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Dilemma: Should I not believe any reviewers who talk about cables or just ignore that section of... - Page 116

post #1726 of 1790

Why ask for an opinion on an opinion? Get two cables that supposedly sound different and hook them up to something recognized to be very revealing by subjectivists and see what you think. If your hear a difference, and it mimics a review, you've got someone to trust. If you don't, you've saved some money. Of course, you can believe more strongly in placebo than your ears and your objectivity in which case you should just go and watch TV.biggrin.gif

post #1727 of 1790
http://www.audiostream.com/content/draft

"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.



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.
post #1728 of 1790

So are you trying to imply now that cables cause digital audio jitter?

 

 

edit:

 

There sure is some nonsense in that article, such as applications sounding different, saying that the cause of glitches with DACs is a cable of poor quality (it's usually DPC latency or other software related issues, but I agree that if there are cable problems it causes plainly audible glitches), again the confusion of jitter of transmission and D/A conversion, the attempt at making data transmission look like sorcery, ..

 

They are right that most cable companies had no idea how to properly build digital cables to spec, and some of them still don't, but that doesn't stop them from selling them for hundreds of dollars.

 

50 foot USB cables: of course they will cause problems, they are not built according to the USB spec.

 

... stopped reading when they started talking about the "digital brain".


Edited by xnor - 7/12/13 at 5:45pm
post #1729 of 1790
Jitter as it occurs in even the cheapest home audio equipment is as much as 100 times below the threshold of perception. You aren't hearing jitter with human ears.

deja vu
http://www.head-fi.org/t/668878/jitter-correlation-to-audibility/30
Edited by bigshot - 7/12/13 at 5:52pm
post #1730 of 1790
Quote:
Originally Posted by Happy Camper View Post


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.

This IS where it gets miscontrued. Of course the signal in a cable is analog. The way he say that is very misleading. The way he is trying to tweak people minds... See, even a square wave that is REALLY distorted, something that would sound aweful if it where an audio analog signal is still seen on the other side of an analog digital signal transmission as a 1.

Ok, that is very simply said. (The faster you try to push data, the more important the cable gets. For instance, a cable bus extension system for a PCIe bus x8 can only be about 2 feet long, and that only using fat redrivers. A PCIe x16 signal will have a possible transmit length of 12 inches in a well calculated trace before it needs redrivers, jitter cleaners, reclocking, buffers et cetera) (At those PCIe speeds, all the traces need to be the same length even, so the data arrives simultaniously. This is why, on motherboards for instance, you sometimes see traces that are looping around all over, instead of just a straight short line to the slot.

None of the PCIe stuff applies to USB audio, as USB audio is sooooo vevryyy slooooow. But a smart manufacturer of audio cables could twist the trace length idea, and offer usb cables that have exact tolerances length wise, and state how this perfect matching enables much better clarity, timing and rythem because all the digital signals are arriving at the proper instant in the total time domain.... Ya know? Send me money I'll build you one,




Another example. Analog audio in a cable is like you talking on a phone. (bear with me here) If you talk and say onethousandandone and the connection is really bad, the other person won't understand it. It might have breakups or it is just impossible to understand beacuse the audio quality is so bad.

Now, in a digital transmission, think of it like this: A 1 is a minute long beeep tone of a high frequency, and a 0 is a minute long beep of a middle frequency. If you have a really REALLY bad connection, the other person can still reconstruct the 4 minute transmission fully. Then he can reconstruct the analog signal and can say out loud: One thousand and one in perfect audio quality.

If nobody understand anything at all, then use smoke signals. smily_headphones1.gif
Edited by ev13wt - 7/12/13 at 7:16pm
post #1731 of 1790
Quote:
Originally Posted by Happy Camper View Post

CH: An ANALOG signal!
 

 

This is incorrect. A digital signal is not the same as an analog signal.

 

An analog signal contains infinite information in the instantaneous amplitude of the signal and for an infinite number of instances in time. Think of this as infinite bit depth at infinite sampling rate.

 

A digital signal is limited in both the amplitude resolution and the temporal resolution. Namely, the information can only take on a limited number of discrete values at discrete times.

 

In the case of the (serial) transmission of binary data in a wire (let's call it the transmission wire), there are two things that are important: 1) the sampling rate and 2) the voltage threshold between a "high" and a "low" value (let's call this V_thresh)

1) the sampling rate is usually determined by a parallel wire (or differential wire pair) that sends a clock signal. Only the master device would send the clock signal, and it would provide the timing reference for the slave device. Usually, the rising edge of the clock signal tells the slave device to sample the voltage on the transmission wire.

2) when the device samples the voltage on the transmission wire, it asks whether or not the voltage is greater or less than V_thresh. if the voltage at that instant is greater than V_thresh, then that bit was a "high" or a 1. if the voltage at the instant of sampling is less than V_thresh, then the bit is a "low" or a 0. The exact shape of the voltage signal is irrelevant to the transmission of data. Either the voltage on the transmission wire is greater than the threshold value, or it isn't.

 

I hope this helps clear up the issue smily_headphones1.gif

 

some links:

Wiki "digital signal"

Wiki "analog signal"

 

Cheers!

post #1732 of 1790
So a cable manufacturer and two DAC designers give their views and you guys all pick them apart.

Cables have an effect on what we hear. To those reading this, they have information both for and against. They get to choose.

Debate class dismissed (bye).
post #1733 of 1790

Happy camper -and so  is the digital and analogue design of my very expensive  audio equipment bought from Cyrus Audio a well known and highly thought of company in the UK . Run not by business men but by digital design engineers and analogue design engineers  which is OWN designed and OWN built and that includes the disc platform with minute amounts of jitter. Seemingly they are wrong.I hope they will email the company to tell them they are "doing it wrong" And contrary to the thinking about me I am not 100 % convinced about cables but when 2 -6 inches of connecting wire are twisted together my Wayne Kerr LCR meter tells me its --13 PF.But that doesn't matter does it?

post #1734 of 1790
Quote:
Originally Posted by Happy Camper View Post

So a cable manufacturer and two DAC designers give their views and you guys all pick them apart.

Cables have an effect on what we hear. To those reading this, they have information both for and against. They get to choose.

Debate class dismissed (bye).

Wait a minute. The company I work for designs software defined radios using high speed dacs and adcs for military use. Just saying. I'm no engineer by any stretch, but I do understand the basics.

Nobody here is picking anything apart, we are just filling in the blanks that they left out (intentionally to fool you). If you don't want to see the entire picture, feel free to believe in the easter bunny if you wish - but don't get all huffy and puffy about it. It seems you had your opinion formed even before entering this thread. Why can't you just understand that other people have a different view than your (obviously technically limited) view?
Edited by ev13wt - 7/13/13 at 5:36am
post #1735 of 1790
Quote:
Originally Posted by Happy Camper View Post

So a cable manufacturer and two DAC designers give their views and you guys all pick them apart.

It doesn't matter who these guys are but what they are saying, unless you don't understand what they are saying, then you kinda have to put faith in them that what they are saying is right because of who they are.

 

 

Quote:
Cables have an effect on what we hear. To those reading this, they have information both for and against. They get to choose.

Homeopathy (placebos) also has an effect on some people. It's considered a "sham" and "quackery".

 

Reality just is, you cannot choose it away. You cannot choose that you believe you can fly, nor that you will be able to hear differences in a blind test. All you can choose is to fool yourself in an uncontrolled comparison.

post #1736 of 1790
The difference is, there isn't a buy it now button and an order form under what we say.
post #1737 of 1790

Bob Carver---Not an audio design engineer but a physicist --a man who  uses the words like Holistic and many more which would get him banned on this forum--an American who is on many website lists as "one of the all time great audio designers" ---Who's equipment is listed in many audio websites as  some of the "all time best audio amps in the World"..In many "top tens" lists. A man who goes not by straight line science but takes into account that people listen to music with  human ears not a frequency response meter--level bridge--spectrum analyzer or THD meter.Sadly "fails" at the first post here.OH well maybe he should go back to university and learn more so that he is up to the "equivalent" here. 

post #1738 of 1790

What makes you think human perception isn't part of sound science? Carver has been discussed here many times. He's the one that proved that solid state amps can be adjusted to sound like tube amps by just coloring the output in the proper way.

 

Sound Science folks are the ones saying that the specs of solid state components are so good today, even the cheapest CD player exceeds our ability to hear. The ones who point to infinitely small numbers and claim they make a difference are the subjectivists.

post #1739 of 1790
Quote:
Originally Posted by duncan1 View Post

Bob Carver---Not an audio design engineer but a physicist --a man who  uses the words like Holistic and many more which would get him banned on this forum--an American who is on many website lists as "one of the all time great audio designers" ---Who's equipment is listed in many audio websites as  some of the "all time best audio amps in the World"..In many "top tens" lists. A man who goes not by straight line science but takes into account that people listen to music with  human ears not a frequency response meter--level bridge--spectrum analyzer or THD meter.Sadly "fails" at the first post here.OH well maybe he should go back to university and learn more so that he is up to the "equivalent" here. 


Failing to see your point.  Did you leave off a conclusion?

 

This is the same Bob Carver that made his $400 amp mimic a huge and expensive tube amp.  Later made his own huge and expensive tube amp.  A man who uses plenty of instrumentation.  Where you got the idea Mr. Carver was all into this gestalt of holistic listening was probably reading some of those "trust our ears" based magazines when they reviewed his equipment or interviewed him.  You definitely picked the wrong guy as an example of someone not going by "straight line science". 

 

Why do you think a man who successfully replicated sound of a $10k+ tube amp with $400 solid state amp later made such very expensive amps himself?  I think there lies a clue there.

post #1740 of 1790

Bob Carver built equipment that put it up against  many well thought of audio equipment. His  sounded good to the human ear  not specifically to scientific measurement there is a difference as this thread disputes and discounts the "human" side of things in audio  only allowing purely electronic view points to be the accepted thing. It seems to be a case of "self denial" that we are human and that humans can do what robots cant and that's FEEL the music. Its an illogical fact and something that robots will never achieve. No robot can hear of feel the "spirit in music".and never will because they can never get beyond logic. It is non productive  to constantly "put down" human beings because they can hear more in music than a piece of electronics can. That's patronizing  and only has a basis in non human electronics  .Science is made to assist man not "standards" which are based on machines. There is no "standard" human beings some people get diseases that others don't and not because they don't eat such and such to make them ill but because their whole DNA  is different from person to person. Rules were made for man not man for rules. Science is not perfect and is a long way from being so so it isn't a "standard" on which to judge human beings.They keep on getting it wrong viruses   change and build up defenses to anti biotics .Humans change from generation to generation in a biological sense . But electronics no matter how good can never compete no matter how many SF films Hollywood throws out.. So if some people can hear differences in audio equipment it doesn't mean it doesn't exist because others don't. Our perception is different from person to person.And even though I cant hear all the things that are said I don't put down others that say they do. Capacitance/inductance/ resistance in connecting wires /active components all "gang up" to make it harder to design a stable and low distortion power amp. What works just fine on a bread board can oscillate to -ell in a beautiful PCB .I proved this by building a power amp whose components were "squashed together" just the high current output kept at a distance and I didn't need a compensation cap---but it looked Terrible.        

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