Concern:
I have a concern/question that I can't seem to find an answer to out there on the information superhighway. I've been experimenting with and doing some research over analog vs. digital audio connections from cheap Blu-ray/CD/optical media players.
The consensus seems to be that the digital connection (whether it's hdmi, optical or coax) is almost always the better way to go. I'm not arguing with this generalization one bit, as my own personal findings have pretty much fallen in line with that conclusion as well.
The theory here (I think, correct me if I'm wrong) is that the PCM data is read from the CD and is dropped directly onto the digital bus (hdmi in my case) and then decoded by the AVR. In all of my research the assumption that seems to be ubiquitous is that the DAC within the CD/Blu-ray/optical player is being bypassed if you are using a digital link. Can we be so sure of this assumption? Could it be the case that the DAC is still taking place and that the resulting analog waveform is being re-ADC'd in order to be passed along the digital link?
It might not make technical sense, but from a systems engineering, cost, profit margin perspective it wouldn't surprise me to learn that it may have been cheaper and faster to get something to market (especially in the early days of hdmi and digital links from optical players), by tacking on an ADC to provide a way of getting those digital links on their products rather than going back to the drawing board and sort-of re-engineering something that is or was a tried and true staple in most of these players.
I suppose the only way to really verify something like this would be to capture/sniff some data off of an hdmi bus, or gain a glimpse of the data at it's destination (AVR receiver) and compare it to the CD being played.
Anyone have any thoughts on this? Anyone more familiar with CD and optical player designs, especially early or cheap models? I'm guessing the higher end models (early or current) probably did their due diligence and did bypass DACing/ADCing altogether when a digital link was used. At least one would hope.
Thanks!
I think you’re making a mistake to equate coax and TOSLINK with HDMI.
My understanding is that there are limitations associated with DACs that are separate from the disc player if you use a coax or TOSLINK interface – compared with:
- An HDMI interface (e.g., universal player (e.g., Sony UBP-X800M2) connected via HDMI to a modern AVR, or an HDMI DAC), or
- Using DACs internal to the player (e.g., universal player (e.g., Oppo UDP-205 or Sony UBP-X1100ES) connected via analog audio RCA connections to a traditional hi-fi amp).
My understanding is that there are issues regarding outboard DACs with some hi-res formats. I’m not an expert – following is my understanding of some of the issues - hopefully others can share their experience.
Most SACD discs are “hybrid SACD”, meaning that they contain 2 layers: a Redbook CD layer, and an SACD layer. (A very few older SACDs have only an SACD layer.)
The SACD layer has copy protection features. As a result, you cannot play the SACD layer on a PC, or copy the SACD layer (without a “hacking” procedure). (You can play the CD layer of a hybrid SACD on a PC, and you can copy the CD layer.)
Almost all disc players have copy protection features that affect playing SACDs via outboard DACs. Moreover, there are sometimes bandwidth limitations associated with a disc player connecting an outboard DAC. For example, following is an excerpt from the User Manual of my Oppo UDP-205 universal player:
“Due to bandwidth limitations, high resolution audio formats such as Dolby Digital Plus, Dolby TrueHD, DTS-HD High Resolution and DTS-HD Master Audio cannot be sent through the coaxial or optical digital audio output. A reduced resolution version of the same audio track will be output instead. To listen to high resolution audio formats in their best quality, please use the HDMI connection if you have a receiver that handles HDMI audio (see page 12) or use the multi-channel analog outputs if you do not (see page 15).
Due to copyright restrictions, SACD audio cannot be sent through the coaxial or optical digital audio output. To listen to SACDs, please use the HDMI or analog audio connections.
Due to copyright restrictions and bandwidth limitations, full resolution audio from DVD-Audio discs cannot be sent through the coaxial or optical digital audio output. To listen to DVDAudio in full resolution, please use the HDMI or analog audio connections.”
The important takeaway is the difference in the capabilities of analog and HDMI interfaces, vs. TOSLINK and coax.
My understanding (bearing in mind that I’m not an expert) is that if you want a universal disc player, and an outboard stand-alone DAC, and you want to play SACD and Blu-ray, you’ll need a DAC with an HDMI interface. (McIntosh has a proprietary solution for their products that enables playing SACDs.) Examples of HDMI DACs that I’m aware of include the Essence Evolve II-4K, which is a HDMI v2.0a Multi-Channel Audio DAC. And, the Bryston BDA-3 External DAC, which includes an HDMI input – but only supports stereo. (I have no experience with these DACs, and I’m not certain of the formats they support. And I have no experience with their sound quality. There may be other choices.)
A much simpler solution is to get a universal player with built-in high-quality DACs, such as the Oppo UDP-205, BDP-105, BDP-95. I own all of these products and IME they work great with my vintage tube amplifiers. (Unfortunately, Oppo no longer manufactures equipment.)
For a universal player that provides only 2 channel analog audio output (i.e., stereo), then consider the Sony UBP-X1100ES. If you want to spend less, I suggest that you consider the earlier model Sony UBP-X1000ES which is often available as a "manufacturer refurbished" unit on eBay for $280. I have no experience with the Sony players. You can find reviews on AK for the UBP-X1000ES.
Or, connect an “HDMI only” universal disc player (e.g., Sony UBP-X800M2) to a modern AVR via HDMI.
Why is this important? It depends on the genre of music you listen to.
There are many digital formats newer than Redbook CD. Whether these newer formats are relevant to you depends on the music you listen to. (If you only listen to decades-old recordings, you are limited to decades-old technology.)
Modern high-resolution (“hi-res”) formats can deliver 3 benefits for the music I love (classical music):
- Potentially superior audio quality by virtue of 24bit/192kHz or 24bit/96kHz PCM, or DSD, vs. CD’s 16bit/44.1kHz. (Provenance of a recording is critical – i.e., the best audio quality requires modern recordings that were recorded and mastered in hi-res – NOT ripped CDs.)
- Surround-sound (e.g., 5.1, or 7.1).
- High-definition video, which is essential for visual art forms such as opera and ballet, and IMO very enjoyable for classical orchestral music. Moreover, hi-def video can be very useful by displaying an opera’s libretto (in one of several languages) on the HDTV screen.
Which of the following formats are relevant to the genres of music you like?
- CD
- Downloaded hi-res PCM. (E.g., 24bit/192kHz or 24bit/96kHz FLAC from HDTracks.com, or prestomusic.com/classical/formats/download, etc.)
- Downloaded hi-res DSD. (E.g., nativedsd.com, or acousticsounds.com/superhirez, etc.)
- DVD. (E.g., concert videos. One source: https://concertsondvd.com/collections/blueray-concerts. Countless examples on amazon.)
- DVD-Audio. (I.e., older better-than-CD-quality audio recordings.)
- SACD. (Newer hi-res recordings. Countless SACDs are available on amazon.com.)
- Pure Audio Blu-ray. (I.e., newer hi-res audio-only disc –no video. Available on amazon.)
- Blu-ray. (E.g., concert videos. Amazon.)
- Ultra HD Blu-ray. (E.g., state-of-the-art concert videos. Amazon.)
For the classical music lover, all of the above formats are relevant. (My favorite format is Blu-ray featuring DTS-HD MA 5.1. A few Ultra HD Blu-ray classical titles are starting to become available.)
If the classical music lover wants to use a traditional hi-fi amp vs. an AVR, then a universal disc player with analog audio outputs is the solution. (My Oppo UDP-205 (and BDP-105, BDP-95) works great with my late 1950s and early 1960s tube amps, enabling me to play my favorite format for music: Blu-ray classical concert audio/video recordings. For me, the experience of watching and listening to a concert on Blu-ray is much more enjoyable than listening to a CD. My second favorite formats are SACD and Pure Audio Blu-ray featuring surround-sound.)
Therefore, I disagree with your generalization that “The consensus seems to be that the digital connection (whether it's hdmi, optical or coax) is almost always the better way to go.”
I hope this helps.
