Sure, but I2S itself is a standard, there is just no firm specifications on how to transport it. In this specific case, It's a DAC, so it's the receiving end. It's the driving end, and cable manufacturers that worries about that. When there is such standards, this DAC will support it because all it does is just connecting the necessary signals, they don't have to worry about this.Coming from doing pro audio/studio work, installed audio/video for churches and light electrical, I can tell you standards for audio/video/electrical are very important, I just can't imagine installing a connector without a standard, very esoteric.
Check this, with the amplifier A20a and A20h (headphone amplifier).
No. Two companies copying off each other is not a standard. A standard is a defined specification in a written document which a company can agree to adopt and has performance characteristics against which it can be judged.Isn't that what a standard effectively is?
Why does that matter? Works well when you are prototyping and breadboarding. And many evaluation modules or OEM streaming or DSP modules already give access to the I2S interface trough a Pinout. What's wrong with HDMI cable transfer?
I hear you, but really, I'm too lazy to calculate this, but a bit too much fuss is given to this, we are talking data in the kHz range, not in Mhz, it's in the grand sheme of things, low frequncies
[EDIT] Looks like I was color blind about F2 and F7, so I would just point it out on the graph to avoid confusion.
If you want to see the most detailed and precisely named plots (apart from the ones from the datasheet), visit @WolfX-700 's website:
便携设备 曾几何时，我误入一个论坛，看到了这么一篇评测：Review and Measurements of WesionTEK Khadas Tone Board DAC。在一定程度上可以说这个评测把我当时的价值观击的粉碎。就那么一个小小的板子，就那么一点小小的元器件www.l7audiolab.com台式设备 两个月前，我更新了站里的DAC SINAD Chart，在天梯图的前面出现了几个莫名其妙的测量结果。这是什么妖魔鬼怪……乃至于都被搬运到ASR……好吧，无论如何NDA已经过期了…… 今天就让我揭晓…… Topping D90SE （工程机）的测量结果吧……www.l7audiolab.com
As a rule of thumb, ESS linear phase fast filter has the best imaging artifact suppression (120dB, as specified on the datasheet) so it is often the best one appears on the 90kHz BW THD+N plots, but the price is to slightly violates Nyquist.
The blue, dotted-line one is from the Khadas Tone Board which always show up as a template, uses the apodizing filter. Also, the filter numbers (F1-F7) can potentially be shuffled in different products, so ideally, products display and manual should use filter name instead of number.
The brickwall and apodizing filters, at the expense of not violating Nyquist, have poorer imaging artifact suppression, and they have poorer passsband ripples as well, clearly shown on the plots below:
Nice @dsnyder0cnn. Suggest changing the Topping D90SE to Filter 5 "Fast-Roll Linear" (best IMO) to remove all that rippling in the frequency response from the apodizing filter (Filter 1). Thanks for the tip. I plan to measure the amplitude and time-domain behavior of all seven filters…perhaps...www.audiosciencereview.com
OK, yes I guess I needed an other coffee and was completely off with the frequency. Lot of things in what you say make sense, but not enough to say "cant work". Cables can transport much higher speed, and well, as I said, Developpers do this all the time, connecting 2 boards together with I2S. As for Jitter, sorry I didn't get your point. Why exactly it's intrinsyncly worst? You don't have to define the incoming I2S clock as the master clock as for autodetect nothing that can't be done. I agree this is Frankensteinish as of now but I don't see any of this as a fatality.No. Two companies copying off each other is not a standard. A standard is a defined specification in a written document which a company can agree to adopt and has performance characteristics against which it can be judged.
Take a classic audio example: XLR vs RCA.
XLR is a standard. The connector is defined in IEC61076-2-103. All dimensions are given and consistent. Performance is consistent.
RCA is not a standard. It's a plug made by a company that was never properly defined. Some connectors are hollow some are not, some mate on a single point, others on a ring. Amphenol specifies a 15Nm insertion force, Kobi a 4Nm one. I have plugs in the back of my equipment which fall out when bumped. I have others where I think I may break something I have to yank them so hard.
Both of these are related to each other. Answering the second point should tell you the problem with the first. You're *not* in the kHz range, not even close. In fact you're usually in the 192kHz *32bit*2ch = 12.288MHz range. That's the rate for both SD and SCK. MCLK is typically double that at 24.768MHz, and LRCK is fs/256 or fs/128 so 96/192kHz.
All of this a 5V TTL without proper termination means it flat out would not work simply plugging in a HDMI cable, and if it did work you're likely to end up with jitter so bad amir may actually complain about it ;-).
And that's also why it isn't done in any of these DACs. I2S is first converted to LVDS (Low voltage differential signaling - 8 pins) before being connected to a HDMI cable. It's the only way you have any hope of getting the signal more than a few centimeters in the first place.
But ... remember what I said about fs/256 and then I used the word "or"? It's more complicated than that. I2S doesn't define a standard, it just defines ratios. Your MCLK may be 36.864MHz and your LRCLK fs/192, some DACs can autodetect this, some expect to be told. The audio interface bitdepth can't be auto negotiated so your DAC needs to understand in advance if it is getting 16 20 24 or 32bit, though many will work if they receive less than expected they will fail if they receive more.
Just having I2S capability doesn't guarantee two chips can talk to each other even if they receive the data correctly, and even if the HDMI cable is connected the same way at both ends (again, no standard).
This is why it's appropriate to shout "It's alive! It's alive!" when connecting two devices using this I2S over HDMI Frankenscheme.
It all depends on the filter length of a specific chip. The article below is specifically written to answer these kinds of questions.Okay, so let me ask you something just quickly since I heard John, amir, and someone else claim something of the sort that a proper brickwall can never have the flat and smooth suppression of artifacts as seen in the filters you see with minimum/linear ones you call them.
Is this true? All brickwalls must by definition have this jagged performance unequivocally ? And this is a fact that is observed as a brickwall filter tries to respect Nyquist, and the cost is paid in this way?
SIM cars and Thunderbird, hmm, let me guess - you been spending a lot of time in your garage, or perhaps behind a Fanatec wheel!If the port works, the port works. If there is a formal standard or just a casual agreement, what does it matter? I haven't seen posts saying, "I2S doesn't work!" I have been seeing posts complaining about some violated aesthetic engineers hold dear.
I've deal with plenty of well-documented standards that have issues. USB and Thunderbird are messes. Wifi? Oof. SIM cars? Double oof!
If you are going to pirate a connector then the locking display port would have been a much better choice.SIM cars and Thunderbird, hmm, let me guess - you been spending a lot of time in your garage, or perhaps behind a Fanatec wheel!
It is a disaster. They couldn't even get the simple signaling standardized for the connector in such a simple application. Here is *part* of the documentation in A20d on I2S signalling:I agree this is Frankensteinish as of now but I don't see any of this as a fatality.
Ha OK, I didn't know there was 4 versions already, well at least they offer them all? As I said, in my view it is not very useful now, if at all and I know full well there is no benefits if we mean in term of performance, but there is no drawback neither. Standardisation ACTUALLY adds cost, you know that a licence to have a USB port is about 4K a year? It is what it is and you are right nobody needs this, until they do, it's a new interface, new possibilities, it may never be found useful but in the future if it gets used in more upstream product, well, they'll have it. You know you can't send DSD over SPDIF right? well that's one use case because, for a non-computer device, a "non-CPU based" streamer for exemple, dvelopping a audio class 2 usb OUT is much more complicated and costly, than that, because that you already use this signal internally. Sure nobody really need DSD, but it's out there. If you are a DAC manufacturer today, and your DAC don't do DSD, many wouldn't buy it just because this is what it is, FOMO. It adds cost, but they WANT to add cost, DACs are cheap to make, all companies competes with offering exactly the same thing. They have to be creative in order to differentiate. Nobody needs a 1000$ DAC, still some will buy it for that tiny little performance bump likely inaudible. If you ask me I would much rather have DSP than a connector like that, but why not, it's still only a 400$ Box, in ratio to a full hi end system, it's nothing, I think that's the point.It is a disaster. They couldn't even get the simple signaling standardized for the connector in such a simple application. Here is *part* of the documentation in A20d on I2S signalling:
View attachment 157960
Get it wrong and you get all kinds of weird results.
On top of this, there is no benefit to this interface. It is just adding cost and confusion.
They boil down to Topping/SMSL/Sabaj etc not having 'a sound'