Apple TV 4 Audio Pass-Through

I have a fairly “complete” and quite high end AV HT system with the Krell Foundation as the brains, or at the epicenter of the system. It handles very little audio processing from external boxes like ATV or Roku but DOES of course get involved in musical processing. I am able to control this in the musical domain by sending a superb signal to the Krell via my Mac Mini using High Rez audio files that my PS Audio DAC converts first from PCM to single bit DSD and THEN to analog out to my Krell. My Foundation is a gorgeous sounding pre-pro but it will never DEGRADE a better original source signal to a lesser one. Point is I have software attached to my iTunes that plays high res digital music files hrather thsn iTunes) in 96/24 up to 192 or even 384/24 bit. Bottom line your receiver or preamp ought to PASS THROUGH what your source component outputs.

I find that the ATV actually does an EXCELLENT job outputting high current audio. Test it yourself by switching from broadcast TV to ATV. You should get far more gain via ATV and need to turn the volume down a little to a lot. if not something likely wrong. If you select “Dolby 5.1 in your ATV Settings you should always get your receiver to pass through 5.1 Dolby IF the content was made in Dolby. YouTube of course will be delivered only in PCM as Apple chose not to embrace their codec for the App. My LG OLED outputs beautiful Dolby 5.1 using YouTube but Apple not alone here. Roku also fails to support YouTube in Dolby which *****. So it’s garbage in garbage out. You can’t make Lemon out of lemonade. :-).

Concusion: it’s almost ALWAYS about the content and the ability of the source component to express it to the best of your receiver’s ability. Or at least in theory it SHOULD be. Receiver or pre-pro should just pass through and send to your amp. I do agree that Apple could provide for more customization but that’s not the Apple way, right? An interesting test for you might be to try connecting the ATV directly to the TV to bypass the receiver and connect an optical or toslink cable (for audio) from your TV to your receiver/pre and program it to reflect this change. That might do it for you.

Good luck,

It used to normally send PCM for music/stereo video and the DD bitstream for 5.1, ATV 4 also support 7.1- I've assumed AppleTV 4 does this but have moved for a few months and do not have it connected to my Pioneer AV amp just to the Samsung TV.

AppleTV does not support DTS officially, definitely not for iTunes Store content as it's not an option, but I don;t know about 3rd party apps that might stream 'other video' from local shares.

Most users who enjoy high quality audio have the same setup as you do. That's why we have expensive A/V receivers to decode HD multi-channel audio and send it out to our speaker systems. I was so disappointed in Apple to see that they still haven't provided an audio pass-through option in setup with the latest TVOS. To have no option but to have the Apple TV process audio, is a joke. This will always result in inferior audio except for 2-channel sources. I have never seen any worthy audio/video device that does net provide this option. To think the excuse is possibly that it is more difficult to mute non-PMC audio when Siri is invoked, is also a joke.

We need to put as much pressure on Apple as possible to get this fixed!

sailermon wrote:

Most users who enjoy high quality audio have the same setup as you do. That's why we have expensive A/V receivers to decode HD multi-channel audio and send it out to our speaker systems. I was so disappointed in Apple to see that they still haven't provided an audio pass-through option in setup with the latest TVOS. To have no option but to have the Apple TV process audio, is a joke. This will always result in inferior audio except for 2-channel sources. I have never seen any worthy audio/video device that does net provide this option. To think the excuse is possibly that it is more difficult to mute non-PMC audio when Siri is invoked, is also a joke.

We need to put as much pressure on Apple as possible to get this fixed!

Can you clarify - It should not really matter if AppleTv is decoding and outputting PCM or handing on a bitstream to be decoded.

Perhaps you mean that an AV amp would reduce effects of jitter and could potentially upsample internally, but I'd imagine this would happen anyway.

I guess what I'm saying is that processing the digital audio should at the base level give the same result on AppleTv or an AV amp, just additional post processing on the amp could tweak it.

I may learn something here!

If you want to send feedback directly to the development team use:

http://www.apple.com/feedback/appletv.html

I don't believe that the Apple TV would have the same capability to decode bit-stream audio as a high-level HD audio receiver or even output the same quality DD 5.1 sound, do you? In fact, many uses on various Apple TV forums have complained about poor multi-channel sound from their Apple TV 4's when compared to their receivers output for the same source. The sad thing is that Apple TV 3 had pass-through audio and some users have compared sound quality between the 3 and 4 models and noticed a significant difference in quality. The only change that would effect sound would be the implementation of Siri.

I have used the link to report the problem, but to no avail.

I wondered about this when I first got the ATV 4. Someone recommended this http://developer.dolby.com/News/Dolby_Audio_Support_on_Apple_TV.aspx link for an explanation. It's still complicated, but that's the way it is.

Yes, that pretty much explains it. My A/V receiver always shows that it is receiving PCM from Apple TV. The question seems to be whether the Apple TV is producing the highest quality decoded PCM multi-channel sound..

Everyone who feels this is an issue to update request your feature via:

http://www.apple.com/feedback/appletv.html

sailermon wrote:

I don't believe that the Apple TV would have the same capability to decode bit-stream audio as a high-level HD audio receiver or even output the same quality DD 5.1 sound, do you?

Decompressing a 5.1 soundtrack to multichannel PCM should be a predictable result - the audio is compressed and a decompression algorithm (or chip) is probably licensed to do so. What could be happening if people are noticing degradation is that AppleTV decodes the 5.1 then outputs in a different (poorer) quality rather than simply the result of the conversion.

As I mentioned I've not had my AppleTV 4 connected to my AV system which is temporarily disconnected so haven't been able to test what gets sent to it.

I hope these reports are incorrect but if several have noticed, perhaps not.

Early on there were comments of inferior music audio for ATV 4 vs ATV 3/4 - I tested myself but couldn't tell the difference.

It really does make little sense to me for AppleTV to decode multichannel audio for movies however - a task an AV amp is designed for.

As for PCM output for stereo audio/dialogue this did make sense as if the audio was in AAC many amps previously would not be able to decode it but generally handled PCM.

As for the feedback link, Apple will not comment or send a reply, but they might take the concerns onboard, only time will tell.

Diana.McCall wrote:

I wondered about this when I first got the ATV 4. Someone recommended this http://developer.dolby.com/News/Dolby_Audio_Support_on_Apple_TV.aspx link for an explanation. It's still complicated, but that's the way it is.

Fantastic link Diana. All makes sense now and is pretty silly.

AFAIK the iTunes Store does not offer movies with 7.1 audio yet. The article also suggests if you choose 7.1 you may not actually get the full 7.1 quality depending on how the device outputs it!

I'd probably stick with the Dolby Surround option but it seems stupid the track is decoded and then re-encoded with 'system sounds' when you do this.

Sadly Apple has never seen this device as a potentially audiophile product hence it has always been limited to 44.1 (ATV1) 48 kHz (ATV2-4) in 16 bit resolution music output when Home Sharing from iTunes, even if you say had higher quality 24/96 audio tracks you'd bought from an online music store other than Apple.

I connect my Apple TV 4 via HDMI to my pioneer receiver/home theater, and the audio quality is horrendous, I mean its bad, really, really bad. The volume is so darn low...I have to crank it up so far to get the volume just a little louder. Watching a blu-ray movie is a complete different experience, like a breath of fresh air, amazing audio quality. I have invested A LOT of money in iTunes HD movies, and I expect better audio quality. PLEASE, PLEASE, PLEASE DO SOMETHING ABOUT THIS!!

EDit... Old thread,