James, have you taken the trouble to check out The McGurk effect, The ambulance color test, and read this:
https://www.harman.com/sites/default/files/white-paper/12/11/2015 - 05:54/files/AudioScience.pdf
forward to page 10, BLIND vs. SIGHTED TESTS – SEEING IS BELIEVING?
The reason I ask is that these things can throw a very unexpected light on how we form opinions and convictions, how the process of coming to a conclusion is influenced by many things we often neglect.
Jan
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Jacob, seriously? We're talking data transport. Would you say the same about your operating systems updates? Are yours somehow different than mine even if their data is matched?
Unfortunately not.... 😎
Instead of that we´re talking about a music reproduction chain that produces analog output signals in realtime (at least that´s my understanding from James description), 😉
And James thinks that the sound will be altered if the cd transport is exchanged.
Could it be just an imagination? Of course it could be.
Must it be just an imagination? No, of course not.
Should it make a difference if the transport is exchanged? No, of course not.
(It´s a bit similar to the intersample overs situation. Should intersample overs be possible? No, of course not.)
Does the fact, that it shouldn´t mean that it doesn´t? No, of .........
That is an inadequate comparison and will therefore not help.
Okay, here's a simple request to hopefully guide the discussion (I'm openly being Socratic here): can anyone wondering about the audible importance of a CD transport please explain how the data moves from the CD read mechanism to the receiver on the DAC?
We need to start somewhere, as it seems this is being missed in a big fashion.
We need to start somewhere, as it seems this is being missed in a big fashion.
Not all circuits are perfect. As was posted before, some receiver chips or circuits don't deal well with bad input signals. They don't stop working on all of these signals, on some they work and sound awful. It isn't subtle. Nice thing about digital is that it is not hard to get above the threshold were everything works just fine. And of course there is a threshold below which it stops working at all.
Probably did somewhere here on the forum. Finding it won't be easy.
I didn't get crazy with the tests, as in each case I found bit perfect to be the default.
Of course I came across CDs that would not play or rip without faults, but those were rare or very damaged. I don't blame the transport for that.
I didn't get crazy with the tests, as in each case I found bit perfect to be the default.
Of course I came across CDs that would not play or rip without faults, but those were rare or very damaged. I don't blame the transport for that.
Okay, same question I asked others--please explain how data moves from your CD to the receiver on the DAC.
Because much of what we take for granted as far as digital signal transmission (EVERYWHERE) would fall apart given your assertions. But why let ignorance get in the way of a philosophy?
You have an active imagination. I bet you cannot see the irony in disproving John A's assertion because it is not meeting the burden of scientific proof, and then not providing verifiable evidence, even if by citation.
I am actually skeptical about CD transports. I think it is all in John A's head and not audible. I am still struggling with the argument that CD transports are bit perfect because of the IT industry. I can think of ways that work around being bit perfect from my own background. I also think if the first CD transports were bit perfect somebody would have started working on a way around that that would save cost in IT applications. Again I'm focusing on IT as the argument not CD audio.
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I'm certainly not following the second half of your argument; I think you're saying one thing but I'm probably misreading.
I appreciate your call to irony, but Pano has done a number of documented tests on this site, so there's a certain bit of capital that he can bank on, at least for me (clearly not for you). I haven't run that test either. I have messed up bit streams and listened to the horrid sounds that evolve when you screw up the data. Not recommended. 🙂
As to propagated bit errors--they're pretty rare. Of course you get errors in before the parity check (and/or a need for a resending of the data, which kills throughput), but I'm talking about end-to-end, with all protocols in place. If we had a lot of bit errors, we'd be in major trouble.
I appreciate your call to irony, but Pano has done a number of documented tests on this site, so there's a certain bit of capital that he can bank on, at least for me (clearly not for you). I haven't run that test either. I have messed up bit streams and listened to the horrid sounds that evolve when you screw up the data. Not recommended. 🙂
As to propagated bit errors--they're pretty rare. Of course you get errors in before the parity check (and/or a need for a resending of the data, which kills throughput), but I'm talking about end-to-end, with all protocols in place. If we had a lot of bit errors, we'd be in major trouble.
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There are other factors other than jitter that make transport sound different (even assuming exact same bit transfer). As mentioned before input circuitry on the DAC itself is one factor, even with bit perfect transfer will have different noise injected to/from it and cable too.
No two jitter sounds the same.
No two PSU sounds the same.
why not sound the same ? lets not go there lol
I'm sorry but if it often takes Exact Audio Copy sometimes a few minutes to process the same sector that's hard to read depending on your drive, there's no way in hell transports are perfect. Not a ******* chance. Different laser designs will vary disc to disc due to angles, just like when ripping CD's. Can't believe I forgot some of that.... Tis true.
Furthermore a transport needs to be not too noisy and ideally not generate reflections on the SPIDF output (a 6ft cable typically eliminates this IIR, so it's worth a try/start with it). Noisy transports can make DAC's lose sync... I have to imagine even when that doesn't occur, the noise isn't improving sound. This seems somewhat clear given the fickle nature of SPIDF recievers and the high preferance towards I2S or AES.
How much does it all matter? I'm not certain, really. I don't know for sure if you can hear it, because I haven't swapped enough transports I was sure we're working correctly.
Furthermore a transport needs to be not too noisy and ideally not generate reflections on the SPIDF output (a 6ft cable typically eliminates this IIR, so it's worth a try/start with it). Noisy transports can make DAC's lose sync... I have to imagine even when that doesn't occur, the noise isn't improving sound. This seems somewhat clear given the fickle nature of SPIDF recievers and the high preferance towards I2S or AES.
How much does it all matter? I'm not certain, really. I don't know for sure if you can hear it, because I haven't swapped enough transports I was sure we're working correctly.
By IT I presume you mean networking, LANs etc. if so the relevance to CD transports is pretty much nil, we are talking about getting the bit-stream a metre or so to the DAC not through over 10s to 100s of metres of networking cables...
Some data to back this up...
Jitter these days is pretty much a zero problem, do some research and reading of some of the qualified posts on this site.
Noise, if the DACs are that badly designed that every PSU sounds different then something is wrong. Again some measurements of this noise and the effects it has would back this up...
There have been numerous discussions on the SPDIF interface that go against this view, including many waveforms shown and discussed. The interface done properly is not that bad.
Curious as to how a 6 foot cable helps signal integrity, digital interfaces should be as short as possible...
No offense
But if you havent tried it, please dont let your view of "measurement shows nothing" dissuade other diyers to try and get improvement from PSU change. Numbers getting harder to measure as it goes low yet audio circuit is still nowhere 100% transparent.
For people who want to see the number first then believe it, well that's fine until it can be properly documented one day (if ever).
any audio circuit benefit from better PSU, even SPDIF receiver chip PSU can be heard. DAC chip PSU even more so, please kindly try if you are skeptical (this is diy, should be one of top list ) . Most (maybe all) DAC power supply rejection ratio is just acceptable
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Of course fully sighted testing of a mod you have done is proven to the best way to judge audible effects.
I have no problem with SPDIF personally, but it does seems unnecessary generally as a format that exists to exist between two things using the same different format. It seems to be a minor point of contention for choices when you look at many DAC's being talked about.
The problems with reflections in SPDIF cables is beyond my scope, but this was a discussed thing probably 10 years ago, maybe more?
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