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Gah. 'Audiophile' USB Cable. - Page 3

post #31 of 191
Quote:
Originally Posted by Skyyyeman View Post

Couldn't find the link

Use Google.
post #32 of 191
Quote:
Originally Posted by cel4145 View Post


Use Google.

Gee, that's really a great idea.  (But I already had it in a Word doc so that's what I used, since I didn't want to go searching around and waste more time.)

post #33 of 191
Quote:
Originally Posted by Skyyyeman View Post

Gee, that's really a great idea.  (But I already had it in a Word doc so that's what I used, since I didn't want to go searching around and waste more time.)

Took me 10 secs to find it. tongue.gif
post #34 of 191
Quote:
Originally Posted by cel4145 View Post


Took me 10 secs to find it. tongue.gif

Excellent job, way to go!!

 

Frankly, I didn't even bother to search since I already had the text (but without the link, after looking for it in my doc for maybe 1/500 of a sec). Time to put this major Google/search/link issue to rest and move on to the lesser issue of USB cables, the article itself, 1s and 0s, etc.  

post #35 of 191
Quote:
Originally Posted by cel4145 View Post


Took me 10 secs to find it. tongue.gif

BTW, I happen to agree with your earlier comments.  I've experienced significant differences between digital cables, including USB cables.

post #36 of 191
Quote:
Originally Posted by Chris J View Post
 

Oh man.

Holy wall of text!

You could have just posted a link!    :wink_face: 

And not much of it had to do with USB cables, and otherwise kinda misses the point (if there was one(?)) :rolleyes:.

post #37 of 191
Quote:
Originally Posted by Skyyyeman View Post Warning: Spoiler! (Click to show)
 

USB cables are digital cables, which have significant differences between them, the same as analog cables.  See the below article entitled "Digital is Analog", featuring several top digital designers and manufacturers.

 

Conversation with Charles Hansen, Gordon Rankin, and Steve Silberman
By Michael Lavorgna  Posted: Jun 24, 2013

During a conversation with AudioQuest's Steve Silberman, Steve brought up the notion that "there's no such thing as digital" which I found thought provoking. I suggested to Steve that we have an email conversation about this very topic and Steve suggested adding Charlie Hansen of Ayre Acoustics and Gordon Rankin of Wavelength Audio into the mix. So that's what we did. The opening question:


It's common for people to envision and represent a digital signal as a series of 1s and 0s. As such, there's really no room for error, at least according to this binary theory. Is a digital signal simply a series of 1s and 0s?


Charlie Hansen: Unfortunately not. The "1"s and "0"s are just abstractions that are easy to think about. But in the real world, something real needs to represent those two abstract states. In modern digital electronics, we have almost universally chosen a voltage above a specific level (that varies from one "family" of electronic parts to another) to represent a "1" and a voltage below a different specific level (that again can vary) to represent a "0".
In the real world, those two voltages are not the same, so there is a "grey" zone between the "black" of the "0" and the "white" of the "1". Also, it takes time for the signal to change levels, and the time required to do so can depend on dozens (or even thousands) of other external factors.


"All of the problems with digital are analog problems."
All of this can be boiled down to a simple phrase. "All of the problems with digital are analog problems."
This is the primary reason that digital audio has taken so many decades to come close to the sound of analog. When digital audio was introduced, none of the top analog designers of the day knew anything about it. So it was all designed by digital engineers. Digital engineers have gone through years of training where these problems were never mentioned. And as time went on engineering schools put less and less emphasis on analog circuit design.
There is an entire generation of designers that lacked even a basic understanding of analog electronics. And without a thorough knowledge of analog electronics, the problems of digital can never be addressed, let alone the problems of analog electronics, which will always be necessary. Currently good analog engineers are in high demand because there aren't many of them left! So a lot of schools are adding analog electronics back into their curricula.
We live in an analog world, and all signals start as analog signals and must be returned to analog for audio playback. Modern video displays are about as close to pure digital as we've gotten so far, and even there the fact that there are still analog problems in digital electronics is what separates the good from the great.


Gordon Rankin: Many people talk about digital data and bit perfect in a singular sense. But in reality things are very different. The testing involved with doing a real bit test is larger than anyone really would want to take on. Just using the obvious methods of the indication of a HDCD marker or recording a signal and taking the analog equivalent and subtracting them to see a difference only covers a really finite amount of what a true bit perfect test is. How about we take a song output over an S/PDIF transmitter to an S/PDIF receiver, record that and compare the two (original file and the data received)? Why stop at one song, but maybe 10, 20 songs, 8 hours worth.
But aside from the data being true, there is so much more. How much energy is wasted delivering the data seems to have an effect on sound. As with increased energy usage the amount of EMI/RFI radiation also increases. This might be a reason why applications sound different. If we look at the "top" command in the Terminal application on OS X we see a programs usage and percent time and all the processes associated with that program. In practice the applications with the least required processing time also sounds the best. This may have an indication of why file types sound different. If you unpack a lossless file on the fly the processing time increases measurably and that tends to decrease the sound quality.


"People talk about USB and Firewire jitter being an issue and it can cause data errors. But really this is not the audio related jitter error that is most important."
Also how do we get the data there is a whole other topic to be taken on. We are basically packing audio data up into finite packets of bytes and then sending them over some serial link, one bit at a time and then rebuilding this data into a format for which the DAC chip will accept. People talk about USB and Firewire jitter being an issue and it can cause data errors. But really this is not the audio related jitter error that is most important. That has to do with the way the DAC receiver formats output data to the DAC chip and the associated audio master clocks and audio serial format (I2S, left justified, right justified, DSD, etc...). Then there is flow control over the network from the computer to the DAC. I don't know if any of you are looking at this... I have and it's not a pretty sight. So just doing this on average is not a good thing and there is an appreciable difference in sonics depending on the way you handle this.
Anyone who feels it's only "1" and "0" is missing a ton more variables that need to be addressed.


CH: The complete system used for CD's was developed before CD-ROMs were used for computers. It was only later when people started to realize that a CD could hold MUCH more data than any other transportable medium of the time (eg, 650 MB for a CD-ROM versus 1.2 MB for a 3-1/2" high-density floppy disk) that they adapted the CD for use with computers.
There are several very clever back-up and redundancy systems built into the audio CD format so that it is fairly rare for there to be an actual error in the bits (eg, a "1" will be misinterpreted as a "0" or the converse). However, the error rate is still too high to be used for computer files, so another layer of error correction is added to a CD-ROM in addition to all of the error correction systems found in a CD.


NB:Copying an audio CD to a CD-ROM will NOT use this extra layer of error correction, so there is no reason to copy all of your audio CD's to CD-ROM's. However if you rip your CD's to your hard drive using a system such as AccurateRip (employed in several ripping programs, such as dBpoweramp, see wiki.hydrogenaudio.org/index.php?title=AccurateRip for additional information), the checksum from your disc rip is compared to hundreds (or even thousands) of other submissions from other users and you can be confident that the audio data on your hard drive is a bit-perfect copy of the original master used for the CD. At this point, the data correction built into your hard drive will take over and protect your audio albums from any possible corruption -- at least until your hard drive fails. This is inevitable -- ALL hard drives will fail sooner or later, so be sure to BACK UP your music files!)
Getting back to the "grey zone" that exists between a "0" and "1" in ANY digital system, it is rare that the errors are so large that there will be actual corruption of the data. It can happen -- most people have seen a digital display connected with a cable that is either poor quality and/or too long for its intended purpose. Often this will show up as green "streaks" in the picture. It can also happen with audio. If the cable connecting the DAC to the computer is either poor quality and/or too long for the system in use, there may be randomly audible "ticks" or "pops" during playback.
"But since digital audio is a streaming system, the timing of the bits is critical. If the bit changes to the correct state but at the wrong time, this is equivalent to changing to the wrong level at the correct time."
However, it is important that ALL audio systems will suffer ill effects from this "grey zone" even if there are no obvious audible problems. This is because the error is not large enough to change the state of any particular bit. But since digital audio is a streaming system, the timingof the bits is critical. If the bit changes to the correct state but at the wrong time, this is equivalent to changing to the wrong level at the correct time. These timing errors are known as "jitter".
[GR: Audio streaming protocols are typically not error correcting. Standard Asynchronous and Adaptive protocols only cover flow control, not error control. The analog behavior at the receiver side of any streaming interface can have a lot of effect on the quality of the received data which will directly reflect the quality of the audio.]
It is rather unfortunate that jitter was the first timing error to be described in the context of digital audio, as it has become by far the most common way to refer to timing errors. But it turns out that far more important than the absolute amount of timing error is the spectral distribution of the error (ie, how much error is there at high frequencies versus low frequencies), and whether that timing error is correlated with the audio data (music signal) or if it is just random variations.
More sophisticated test equipment is required to test for this, and you will see this referred to as "phase noise". The phase noise is measured at a frequency that is offset from the desired carrier frequency. A graph of the phase noise versus the offset frequency provides us with information regarding the spectral distribution of the jitter, and is the best tool to date for measuring timing errors (ie, "jitter") in audio equipment, as it is the most sensitive tool and has the highest correlation with audible differences.


AS: Since there's no such thing as 1s and 0s in digital transmission, what is being sent over our USB/Firewire/Ethernet cables when we play back music files?
CH: An ANALOG signal!


Steve Silberman: I think this is where things get misconstrued. The signals we think of abstractly as “digital” are in fact high-speed analog square waves, susceptible to all of the same damage and distortions as any other analog signal.


AS: So when we talk about digital music playback, we're talking about a continuous system as opposed to a discrete system. In effect, once we hit play, our data is transformed from a discrete state into a continuous state which is, for all intents and purposes, governed by the laws of the analog world. And one of the most critical aspects of this continuous music playback system is time/timing errors/jitter.


GR: One thing that people have to realize is that these type of interfaces all work differently. I think that cable companies had to overcome when computer audio hit the market was... this stuff is all different than an S/PDIF cable. Which was really the only digital cable most of these companies had any experience with.
These interfaces all come with protocols which make not only the electrical aspect more demanding, but also details that are not apparent in S/PDIF cables.
"The turnaround time is the amount of time the cable settles to allow the other end to start transmitting without the signal being corrupted."
I would add one really key component to the list [time/timing errors/jitter]—what is called "turnaround". All of these protocols are asked for some kind of response. The turnaround time is the amount of time the cable settles to allow the other end to start transmitting without the signal being corrupted. It has to do with capacitance, length and impedance. For example some companies were making 50 foot USB cables stating they kept the capacitance low enough to make this work. I asked if they tested it on any asynchronous USB DACS and the answer was no. Well the problem was the host was never seeing the feedback pipe which made the DAC under or over run. The turnaround on these cables was sooooo long that when the DAC was asked to send the feedback pipe data that it was all corrupted when it reached the host.

 

AS: What about digital filters? How does a digital filter differ from an analog filter and doesn't this difference point to a digital "state" within the playback chain?


CH: As we have seen, "digital" itself is a very abstract concept. In the real world, there is some real physical quantity that represents "digital". For example, when the voltage exceeds such-and-such a threshold we define that as representing a "1".
But there is one place where our abstract concept (of the human brain) becomes (in a very strange way) tangible. And that is inside the electronic brain of a digital computer. Now the term "digital computer" can encompass a wide variety of things, from a simple gate that compares two signals to a sophisticated modern PC with billions of transistors operating at thousands of megaHertz.
When this electronic brain receives signals that represent 0's and 1's, it will carry out a very specific set of operations on those numbers as if they were really and truly digital. A good example of this is when one sees the image frequencies created by a digital sampling system. In the textbooks, these image frequencies repeat at multiples of the sampling frequency and go on forever -- to infinity and beyond!
This also happens inside the electronic "brain" that performs the computations, but as soon as the signal comes out into the real world, it has to conform to the real physical laws. For the image frequencies to continue forever, the impulses from the DAC chip would have to be infinitely narrow. Of course something infinitely narrow wouldn't exist. So a mathematician named Paul Dirac invented an abstraction called the "Dirac delta", where delta refers to a change. So it is an imaginary pulse that is infinitely narrow, but to have any energy it would also have to be infinitely tall. Of course such a thing cannot exist in the real world, but it exists in the equations created by digital mathematicians and calculated by the digital "brains" inside digital equipment.
As soon as that imaginary pulse comes out into the real world, the digital "brain" gives instructions to real switches that cannot change states with infinite speed. So they are stretched out to have a finite time, and this causes changes in the actual frequency response compared to the theoretical response.
But inside the "digital brain" of the equipment (and the brain of the digital engineer) is the only place that the signals are truly digital.
"But inside the "digital brain" of the equipment (and the brain of the digital engineer) is the only place that the signals are truly digital."


GR: When people ask me about digital filters I always have to remind them that most of the math we use here for digital filters was derived by the work of LaPlace and Fourier in the early 1800's. Remember to them, there was no computer. This math involves two tables, one of samples the other coefficients which make up the filters. A table with the audio data is multiplied by a table with the filter coefficients and accumulated to form a new output sample. LaPlace and Fourier therefore worked with infinite math models. Not 32 bit floating point, 24, 32, 64 fixed point math models. They assumed you had all the time in the world to do these computations, instead of in between two samples.
"...the larger you make the coefficient and the sample work into a larger model say 64, 72 bits or higher and don't over or under-run the math model, then the better it's going to sound."
This is why filters all sound different. A coefficient is less than 1, so it's a fraction. If you look at this as we do, then all the math here is fixed point, meaning there are no fractions. We multiply the coefficient by some factor, usually a multiple of 2, because we have to divide that out in the end to make the output sample correct. In fixed math it's faster and easier to divide by rotating the data right one spot (divide by 2) or 2 spots (divide by 4). But as Charlie has found out and something we were taught at school, the larger you make the coefficient and the sample work into a larger model say 64, 72 bits or higher and don't over or under-run the math model, then the better it's going to sound. Most commercial chips used 24 bit models for their math to make the chips cheaper. Some companies have really come around [and are building DAC chips with higher precision math models] and that is why the chips sound better and more realistic.


AS: To be continued...
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At best, this article is misleading. More likely, it is flat out wrong.

 

This article has already been linked to before in the various previous discussions on USB cables, and it is still grossly misguided, which has been pointed out in previous discussions. The article lacks a basic understanding of information theory, and perversely confuses (whether intentionally or not) discrete-time signal theory with digital data. It makes absurd claims like "digital is analog!"  when digital is discrete time and discrete amplitude, while analog is continuous in time and in amplitude.

 

If a USB cable meets the USB technical specifications, and the devices it connects conform to the technical specifications, then everything works as planned---identically to any configuration involving any other USB cable that also meets the USB specifications. If swapping USB-spec cables changes the integrity of the data transferred from one device to the next, then at least one of those devices (or cables!) is broken. If swapping USB-spec cables changes the integrity of the power transferred from one device to the next, then at least one of those devices (or cables!) is defective (or was exceedingly poorly designed).

 

USB cables (a) deliver audio data to a DAC (perfectly when operating within spec) and (b) deliver power to bus-powered devices (which DAC designers should account for USB spec's on power delivery).

 

Hope this helps clarify USB cables for audio applications.

 

Cheers

 

EDIT: Since this whole thread digressed into the technical details of USB audio and USB audio hardware (i.e., USB cables), it seems like a better place for this thread would be in the Sound Science forum. (duhn, duhn, duuuuuuuuuhn! I know, run and scream in terror! not sound science!)


Edited by ab initio - 2/12/14 at 11:53pm
post #38 of 191

How do i delete this? oh never mind :(


Edited by BadgerCow - 2/13/14 at 2:15am
post #39 of 191
Quote:
Originally Posted by ab initio View Post
 

EDIT: Since this whole thread digressed into the technical details of USB audio and USB audio hardware (i.e., USB cables), it seems like a better place for this thread would be in the Sound Science forum. (duhn, duhn, duuuuuuuuuhn! I know, run and scream in terror! not sound science!)

:eek:  I think the main problem is that it digressed away from USB cables, but you are right :bigsmile_face: .

(it seems we share a hobby :wink_face:).


Edited by jimmers - 2/13/14 at 2:19am
post #40 of 191

you just spared the public from another rant by me, containing (aside from the usb specs thing) 2-conductor wave propagation, fall/rise times, frequency dispersion and so on.

well played, seems like we are on the same wavelength :D

 

and no objections about the sound science thing. i love science (electrical engineer speaking here ;))

 

Quote:

Originally Posted by ab initio View Post

 

At best, this article is misleading. More likely, it is flat out wrong.

 

This article has already been linked to before in the various previous discussions on USB cables, and it is still grossly misguided, which has been pointed out in previous discussions. The article lacks a basic understanding of information theory, and perversely confuses (whether intentionally or not) discrete-time signal theory with digital data. It makes absurd claims like "digital is analog!"  when digital is discrete time and discrete amplitude, while analog is continuous in time and in amplitude.

 

If a USB cable meets the USB technical specifications, and the devices it connects conform to the technical specifications, then everything works as planned---identically to any configuration involving any other USB cable that also meets the USB specifications. If swapping USB-spec cables changes the integrity of the data transferred from one device to the next, then at least one of those devices (or cables!) is broken. If swapping USB-spec cables changes the integrity of the power transferred from one device to the next, then at least one of those devices (or cables!) is defective (or was exceedingly poorly designed).

 

USB cables (a) deliver audio data to a DAC (perfectly when operating within spec) and (b) deliver power to bus-powered devices (which DAC designers should account for USB spec's on power delivery).

 

Hope this helps clarify USB cables for audio applications.

 

Cheers

 

EDIT: Since this whole thread digressed into the technical details of USB audio and USB audio hardware (i.e., USB cables), it seems like a better place for this thread would be in the Sound Science forum. (duhn, duhn, duuuuuuuuuhn! I know, run and scream in terror! not sound science!)

post #41 of 191
Quote:
Originally Posted by ab initio View Post


At best, this article is misleading. More likely, it is flat out wrong.

This article has already been linked to before in the various previous discussions on USB cables, and it is still grossly misguided, which has been pointed out in previous discussions. The article lacks a basic understanding of information theory, and perversely confuses (whether intentionally or not) discrete-time signal theory with digital data. It makes absurd claims like "digital is analog!"  when digital is discrete time and discrete amplitude, while analog is continuous in time and in amplitude.

If a USB cable meets the USB technical specifications, and the devices it connects conform to the technical specifications, then everything works as planned---identically to any configuration involving any other USB cable that also meets the USB specifications. If swapping USB-spec cables changes the integrity of the data transferred from one device to the next, then at least one of those devices (or cables!) is broken. If swapping USB-spec cables changes the integrity of the power transferred from one device to the next, then at least one of those devices (or cables!) is defective (or was exceedingly poorly designed).

USB cables (a) deliver audio data to a DAC (perfectly when operating within spec) and (b) deliver power to bus-powered devices (which DAC designers should account for USB spec's on power delivery).

Hope this helps clarify USB cables for audio applications.

Cheers

EDIT: Since this whole thread digressed into the technical details of USB audio and USB audio hardware (i.e., USB cables), it seems like a better place for this thread would be in the Sound Science forum. (duhn, duhn, duuuuuuuuuhn! I know, run and scream in terror! not sound science!)

Oh no!
not the Sound Science Fiction (and amateur psychology) Forum!eek.gif
post #42 of 191
Quote:
Originally Posted by Skyyyeman View Post

BTW, I happen to agree with your earlier comments.  I've experienced significant differences between digital cables, including USB cables.

I think you have me mixed up with someone else who posted. I'm in the "if the USB cable is well made, there's no difference" camp. A $5 USB cable can often easily do the job.
post #43 of 191
It's amazes me how many people claim their approach as being scientific while talking about things they have never even tried but could easily do so at virtually no cost to themselves.

Do remember that science also said that the earth is flat and that humans can't hear beyond 20kHz. And CD's are perfect sound forever. Perhaps sending my music over bluetooth is just as good as a coax spdif cos digital is digital.

Shouldn't one approach things with curiosity rather than prejudice? Anyway, it's comforting to know there are members here who already know everything.
post #44 of 191
Quote:
Originally Posted by x838nwy View Post

It's amazes me how many people claim their approach as being scientific while talking about things they have never even tried but could easily do so at virtually no cost to themselves.

Do remember that science also said that the earth is flat and that humans can't hear beyond 20kHz. And CD's are perfect sound forever. Perhaps sending my music over bluetooth is just as good as a coax spdif cos digital is digital.

Shouldn't one approach things with curiosity rather than prejudice? Anyway, it's comforting to know there are members here who already know everything.


You do realize that there are actually people who have read the USB specifications and data sheets for the usb chipsets, and who know the fundamentals of electric and electronic circuits and information theory from their undergraduate engineering education.

 

A famous quote that is frequently attributed to Sir Isaac Newton is

Quote:
 If I have seen further it is by standing on the shoulders of giants
-Sir I. Newton [1]

What he is saying, is that his advances in science are possible only by virtue of the body of knowledge established by his predecessors. This is an important concept that only a few people seem to grasp; namely, we don't have to reinvent the wheel every time we want to invent a chariot, wagon, train, or car. Furthermore, once we establish a principle like "round wheels roll", we can use wheels---without reinventing them from first principals--- to build many cars. The previous scientific advancements in the field of semiconductors, quantum mechanics, E&M field theory, etc. are already established; hence, we can move forward and do things like make devices that communicate using USB cables.

 

USB is not at the forefront of the scientific frontier. If you're interested in that, look at things like quantum computing. Don't project your own personal lack of understanding of the topic onto the rest of the world. The one who is unscientific is the one who chooses to disregard the body of overwhelming existing knowledge on all the principles at play (not only in USB audio devices, but everything) but bases one's beliefs in unfalsifiable claims or falsifiable claims for which no evidence is presented.

 

Finally, I just want to correct some of the inaccuracies in the post above. CD audio is encoded as a pulse code modulation data stream with a bandwidth that encompasses the range of average human hearing. It is capable of fully encoding the information in this audible range with a worst-case-secnario dynamic range of 96 dB (and at most frequencies, can be much more with correct use of noise-shaped dithering). This data can be transferred over digital communication interfaces with sufficient data bandwidth (1,411.2 kbit/s, such as usb, spdif, etc.) without loss of information. Therefore, any player on the receiving end can recreate the audio sent via these interfaces with precision limited only by the capabilities of the device.

 

On the other hand, bluetooth audio is subject to the AD2P profile and is limited by the available bandwidth to less than 768 kbit/s. Naturally, audio information cannot be sent at maximum fidelity. Instead, lossy audio compressing is used to fit the stereo audio information in this limited bandwidth and places a limit on the fidelity of the resulting audio stream on the receiver's end. Therefore, no, "bluetooh is not as good as CD, spdif, etc." as the previous poster postulated.

 

I hope everybody can learn a little bit from the information in the post!

 

Cheers

post #45 of 191
Quote:
Originally Posted by ab initio View Post


You do realize that there are actually people who have read the USB specifications and data sheets for the usb chipsets, and who know the fundamentals of electric and electronic circuits and information theory from their undergraduate engineering education.

A famous quote that is frequently attributed to Sir Isaac Newton is
What he is saying, is that his advances in science are possible only by virtue of the body of knowledge established by his predecessors. This is an important concept that only a few people seem to grasp; namely, we don't have to reinvent the wheel every time we want to invent a chariot, wagon, train, or car. Furthermore, once we establish a principle like "round wheels roll", we can use wheels---without reinventing them from first principals--- to build many cars. The previous scientific advancements in the field of semiconductors, quantum mechanics, E&M field theory, etc. are already established; hence, we can move forward and do things like make devices that communicate using USB cables.

USB is not at the forefront of the scientific frontier. If you're interested in that, look at things like quantum computing. Don't project your own personal lack of understanding of the topic onto the rest of the world. The one who is unscientific is the one who chooses to disregard the body of overwhelming existing knowledge on all the principles at play (not only in USB audio devices, but everything) but bases one's beliefs in unfalsifiable claims or falsifiable claims for which no evidence is presented.

Finally, I just want to correct some of the inaccuracies in the post above. CD audio is encoded as a pulse code modulation data stream with a bandwidth that encompasses the range of average human hearing. It is capable of fully encoding the information in this audible range with a worst-case-secnario dynamic range of 96 dB (and at most frequencies, can be much more with correct use of noise-shaped dithering). This data can be transferred over digital communication interfaces with sufficient data bandwidth (1,411.2 kbit/s, such as usb, spdif, etc.) without loss of information. Therefore, any player on the receiving end can recreate the audio sent via these interfaces with precision limited only by the capabilities of the device.

On the other hand, bluetooth audio is subject to the AD2P profile and is limited by the available bandwidth to less than 768 kbit/s. Naturally, audio information cannot be sent at maximum fidelity. Instead, lossy audio compressing is used to fit the stereo audio information in this limited bandwidth and places a limit on the fidelity of the resulting audio stream on the receiver's end. Therefore, no, "bluetooh is not as good as CD, spdif, etc." as the previous poster postulated.

I hope everybody can learn a little bit from the information in the post!

Cheers

Oh noes. You mean there'a spec?? No Way!!!

The body of knowledge of which you apparently possess is merely a basis for hypotheses. Your is that a usb cable as long as it is functional, cannot have any influence in the final reproduced sound. The science happens when you go test that hypothesis. Sir Issac, the man you quoted, would not have just put two and two together and claimed that it works without testing it. You quote engineering facts but it seems you do not know how to make the most of those facts.

Would it be too much to get yourself a few usb cables to try and return them all if you find you are right? Why keep dragging on about nothing but assumptions? I grant you they are based on a few facts, but you should know well that it is never possible to consider ALL the facts and an assumption is just a polished guess until it is proven.

As for the bt specs, bt 2.o can do 2Mbits/sec. Your figures are for v.1.2.

And what does reading the specs. Have to do with making good cables? We've known audio rca interconnect specs. For ages. Heck we've known about tubes and transistors for decades but amps are still getting better and better. Shockingly without using any alien tech or anything. By your logic, that should not be possible.
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