I would like to connect my Oppo105 BluRay player to the Cascade when I watch bluray concerts or operas. Right now, the player is connected via its analog XLR outputs directly to my stereo preamplifier bypqssing the Cascade which is frustrating.
I tried a connexion from the Oppo Dig Output via a very good coaxial cable to the Cascade SPDIF input card but the sound wasn’t good enough in comparison to the XLR analog outputs, and I know for sure that it is not the Cascade or its SPDIF input card that are to blame because my Tuner T1000 is connected via its Dig output through the same coax cable to the Cascade SPDIF and the sound quality of the live radio is excellent. So my guess is that the chipset behind the Oppo Dig Out that outputs the SPDIF signal may be of poor quality. Understandable that Oppo had probably not invested too much on this output.
So, could MSB contemplate to design an audio HDMI input card ? This would allow to connect either a TV or the second (audio) HDMI stereo output of the Bluray player, my use case.
Most recent all-in-one players have an ARC/eARC HDMI input now, the likes of Eversolo DMP-A6 which drives another smaller system of mine, or Cambridge or Auralic, or a bunch of other brands…. So why not MSB.
And it does not matter if the DD is bypassed. The quality of the Cascade DAC would be so much better than the Oppo105’s internal DAC. Watching/listening to operas via the Cascade would be such a thrill !
I know what you are going to tell me : no one buys anymore a bluray or UHD/4k player as lots of films are are available on Line. Okay but how many of us, owners of an MSD DAC, own already a bluray or UHD/4k player ? Quite some I would imagine.
Voilà a good Christmas present you could propose to your patrons if technically feasible you could refuse the same form factor as the I2S input card but with the appropriate electronic inside.
The Inter-IC Sound (I2S) protocol is a serial communication standard designed specifically for transmitting digital audio data between integrated circuits.
The I2S interface is totallly different from the standardised HDMI protocol used in video/audio, even if you can use a standard HDMI cable on the I2S MSB input card.
I2S uses an HDMI « connector », that is the only commonality. What travels on the 19 pins is different between the HDMI standard and the I2S protocol. So in my understanding the I2S is not reprogrammable. My 2 cents
@Abascal I understand the difference between I2S and HDMI, in a general way. My speculation involves the programming of whatever chip is being used to decode the I2S to strip out the audio portion of the HDMI signal.
Pure speculation, and dreaming. I know some (many?) of us are using our DACs for listening to TV+BlueRay video.
HDMI =about 4-8Gbps, I2S =about 3-100Mbps. This means the slowest HDMI is 40 times faster than the fastest I2S data rate and requires completely different hardware to decode. It also means that for an example of 44.1-48Khz audio sample rate over HDMI has only about 0.1% of the data representing audio. This illustrates how an HDMI interface has very little priority for high quality audio. It is really designed to carry video with the audio being a complete afterthought shoehorned into the system. I2S and HDMI are really just sharing wires and a connector, there is absolutely no compatibility between them.
In order to strip audio from HDMI the entire signal, video, audio and control, needs to be decoded, uncompressed (HDMI is compressed data), decrypted (HDMI is encrypted), then the audio data may be stripped. However even then the data is not enough because it is timed by the video data, which is not related to the audio data rate, so the audio clocks need to be regenerated by averaging and slewing along with the video data rate, this tuns out to be a very difficult process to do well unless you just store the data in a large buffer and play it back, however this generates a large delay with lip sync issues.
HDMI =about 4-8Gbps, I2S =about 3-100Mbps. This means the slowest HDMI is 40 times faster than the fastest I2S data rate and requires completely different hardware to decode. It also means that for an example of 44.1-48Khz audio sample rate over HDMI has only about 0.1% of the data representing audio. This illustrates how an HDMI interface has very little priority for high quality audio. It is really designed to carry video with the audio being a complete afterthought shoehorned into the system. I2S and HDMI are really just sharing wires and a connector, there is absolutely no compatibility between them.
In order to strip audio from HDMI the entire signal, video, audio and control, needs to be decoded, uncompressed (HDMI is compressed data), decrypted (HDMI is encrypted), then the audio data may be stripped. However even then the data is not enough because it is timed by the video data, which is not related to the audio data rate, so the audio clocks need to be regenerated by averaging and slewing along with the video data rate, this tuns out to be a very difficult process to do well unless you just store the data in a large buffer and play it back, however this generates a large delay with lip sync issues.
For our Oppo based transports that we previously produced I circumvented these issues by reversing the timing priority. I slaved the entire player to the audio clock rate by programming a digitally controlled PLL (phase locked loop) to control the frequency of the video oscillator to keep the video in sync with the audio playback clock, the opposite of all other DVD players.
To properly play HDMI audio, you have to have all the licenses (there are many), including DTS/Dolby/etc…. and this just isn’t a possibility anymore. You used to be able to sub-license this thing, but that was closed many years ago, making a proper HDMI audio input impossible. You can do a partial input but it won’t work with all sources and therefore we won’t even consider it.
For the Oppo digital output, it won’t do DSD, but if you get the settings right, it might sound ok. You need to set the output to PCM, front speakers to “large” or it applies an EQ, as well as 1 or 2 other settings I can’t remember at the moment.
Given that many „affordable“ streaming amplifiers (i.e. in the 500-1,000 USD realm) today have an HDMI ARC/eARC input at least for 2 channel audio, the whole licensing issue cannot be prohibitively expensive to making a digital input module that will sell for north of USD 1,000 like all the other input modules. Surveys show that many users, including „audiophiles“, have a TV on the front wall between their speakers and would benefit from an HDMI eARC connection which sonically and regarding seamless integration (volume control) is the best solution to connect a TV to the main stereo system. Given this widely existing potential use case, isn‘t it somewhat snobbish to rule out the possibility completely and for good?
@itoakio , fair point, but the future is an open door and we are not ruling out the possibility completely. At this time however, we do not have the demand to make it viable. The annual licensing is a fixed fee, not a per unit price. If we sold many thousands of inexpensive products, the price would be distributed across those devices (even different product lines) and become quite affordable. With an example of a annual license fee exceeding 100K USD, we would need a surcharge of 10K for each module of a 100 piece production. Not viable from our perspective.
But, that may change in the future. For now, we are a small and very focused on audiophile quality inputs first and foremost. We have Analog pass through for multi-channel setups and the toslink SPDIF out of most TV’s works quite well.
For sure. In the past, there was a loophole for small companies. A larger firm would get a license and then manufacture and license PCB’s for many small companies. Spreading the cost across many productions of different products. Sadly, this loophole was closed. It would have been a perfect solution for us! Alas.
