[skhan007]

I think I may know the answer, but I really do value the opinions on this Head-Fi subform, as I always learn some great information.

My scenario: I've got several Blu Ray and DVD-A discs from a few bands that I really like, many of which have music in 24/96 resolution. However, when I play them on my Blu Ray player (Panasonic DMP-BDT360), the screen says LPCM 24/96, however my RME ADI2 DAC connected via optical cable, reads 16/48 and sometimes 24/48. No matter how I set the player's settings, this is the result.

I'd like to know the science behind transfer of digital audio from the source to the DAC and what is happening in this signal chain to account for the downsampling of the music. Better yet, how do I correct it? I've read I could try and HDMI extractor and see if I can get the audio signal from the HDMI output and transfer it to the DAC via optical cable. Second, I might need a new/better Blu Ray player, but have no clue what brand/model that would be.

Lastly, if I have music on the BluRay disc in 24/96 resolution, and it's downsampled to 16/48 on my DAC, do my ears notice a difference? I believe 16/44.1 is as good as the human ear can hear. If I were a dolphin, sounds above 44.1 kHz are detectable, but not music, correct? I read the Nyquist article a while back.

Any recommendations regarding my Blu Ray player, replacing it, routing through an HDMI extractor, etc. are appreciated. Thoughts on the resolution and just sticking with whatever the DAC reads, are also welcome.

 

[PurpleAngel]

Your Panasonic DMP-BDT360 has an audio setting, PCM Down Conversion, when it's on, it converts audio down to 48k,
so if you set it to off, audio higher then 48k should flow straight out the S/PDIF (optical or coaxial).
https://www.manualslib.com/manual/751068/Panasonic-Dmp-Bdt465.html?page=27#manual

 

[skhan007]

Your Panasonic DMP-BDT360 has an audio setting, PCM Down Conversion, when it's on, it converts audio down to 48k,
so if you set it to off, audio higher then 48k should flow straight out the S/PDIF (optical or coaxial).
https://www.manualslib.com/manual/751068/Panasonic-Dmp-Bdt465.html?page=27#manual

Thanks- yes, it’s set to off and yet my results don’t change. Very strange, right? I can’t figure it out. I’ve read the manual carefully.

I read that sometimes, there’s copy protection on the Blu-ray discs and only the HDMI out carries the high def audio (not coax/optical). If that’s true, then I need to extract the audio from the HDMI out and send it to my DAC. I could be wrong on this, however.

 

[sander99]

Better yet, how do I correct it?

Note that it is not always possible to avoid downconversion, as stated in below quote from the manual mentioned above:

Signals are converted to 48 kHz despite the settings in the following cases:
– when the signals have a sampling frequency of 192 kHz
– when the disc has copy protection
– when "BD-Video Secondary Audio" is set to "On"

I think in the case of a disc with copy protection it is the same for all players (because of regulations), or most for sure.

The good news: if the downsampling is done correct (which I assume) then it should indeed not make an audible difference.

 

[sander99]

the HDMI out carries the high def audio (not coax/optical).

Ah, that could be true. But it really should not make an audible difference so I wouldn't start jumping through hoops to "correct" it.

 

[skhan007]

Ah, that could be true. But it really should not make an audible difference so I wouldn't start jumping through hoops to "correct" it.

Note that it is not always possible to avoid downconversion, as stated in below quote from the manual mentioned above:

I think in the case of a disc with copy protection it is the same for all players (because of regulations), or most for sure.

The good news: if the downsampling is done correct (which I assume) then it should indeed not make an audible difference.

Ok, that’s really good to know. I appreciate it. My thought was that it may not be an audible difference. I definitely tend to jump through hoops if I suspect something is not optimal. I think I’ll test drive the HDMI extractor device, but if that doesn’t produce any benefit, I suppose I’ll just accept the cards that are dealt.

 

[Davesrose]

Thanks- yes, it’s set to off and yet my results don’t change. Very strange, right? I can’t figure it out. I’ve read the manual carefully.

I read that sometimes, there’s copy protection on the Blu-ray discs and only the HDMI out carries the high def audio (not coax/optical). If that’s true, then I need to extract the audio from the HDMI out and send it to my DAC. I could be wrong on this, however.

Are these discs surround sound? Theoretically, the only way to get 96KHZ digital audio through optical is stereo (and on certain codecs). It's not just copy protection, but bandwidth for optical: which at best is 3Mpbs. Lossless surround (even 24bit 44.8) can average over 4Mpbs. For 5.1 surround, it's usually compressed Dolby Digital that gets sent through optical. I have many blu-ray concerts that are PCM stereo and DTS-MA 96KHZ surround: and I run them through HDMI to my receiver (DTS-MA 96KHZ is not possible with optical because of standards). It doesn't really matter much if you are getting the desired stereo or surround sound you want (so if it sounds good at this stage, why consider a HDMI extractor?). With concerts on my surround speakers...I consider the native 96KHZ I get with HDMI might have slight advantage with levels and subwoofer...but certainly they are minute differences and not equivalent to what a HDMI extractor would do.

 

[sander99]

I assumed he was talking about stereo because his RME ADI2 is a stereo DAC (and headphone amp).

 

[skhan007]

Are these discs surround sound? Theoretically, the only way to get 96KHZ digital audio through optical is stereo (and on certain codecs). It's not just copy protection, but bandwidth for optical: which at best is 3Mpbs. Lossless surround (even 24bit 44.8) can average over 4Mpbs. For 5.1 surround, it's usually compressed Dolby Digital that gets sent through optical. I have many blu-ray concerts that are PCM stereo and DTS-MA 96KHZ surround: and I run them through HDMI to my receiver (DTS-MA 96KHZ is not possible with optical because of standards). It doesn't really matter much if you are getting the desired stereo or surround sound you want (so if it sounds good at this stage, why consider a HDMI extractor?). With concerts on my surround speakers...I consider the native 96KHZ I get with HDMI might have slight advantage with levels and subwoofer...but certainly they are minute differences and not equivalent to what a HDMI extractor would do.

A few discs are just LPCM stereo 24/96 and others have audio menus where you can select 5.1 or LPCM 24/96. For those discs with audio setup, I will choose 24/96, but my DAC will see it as 24/48 or in one case 16/48.

Oddly, I have a couple of DVD-A discs (from King Crimson box sets) that are labeled as 24/96 and it will be properly received by the DAC as 24/96. So, that shows that the player and optical connection to the ADI2 DAC are capable of this resolution transfer and it shows that there's something up with the Blu Ray discs.

The reason I'm troubleshooting this is not because there is degradation in the sound quality (through headphones, the 24/48 sounds good), is because the Blu Rays were purchased for hi-res, were advertised as hi-res, and it's somewhat of an annoyance that they're not playing as intended/advertised. To get close to CD quality (16/48 is roughly that) when you paid for 24/96 is a bummer. Hope that makes sense. Also, good to know that you detect minute differences with native 96kHz. Honestly, if I can't resolve this, I'll just live with it. Life is too short and I've got a lot music to enjoy!

I assumed he was talking about stereo because his RME ADI2 is a stereo DAC (and headphone amp).

Correct!

 

[skhan007]

Quick update: I went to my local Best Buy and bought their HDMI Audio Extractor. Mixed results- For the Blu Ray music that should play in LPCM 24/96, but was playing in 16/48, it was upscaled to 24/48 (but not the 24/96 as intended).

When I put in a DVD-A that was previously playing at 24/96 properly, it was downscaled to 24/48. Really strange stuff happening here. I wish I could understand the science of digital audio to have an explanation as to why all this is going on. I'm going to return the HDMI extractor to Best Buy later today. Bummer.

 

[sander99]

the Blu Rays were purchased for hi-res, were advertised as hi-res, and it's somewhat of an annoyance that they're not playing as intended/advertised

The idea is that the Blu Ray player itself will play high-res using it's internal DAC and analog outputs. It is not advertised that you can play it via digital outputs. Although on the surface it is suggested somewhat by the players specs stating the digital outputs can handle high-res, it is in the "small print" that it is not always allowed because of copy protection.

Edit: oops, I looked at the manual and it doesn't seem to have analog outputs...(?)

Edit2: I guess it should work via HDMI to a surround receiver or other device with HDMI input and analog outputs. HDMI audio extractors maybe are also not allowed to output it via optical or coaxial digital out.

 

[bigshot]

I have an Oppo player and I set it to send out PCM instead of bitstream. I have found the closest you can get to plain vanilla formats, the least chance of glitches or lag. I think you have to use bitstream for Atmos though.

 

[71 dB]

The reason I'm troubleshooting this is not because there is degradation in the sound quality (through headphones, the 24/48 sounds good), is because the Blu Rays were purchased for hi-res, were advertised as hi-res, and it's somewhat of an annoyance that they're not playing as intended/advertised. To get close to CD quality (16/48 is roughly that) when you paid for 24/96 is a bummer.

Hi-rez consumer audio is a scam. CD quality is all we consumers need no matter how golden ears we have. Even lossy formats above 200 kbps often* provide totally transparent audio and after these kind of technical parameters are met, the sound quality comes from how well the music has been produced: Performed, recorded, mixed and mastered. Those things dictate how good it sounds. So, start enjoying your music and forget it is "only" 24/48 or 16/48.

* Some obscure "killer tracks" perhaps making an exception.

 

[skhan007]

I have an Oppo player and I set it to send out PCM instead of bitstream. I have found the closest you can get to plain vanilla formats, the least chance of glitches or lag. I think you have to use bitstream for Atmos though.

There are a couple of Oppo players on my local craigsist. The 83 (pretty cheap) and the 93 (asking price close to $500!). Curious if the cheaper 83 model would do what I'm looking for.

Hi-rez consumer audio is a scam. CD quality is all we consumers need no matter how golden ears we have. Even lossy formats above 200 kbps often* provide totally transparent audio and after these kind of technical parameters are met, the sound quality comes from how well the music has been produced: Performed, recorded, mixed and mastered. Those things dictate how good it sounds. So, start enjoying your music and forget it is "only" 24/48 or 16/48.

* Some obscure "killer tracks" perhaps making an exception.

Yeah, this is the other thing I was considering. Will my ears notice any difference? I'm guessing not.

 

[PurpleAngel]

Might consider converting your music disks into FLAC files and load them on to a DAP.