay all the time too. Where does it tell you what the sampling rate is - on the receiver's screen? Mine doesn't show me the bitrate or the the khz rating anywhere that I can tell. I'd be curious to see if this is ever upgraded, too. If only airplay was a non-proprietary protocol, we'd be able to track it a lot easier.

heiseheise wrote:

Where does it tell you what the sampling rate is - on the receiver's screen?

It's not shown on the receiver's display or the receiver's VideoOut, at least I never found out how. Information like this you can only see on Pioneer's proprietary iOs app iControlAV2... 😠

And I would love some AirPlay diagnostics application...

The NA7004:

- Airplay streaming with 24/96 aiff shows 1411kbps, so i assume that's downsampled to 16/48 (actual bitrate is 46xx kbps)

- Same file, SPDIF output from imac (with midi settings to highest): NA7004 shows 96khz, and i hear the difference.

- Music server: doesn't play the file at all

So 'playability' of hi-res files could be a lot better, especially on an audiophile brand like marantz.

As mentioned above: DAB tuner is very ok to me.

Hello,

I have a Denon AVR-4311 (which plays HD Flac at 24bit 96kHz and accepts 24bit 96kHz through DLNA) and asked this question to Denon UK directly since I never found a clear answer on the web.

This is the answer i received:

"Apple AirPlay always plays files @ 16bit 44.1 KHz regardless of their sampling frequency"

So I guess this question has been answered.

"Apple AirPlay always plays files @ 16bit 44.1 KHz regardless of their sampling frequency"

That can't be right since Apple TV only outputs 16-bit, 48KHz audio. But it since nobody has been able to find evidence of AirPlay using higher sample sizes or frequencies, and quite a few evidence to the contrary, I guess you are right that the answer re. HD audio playback is in the negative. This seems to be a limitation of existing devices rather than AirPlay specification itself though, so I hope we can look forward to improvements in this area soon.

- Keith

Has anyone tested the HDMI audio output of the Apple TV 2?

To challenge the idea that iTunes is responsible for the downsampling: what happens in the event that a 24b/48kHz ALAC file existing on an iPhone 4S is streamed via Airplay to an Apple TV 2?

Is the file actually downsampled to 16 bit? This abovementioned scenario is common for me, so I am keen to know if downsampling occurs, but if it does, I would hazard a guess that it's the Apple TV doing the downsampling.

I am also interested in another common scenario:

If you use the Apple TV's menu to play 24b/48kHz files that exist in the iTunes library of a Mac elsewhere on a *wired* network, would the be downsampled to 16 bit?

Given the rumours of Apple considering moving their iTunes Music Store content to 24 bit, it seems strange that *any* of their devices would downsample to 16 bit, especially the Apple TV, which is most likely to be connected to hi-fi equipment via a digital connection.

There is talk on the Web that the iPad2 can output hi-res files via the Camera Connector Kit to a USB DAC. My own experience with the Nuforce uDac2 is that this capability is intermittent. ALAC files up to 44.1 play fine but higher sample-rate files transcoded from FLAC are not working. These same hi-res play back perfectly from my iMac USB port into the uDac.

Check out this announcement from Benchmark about their success with hi-res using their DAC:

http://www.benchmarkmedia.com/discuss/feedback/newsletter/2011/06/1/ipad-streams -high-resolution-audio-dac1

Very interesting.

Referring to the article, I'm assuming that when they talk about Home Sharing via the iPad, they are streaming 24b/96kHz ALAC files that are stored on their MacBook, though they don't explicitly state this anywhere.

Unfortunately, the AppleTV's hardware is older than the iPad 2 (A4 vs A5 processor), so no parallels can easily be drawn. On the flipside, the iPhone 4S shares similar hardware to the iPad 2, which makes me wonder if it performs similarly to Benchmark's tests.

EDIT: @Vin Gizzi -- when you say "higher sample-rate files transcoded from FLAC are not working", do you mean to say that you are attempting to play FLAC files stored somewhere on your home network, via your iPad 2 over wifi, using some kind of alternate media player (like StreamToMe)? Or do you mean you have converted FLAC to ALAC (using XLD or Auditri) before attempting to play them?