Article: My Lying Ears

[mansr]

If the cables have been plugged in a while, of course it will sound different. The contacts corrode slightly over time, and reseating them produces a better contact. There is nothing controversial about that.

 

This is true for analogue cables, or at least it can be if corrosion is bad enough (gold-plated contacts in a typical home environment don't corrode much). For digital cables, if the bits get through unmolested, they sound the same even if the contacts are not perfect. There is nothing controversial about that.

[Paul R]

This is true for analogue cables, or at least it can be if corrosion is bad enough (gold-plated contacts in a typical home environment don't corrode much). For digital cables, if the bits get through unmolested, they sound the same even if the contacts are not perfect. There is nothing controversial about that.

 

Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

 

It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

 

Even given all of which, it is very doubtful that much if any audible change happens because of such noise in most systems and in most cases.

 

-Paul

[Sal1950]

Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

 

It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

 

Even given all of which, it is very doubtful that much if any audible change happens because of such noise in most systems and in most cases.

 

-Paul

If you have even the most basic decent DAC, timing and jitter errors are a non-issue

[jabbr]

If you have even the most basic decent DAC, timing and jitter errors are a non-issue

 

Really? You know this?

[xyzzy1]

Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

 

It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

 

Even given all of which, it is very doubtful that much if any audible change happens because of such noise in most systems and in most cases.

 

-Paul

 

I would add that electric distortions caused by all cables including digital cables leach out into the analogue circuitry as well not just the dac.

 

If the analogue amp is not well shielded/isolated from this electrical noise its analogue reproduction is affected.

 

If you know about electrical engineering than you would know isolating electrical noise from leaching to out all the electronic components is a science/engineering effort onto itself. Its not as simplistic as 1's and 0's as you guys seem to keep espousing.

[The Computer Audiophile]

If you have even the most basic decent DAC, timing and jitter errors are a non-issue

Said nobody ever ... oh wait you just did.

 

Your opinion is fairly popular actually. I disagree with it based on my experience and discussions with digital audio engineers. That said, if we all agreed this place could get boring :~)

[Jud]

Really? You know this?

 

It helps if you define "even the most basic decent DAC" as one where timing and jitter errors are a non-issue.

 

There are lots of folks who think it is the DAC's job to be immune to incoming nastiness, and therefore if it's not, it's not a good DAC. The Benchmark DACs are often cited as examples of such immune DACs.

[xyzzy1]

This is true for analogue cables, or at least it can be if corrosion is bad enough (gold-plated contacts in a typical home environment don't corrode much). For digital cables, if the bits get through unmolested, they sound the same even if the contacts are not perfect. There is nothing controversial about that.

 

Same as I replied to the other poster:

Electric distortions caused by all cables including digital cables leach out into the analogue circuitry as well not just the dac.

 

If the analogue amp is not well shielded/isolated from this electrical noise its analogue reproduction is affected.

 

If you know about electrical engineering than you would know isolating electrical noise from leaching to out all the electronic components is a science/engineering effort onto itself. Its not as simplistic as 1's and 0's as you guys seem to keep espousing.

 

You guys do realize that the 1's and 0's are determine by voltage rise and fall and it takes a number of electrical compontents to do the trnasformations and its not some magical smooth floating highways where the 1's and 0's are delicately wafted on pillows to the other side?

[xyzzy1]

It helps if you define "even the most basic decent DAC" as one where timing and jitter errors are a non-issue.

 

There are lots of folks who think it is the DAC's job to be immune to incoming nastiness, and therefore if it's not, it's not a good DAC. The Benchmark DACs are often cited as examples of such immune DACs.

 

If there is an electrical wire connecting components there is no such thing as "immune DACs" or any other electrical component.

There are only better engineering attempts to try to isolate noise. There are many upper end dacs that do a much better job than benchmark (which is good at its price point). Basic understanding is really lacking in a lot of this discussion...

[Sal1950]

Really? You know this?

Yes, the science and the measurements show us so. :-)

Bits is Bits after all.

[Paul R]

If you have even the most basic decent DAC, timing and jitter errors are a non-issue

 

Eh - no. Especially with the most basic DACs, timing and jitter errors are most problematic.

 

That is not to say you need spend megabucks to be rid of the issues with a DAC, but the idea of spending $100-$200 on a DAC is horrifying to some folks.

 

Even in some rather expensive DACs, electrical noise can creep in over the cable connections, and some folks can definitely hear when this happens. It's why adding a clean power supply may improve the sound of a unit. (Though that is far from a universal truth, it is rather common.)

[mansr]

Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

 

It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

 

Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

 

As some people have pointed out, a digital cable can carry (analogue) electrical noise from one component to another, and this is perfectly true. However, this problem is not solved by cleaning the contacts.

[Paul R]

Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

 

As some people have pointed out, a digital cable can carry (analogue) electrical noise from one component to another, and this is perfectly true. However, this problem is not solved by cleaning the contacts.

 

Um- actually, yes it can be. Or at least part of the issue can be. It's pretty common to clean the contacts on cables and hear a difference.

 

A local clock does not solve the problem of time shift when detecting signal from noise floor when the noise floor is varying from additive electrical noise. It helps, sure, but it does not solve it.

 

Again, how much of an impact it actually has on the sound is not what I am speaking of.

[The Computer Audiophile]

Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

This is the opposite of what all the measurements tell us.

[jabbr]

Yes, the science and the measurements show us so. :-)

Bits is Bits after all.

 

Well "timing issues" and jitter are both measurable quantities so what so called "science" tells you that the measurements don't matter -- seriously?

[xyzzy1]

Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

 

As some people have pointed out, a digital cable can carry (analogue) electrical noise from one component to another, and this is perfectly true. However, this problem is not solved by cleaning the contacts.

 

 

Not solved, but it does reduce it for the noise introduced by the degraded contact.

 

So if you/folks accept that degraded contacts cause noise why is it controversial that poor quality copper with impurities would cause noise for the same reaspons (something the impeeds the flow of electrons)? And yes. ringing, eddy currents, noise on the electrical signal from poor quality wire is measureable on very sophisticated equipment.

[Sal1950]

This is the opposite of what all the measurements tell us.

 

So you have measurments of who's DAC that shows the reclocking method was ineffective and the jitter still exists at some audible level, whatever that is?

[mansr]

Not solved, but it does reduce it for the noise introduced by the degraded contact.

 

So if you/folks accept that degraded contacts cause noise why is it controversial that poor quality copper with impurities would cause noise for the same reaspons (something the impeeds the flow of electrons)? And yes. ringing, eddy currents, noise on the electrical signal from poor quality wire is measureable on very sophisticated equipment.

 

Human ears are not "very sophisticated equipment."

[The Computer Audiophile]

So you have measurments of who's DAC that shows the reclocking method was ineffective and the jitter still exists at some audible level, whatever that is?

I suggest looking at all Stereophile measurements of jitter for all reviewed DACs. It's a starting point.

[xyzzy1]

Human ears are not "very sophisticated equipment."

 

Really?!?! You sit in an sound isolated room looking at any "equipment" you want. I'll stand in the room where the musician is playing blindfolded. Lets see see who can identify what instrument is being played first.

 

Don't discount your ears and their abilities. Your ears have their own abilities not matched by any current "measuring equipment".

 

And like what any athlete does, you can improve your discerning ability by listening to a lot of good audio equipment, just as you can get better at doing three point shots. And yes, a lot of folks will never make the “three point shot” with their ears.

[Jud]

I suggest looking at all Stereophile measurements of jitter for all reviewed DACs. It's a starting point.

 

To be fair, those measurements don't show what the cause of the DAC's jitter was - whether it was jitter at the input (mansr is right that asynchronous inputs where the DAC's clock governs should eliminate this as a *direct* cause); electrical noise at the input; something at the input causing electrical noise in the DAC's own circuitry; or any of several other, sometimes contradictory factors. (Regarding "sometimes contradictory," I'd offer as one example certain optical isolators that keep electrical noise generated outside the DAC from getting into the DAC, but at the cost of generating a fair amount of electrical noise in the DAC itself in the process of optical-to-electrical conversion.)

[Jud]

Human ears are not "very sophisticated equipment."

 

That critically depends on the question "For detection of what?" If the answer is some type of pattern matching, human ears combined with human brains are very often superior to even the best sensors and computers. On the other hand, if the answer is "a signal at -120db," then a sensor and computer can do a superior job.

[xyzzy1]

If the cables have been plugged in a while, of course it will sound different. The contacts corrode slightly over time, and reseating them produces a better contact. There is nothing controversial about that. Now, Quantum Tunneling cables, those are much more debatable.

 

Yea it would be. I not one for marketing terms.

 

But... on entry level high-end audio systems on up differences in cables can be night and day and sometimes not.

From lampcord to Kimber 4tc is night and day on even an entry level high end audio system.

 

I've done this many times for many friends who took a dip into high-end audio. The differences are not subtle.

You don't need to "match the volume levels and have read all the self-serving research that says it doesn't... blah blah".

If you guys need a double blind test to tell from night from day then let the endless discussion rage on this site as it does.

 

But it does show that you guys haven't bothered to listen to a high end audio system and are having discussions in a vacuum.

 

Just remember, "In theory, theory and practice are the same. In practice, they are not."

A saying from a REAL scientist that is as great as his equations….

[Jud]

I've done this many times for many friends who took a dip into high-end audio. The differences are not subtle.

You don't need to "match the volume levels and have read all the self-serving research that says it doesn't... blah blah".

If you guys need a double blind test to tell from night from day then let the endless discussion rage on this site as it does.

 

But it does show that you guys haven't bothered to listen to a high end audio system and are having discussions in a vacuum.

 

 

I've experienced what I believe to be very audible differences from changing cables. That said, volume levels absolutely need to be matched for any valid comparison.

 

People are *very* sensitive to volume levels. There was a blind test conducted here a few years ago with the assistance of the head of the BIS recording company, with versions of the same track ranging in resolution from mp3 to either 96/24 or 192/24, or both (forget which at the moment).

 

The overwhelming winner was a RedBook file with a 1dB higher volume level.

[xyzzy1]

I've experienced what I believe to be very audible differences from changing cables. That said, volume levels absolutely need to be matched for any valid comparison.

 

People are *very* sensitive to volume levels. There was a blind test conducted here a few years ago with the assistance of the head of the BIS recording company, with versions of the same track ranging in resolution from mp3 to either 96/24 or 192/24, or both (forget which at the moment).

 

The overwhelming winner was a RedBook file with a 1dB higher volume level.

 

 

I would ask who where the subjects that did the listening and selection of whats "better"?

We could prove 3 point shots are impossible except for random chance by bringing in random people off the street.

 

There are many of tests done with/by folks who have background in listening to high-end audio where subjective discrimination between sampling rates, cables, amps, etc, was done accurately and I agree matching volume levels is par for the course if you are experienced with this evaluation. (And I would argue the discrimination is "objective", because the participants are experienced with listening, we hope :-) )

 

So, a nit, but experience, I think, is more the proper asset for these types of audio "lab" test / evaluation rather then matching volume levels.