It’s All a Preference

[jkeny]

I don't know. First you have to show, with measurements, that there is a noise, at 21Khz, then that is folding down into the audible range, then that the amplitude of the noise is high enough relative to the music to be audible. Get all that, and you've got evidence. If it's strong enough, it's acceptable on its own. If it is on the edge of audible, you'll need to confirm it with blind listening. Short of that? Speculation. Or to use your words, theory. I withdraw the adjective "wild."

Tim

Come on Tim, you are really reaching now. I don't have to show anything - I'm giving you an example of how your statement is incorrect - you are avoiding, deflecting & obscurating at every turn.
Measurements & blind test do not come into it!

I'll re-quote what you said

You're speculating, rather wildly I might add, about the possibility that linear noise, inaudible when no music is playing, can somehow attach itself to the signal and become audible, non-linear distortion when music is playing. I've never seen any evidence of this.

Are you still maintaining this?

 

[JackD201]

Distortions intrinsic to the signal are always audible. There is a difference between something being audible and something being distinguishable or immediately identifiable for example dither used in the ADC process. The problem is when we are talking about the material itself, there is no way you can take out these distortions/noise. We simply accept the material as what it is and are left with a spectrum of lousy to excellent recordings.

When we get to the playback end which will and does introduce distortions of their own, we users have a tiny bit of control. Fidelity is an ideal. It is not a reality at this point in time.

In my opinion, audibility is its crutch, its rationalization because given the first paragraph I see a gaping hole in the logic as noise is treated as an independent variable which it isn't as far as the signal is concerned.

Finally and this one is a big one, not all noise is bad!

 

[Robh3606]

So are you trying to tell me that these noise sources have exactly the same effect in digital systems as they do in analogue playback?

Hello John

Well from a consumer standpoint does it really matter?? They are all well known sources of noise and can be shielded against or mitigated through good design. These are all known and have been for quite some time. There may be different mitigation strategies but are the effects not well understood??

No we can't. I would refer you to reading Amir & Donh postings in this forum on jitter to understand what it's audible effects a

They are both objectionable even though the audible effects may differ. So even though they may be unique to each media type the results are a diminished listening experience if either one is present past the magic threshold. The issue being what exactly that threshold is.

Is this pre-echo the same as what is created by certain interpolation filters?

I would think not. One is a mechanical issue the other electrical/temporal I presume if I understand the digital side correctly. One sounds easy to mitigate through the disk mastering process the other not so once the filters are designed in. I have never heard of digital pre-echo. If it sounds anything like analog pre-echo I can’t remember ever hearing it in digital media.

As far as distortion is concerned you should read Earl Geddes papers on it. Basically it questions how useful our traditional distortion measurements are as far as audibility. Good read

http://gedlee.com/distortion_perception.htm


Rob

 

[Phelonious Ponk]

Come on Tim, you are really reaching now. I don't have to show anything - I'm giving you an example of how your statement is incorrect - you are avoiding, deflecting & obscurating at every turn.
Measurements & blind test do not come into it!

I'll re-quote what you said Are you still maintaining this?

Right up to the moment that you show me the evidence, yes.

Tim

 

[jkeny]

Hello John

Well from a consumer standpoint does it really matter?? They are all well known sources of noise and can be shielded against or mitigated through good design. These are all known and have been for quite some time. There may be different mitigation strategies but are the effects not well understood??

So you have gone from a position of "Well what are the issues" to one where they don't matter anyway??? I know the competently designed statement covers all eventualities - it is the perfect get-out clause. If I saw this on an insurance policy I would run away from the obvious scam that it is. The world would be perfect place if everything was "competently designed" - problem is nobody will ever give a definition of exactly what competently designed means.

They are both objectionable even though the audible effects may differ. So even though they may be unique to each media type the results are a diminished listening experience if either one is present past the magic threshold. The issue being what exactly that threshold is.

I've already stated how this type of noise manifests is through edginess & sibilant distortion. If you have never heard these issues then you are unaware of them. Tim's "magic threshold" seems to be breached everyday as he expects to hear sibilant distortion in his digital audio. Actually Tim points to something that is worth mentioning, there are a lot of people who prefer this distortion & think that it is the true sound of digital - uber-detailed & incisive. It's the equivalent of MSG in your food - it unnaturally enhances flavour to the extent where the natural subtlety of taste has disappeared. It ultimately results in a headache - much the same as the digital distortions I'm talking about.

So you can see we are talking about distortions that are woven through the audio, like MSG in food, not like scratches & pops that are easily distinguishable from the music!

I would think not. One is a mechanical issue the other electrical/temporal I presume if I understand the digital side correctly. One sounds easy to mitigate through the disk mastering process the other not so once the filters are designed in. I have never heard of digital pre-echo. If it sounds anything like analog pre-echo I can’t remember ever hearing it in digital media.

You are being too literal here - you expect to hear a diminished echo of the sound just before the actual sound - as you do in analog. This is not the what you will hear in digital as the pre-echo is so close to the actual sound - I hear it as a dulling of the transients - a time smear!

As far as distortion is concerned you should read Earl Geddes papers on it. Basically it questions how useful our traditional distortion measurements are as far as audibility. Good read

http://gedlee.com/distortion_perception.htm


Rob

Yes, thanks I read them a while ago but will renew my acquaintance again

 

[Robh3606]

You are being too literal here - you expect to hear a diminished echo of the sound just before the actual sound - as you do in analog. This is not the what you will hear in digital as the pre-echo is so close to the actual sound - I hear it as a dulling of the transients - a time smear!

Hello John

How close is close?? A mil sec??

I know the competently designed statement covers all eventualities - it is the perfect get-out clause. If I saw this on an insurance policy I would run away from the obvious scam that it is. The world would be perfect place if everything was "competently designed" - problem is nobody will ever give a definition of exactly what competently designed means.

It's not a get-out clause. People do it everyday. They make decisions based on their experience and knowledge on every product that comes to market. I bet if you chalenged someone about their choices they would have a very complete list of compromises made and why they made the choices they did. I work in a place where we have design reviews and you get to do it internally and then in front of your customers and usually theirs as well. It's a High Reliability Space and Military enviornment where they go down to the individual part choices during the design reviews. So please don't say that professionals don't know what that means.

You are a manufacturer no?? You don't think your products are "competently designed"?? You don't know what it means??

Rob

 

[Soundproof]

The jitterbug is on, I understand.

In another thread I deviously referred to the size of Betelgeuse relative to a human to indicate the scale to picoseconds. But here's an analogy that's a lot more fun, from a Letter to the Editor in The Absolute Sound, responding to a review where the fact that a DAC was able to reduce jitter by seven picoseconds was hailed as a major breakthrough worthy of acquisition.

The writer used issues of TAS as a starting point, and had found that they on average had 71 sheets. He suggested that the issues should be placed cover to cover, spine up, around the Equator, to create a band of TAS that spanned the globe.
This band, that ran the entire circumference of the planet, at the Equator, was to represent one entire second of time. The band would consist of approximately 400 million issues of TAS.

How many issues of TAS would represent 7 picoseconds?

3 (three) sheets of 1 (one) issue of TAS would represent 7 (seven) picoseconds.

 

[jkeny]

Hello John

How close is close?? A mil sec??

Look up almost any DAC datasheet & look at group delay - it will be given in samples - you can work it out in milliseconds, I'm sure

It's not a get-out clause. People do it everyday. They make decisions based on their experience and knowledge on every product that comes to market. I bet if you chalenged someone about their choices they would have a very complete list of compromises made and why they made the choices they did. I work in a place where we have design reviews and you get to do it internally and then in front of your customers and usually theirs as well. It's a High Reliability Space and Military enviornment where they go down to the individual part choices during the design reviews. So please don't say that professionals don't know what that means.

You are a manufacturer no?? You don't think your products are "competently designed"?? You don't know what it means??

Rob

Ah yes the Miltary environment has got a handle on defining levels of performance right down to the part level - they have a defining document which outlines the expected performance right down to the part level. I even buy some of these parts at times called Mil-spec.

Please show me an equivalent set of standards or documents for the audio industry or even give me a robust definition of "competently designed".

 

[Phelonious Ponk]

The jitterbug is on, I understand.

In another thread I deviously referred to the size of Betelgeuse relative to a human to indicate the scale to picoseconds. But here's an analogy that's a lot more fun, from a Letter to the Editor in The Absolute Sound, responding to a review where the fact that a DAC was able to reduce jitter by seven picoseconds was hailed as a major breakthrough worthy of acquisition.

The writer used issues of TAS as a starting point, and had found that they on average had 71 sheets. He suggested that the issues should be placed cover to cover, spine up, around the Equator, to create a band of TAS that spanned the globe.
This band, that ran the entire circumference of the planet, at the Equator, was to represent one entire second of time. The band would consist of approximately 400 million issues of TAS.

How many issues of TAS would represent 7 picoseconds?

3 (three) sheets of 1 (one) issue of TAS would represent 7 (seven) picoseconds.

Perfect. I'm guessing "pre-echo" is every bit as devistating a problem.

Tim

 

[jkeny]

Perfect. I'm guessing "pre-echo" is every bit as devistating a problem.

Tim

Tim, don't get me wrong, you guys perform a great service to the audio industry - otherwise where would lazy manufacturers sell their sibilant crap?
Please continue & I will also continue - there's room for all of us!

 

[Phelonious Ponk]

You could be right and I could just be so used to my sibilant crap that it sounds good to me, John. I could buy your tweaked Hiface and be amazed at the disappearance of that which I do not now notice. What was I waiting for? Oh yeah, substance.

I doubt I'd hear anything, though. I think I have already accomplished what your modified hiface does through other means.

Tim

 

[jkeny]

You could be right and I could just be so used to my sibilant crap that it sounds good to me, John. I could buy your tweaked Hiface and be amazed at the disappearance of that which I do not now notice. What was I waiting for? Oh yeah, substance.

I doubt I'd hear anything, though. I think I have already accomplished what your modified hiface does through other means.

Tim

Ah cool! Now you can contribute some substance. Tell us all, please!

 

[Phelonious Ponk]

Ah cool! Now you can contribute some substance. Tell us all, please!

I've told it many times. I send USB to a battery-powered converter that galvanically isolates, re-clocks, then sends optical to my active speaker system and coax to my headphone rig. Can't say that it really sounds any different than taking optical straight from the MacBook to the speaker rig, but I need the multiple outputs, so there it is. Can't say it sounds any different running on USB power either, but I popped for the battery power supply, so I use it. Belt with suspenders.

The substance I was looking for was some evidence of the audibility of these distortions we're talking about. Pardon my skepticism, I mean no offence, but I don't hear it. I put headphones on, and with the drivers just milimeters from my eardrums I hear tons of detail, but none of these noises. How can I not be skeptical?

Tim

 

[jkeny]

I've told it many times. I send USB to a battery-powered converter that galvanically isolates, re-clocks, then sends optical to my active speaker system and coax to my headphone rig. Can't say that it really sounds any different than taking optical straight from the MacBook to the speaker rig, but I need the multiple outputs, so there it is. Can't say it sounds any different running on USB power either, but I popped for the battery power supply, so I use it.

Ah, all is clear now. You are right, you won't hear any difference with one of my USB-SPDIF converters as your system is designed to add enough of it's own noise & jitter to mask any potential improvements. I'm not surprised that you don't hear any difference between this set-up & direct optical from the Mac - both are equally inadequate!

Also not surprising that you don't hear any difference between battery power & USB power but you opt for battery power anyway! Good logic! As I said the industry needs people like you!

Belt with suspenders.

A bit too much information - I don't want to know about your personal life

The substance I was looking for was some evidence of the audibility of these distortions we're talking about. Pardon my skepticism, I mean no offence, but I don't hear it. I put headphones on, and with the drivers just milimeters from my eardrums I hear tons of detail, but none of these noises. How can I not be skeptical?

Tim

Sure Tim, as I said I understand & all is now clear. Of course you don't hear any difference & you are skeptical - I would be too given your system !

 

[jkeny]

Tim, can I ask you a question as gently as possible?
Do you ever wonder why all your blind tests gave you a null result?

 

[NorthStar]

...Because he's sitting in a 'null' zone?

 

[Phelonious Ponk]

Tim, can I ask you a question as gently as possible?
Do you ever wonder why all your blind tests gave you a null result?

Sure, all of my blind tests didn't give me a null result, though all but a few gave me a dull result. Now can I ask you a gentle question? Without real knowledge of what I'm using, how did you conclude that my USB-SPDIF converter was so inferior to your USB-SPDIF converter? It is curious. I'm using something that is basically designed to do exactly what you say your product does. You don't know the brand or the model. You have no measurements, not even any specifications. And yet you conclude that it is grossly inferior to your own product. Quite a feat.

Tim

 

[jkeny]

Sure, all of my blind tests didn't give me a null result, though all but a few gave me a dull result. Now can I ask you a gentle question? Without real knowledge of what I'm using, how did you conclude that my USB-SPDIF converter was so inferior to your USB-SPDIF converter?

Tim

Two words, Tim, re-clocking & optical out!
Can I ask you what one's did give you positive results in your blind tests?

 

[Phelonious Ponk]

Two words, Tim, re-clocking & optical out!
Can I ask you what one's did give you positive results in your blind tests?

FWIW, it also outputs coax, BNC and AES/EBU. Coax is what goes to my headphone rig, which is where I can most easily detect differences between components and media. And does your unit not clock the signal outside of the computer? Regarding optical, I've corresponded with quite a few designers who are of the opinion that optical is in the implementation. Does it have marginally higher jitter? Sure. How you deal with it is what matters. Come on, fess up, John, you've just been waiting for a bit of info you could use to dismiss my POV. And you jumped way too soon. And no, you can't ask what I got positive results on. I'm not feeding you anymore ammunition, thanks.

Tim

 

[jkeny]

OK, Tim, I can understand you feeling defensive.