Low-phase noice clock for ethernet, 25Mhz

[syn08]

You didn't read the paper did you.

No, and I do not intend to; life is to short to spend on reading every piece of junk one may encounter (not to mention paying for).

$33 thrown in the sewer (or making a stupid use of an AES Library subscription, there are good things in there) for that paper. Knowing what it takes to push a poster at an AES conference, any engineer/scientist that values his title would be much more suspicious, but I guess you consider anything that fits your agenda of pushing audiophoolish nonsense is worth distributing on a public forum with a certain audience.

 

[gerhard]

> What about -dB? Did you forget about that?

> I don't know exactly what Rob Watts said or meant, but I know
> he talked about really faint and subtle audio changes, so I assume
> he meant a range of about -200dB to 100dB


Can't you see that you make a complete fool out of you?
For everybody to see?

 

[jaddie]

But that's the whole point, isn't it? There isn't a uniform jitter threshold for all listeners, as is true for most other audio error parameters as well.

I dispute that statement on the grounds that there's insufficient evidence.

Yes, at some level, conversion jitter will be inaudible for essentially all listeners.

Agreed, but there is no single type of jitter spectrum, so there can be no fixed threshold...a "number" as a reference of audibility. Think THD. It's just no single figure of audible threshold, it's the spectrum, harmonic content, type of generation, plus masking. Same thing with jitter.

That level, however, is currently in dispute is all.

Not in dispute, just not known for the above reasons and lack of research.

Your assertion that jitter is not relevant below levels that provoke hard bit-errors doesn't make that assertion universally true. It's your opinion. Fine.

That was not my assertion. If it was read that way I apologize.

As you yourself had pointed out, jitter audibility isn't simply a matter of it's amplitude, for jitter is a complex structure. Which leads me to wonder why you now seem to be countering your earlier statement?

I'm not, but as I've said before, we are NOT discussing the audibility of jitter here. We're discussing the audible impact of network data transmission, of which jitter may or may not be one component. My assertion regarding that topic is that by nature, network data transmission absolutely requires buffering and re-clocking, which other means of data transmission do not (AES, USB, Toslink), though clearly they could benefit from it.

First, my initial post was in response to your prior statement, repeated here:

"If you don't change the bits, you don't change the resulting sound. I agree that if the data arrives at the DAC bit-perfect, the it will be bit perfect without the tweaks. But, if it's arriving bit-perfect, then what are we trying to change?".

Correct. Data integrity is what network data transmission is designed for.

You are clearly suggesting that jitter is a non-issue unless it provokes bit-errors.

That's true, but also, by nature, network data transmission absolutely requires buffering and re-clocking. That basic requirement works in strong opposition to classic data transmission induced jitter. So, on the network level, jitter would have to be above a threshold that resulted in data corruption to be an issue. This is NOT true in other forms of data transmission, however.

Bringing up other error parmenters, such as noise, is an attempted evasion.

I didn't bring up noise, other than to say it is always present and never zero either. No evasion by me was meant at any time.

One kind of error being lower in power than some other kind of error doesn't automatically render the smaller error inaudible. Surely, you know that.

Of course, but somewhat tangential to the discussion.

I have already made quite clear that I've been referring to conversion jitter.

I've already made it clear that in the context of the thread, that is off topic.

As I've also previously made quite clear, as long as bits remain in the digital domain, jitter does not matter, so long as it isn't severe enough to provoke bit-errors over a given data transmission link. That is basic. It DOES matter at levels below that which would cause transmission bit-errors in systems where domain conversion (ADC/DAC) is taking place. Digital audio is, of course, such a system.

I completely agree. However, we should separate the to. Data presented to a DAC after network transmission must by definition be buffered, reassembled, and reclocked. That's the very nature of jitter reduction and elimination.

The key question is, how do you know whether a given instrumented jitter measurement is low enough for the ear? Is this merely an judgment of how 'nice' a jitter plot appears to the eyes on a display screen? Is that any less an arbitrary yardstick than is the ear? More reapeatable yes, less arbitrary, I don't think so.

I think I've been quite clear that determining a jitter audibility threshold is, for several reasons, impossible at this time. What can be determined is its presence and relative degree.

Yes, measuring jitter is trivial with the proper equipment.

A good stable FFT and low jitter test signal is all that is needed. I've done it with a relatively low cost sound card, and REW.

Eliminating it is impossible. Reducing it to inaudibility, however, is the design issue.

Agreed.

Audibility is in the ear of a given listener.

Not agreed, lack of evidence that jitter audibility is individualized.

You may feel that your ears don't perceive jitter's affects, that's fine.

Please do not put words in my mouth or make assumptions. I've never said anything of the kind. But I have observed and measured jitter. Anyone else?

Others, however, obviously feel they do perceive it's affect. I didn't read anyone declaring that you do indeed hear the affect of jitter when you feel that you don't. Why then do you declare that they do not hear it when they feel that they do?

What they declare is fine, but how they make their observations can either validate or invalidate their observations. We've had the subjective/biased/sighted discussion already. Good science will not let the absence of good scientific practice go ignored. There are definitely ways and means to use human hearing as the final arbiter of the question of a phenomenon's audibility. A single individual conduction a sighted test with expectation bias in full effect is not one of them.

After decades of research using various means of collecting statistical data based on subjective observation, I can assure you, it does make a difference to do it right, and it does invalidate (basically pollute your data with noise) to do it wrong.

I'm really tired of arguing with the "I know what I hear" guys. In actual research, humility is key. You don't know everything, you don't know what you don't know, so you try to find out more. The above group is stuck at the first step, and won't go any farther. Thus, they are not actually accomplishing their goals either.

 

[MagnusHH]

Yea, but we are not talking about sound pressure here, 300 dB would probably split the earth in pieces. Surely you engineering guys knows that dynamic range is often used for something else, but if not check section Audio: Dynamic range - Wikipedia

 

[MagnusHH]

Can't you see that you make a complete fool out of you?
For everybody to see?

Check my last reply, whos the fool now?

Stop trolling please!

 

[Evenharmonics]

Very few if any people hear as much blind as they do sighted, but then again most blind testing of audibility is probably done incorrectly especially if ABX protocol is used.

You are probably just making that up.

 

[MagnusHH]

c) use one of these: 35SEPF22M (22uF/35V). Solder this cap to OUT+ and OUT- outlets on reg board. Keep the legs as short as possible.

Ordering some of those, so anywhere else I can put them? For example, I use batteries to power my DAC and streamer, would they benefit from caps(I would guess no but I'm a novice about these things)?

 

[Markw4]

...I guess you consider anything that fits your agenda ...

You guess wrong, as usual.

The argument about what people can or can't hear has been going on for decades in audio forums. In the end your side will lose. No other outcome is possible since science will prevail over time.

 

[Markw4]

You are probably just making that up.

YouTube

 

[syn08]

The argument about what people can or can't hear has been going on for decades in audio forums. In the end your side will lose. No other outcome is possible since science will prevail over time.

Yes, and the marmot will keep wrapping chocolates YouTube

 

[jaddie]

Yea, but we are not talking about sound pressure here, 300 dB would probably split the earth in pieces. Surely you engineering guys knows that dynamic range is often used for something else, but if not check section Audio: Dynamic range - Wikipedia

Interesting, if silly, digression.

Ultimately, we are always talking about SPL. Our reproduced dynamic range must fit within certain limits, room noise at the bottom (typically 20-30dB SPL and threshold of hearing below that doesn't matter), hearing damage at the top. You cannot reproduce the full dynamic range of a true 24 bit system, for example, without damaging your hearing permanently, even for a short exposure. 20dB (room noise) + 144dB = 164dB SPL, or 24 dB over the threshold of pain. Fortunately there are no true 24 bit recordings from a DR standpoint.

Maximum undistorted SPL in air is 191dB SPL, assuming a symmetrical undistorted waveform. At that point the rarifaction part of the cycle goes to a vacuum. You can go higher in SPL, but air will no longer be linear.

300dB would damage many things, but wouldn't split the earth. At least it hasn't so far, when that level has occurred on earth.

 

[TNT]

Please, someone have the mercy to lock this thread. It is the first time of all my years here that I feel this. I guess the day had to come. Worst is that it's run by a fellow Stockholmer...

I publicly hereby beg for forgiveness for this charade. I'm sincerely sorry.

//

 

[jaddie]

You understand to down to a certain level, but you omit where it can get more complicated.

For the frequency domain, your claim applies only if waveform changes are stationary over the time of the FFT and the time of any averaging that may be done to attenuate displayed noise. IME, not all audible effects of RFI/EMI on dacs are sufficiently stationary to measure with a soundcard and or scope.

No, but they're also very easy to differentiate from the desired signal. Many ways to do it.

There is also hysteresis distortion which can be hard to measure at low levels and which is nonstationary, but its still audible according to Purifi: This Thing We Have About Hysteresis Distortion - PURIFI ...just a few examples of where it can get more complicated.
The foregoing is for (mostly) nonlinear distortion.

It's not hard to see that those principles do not apply in the context of the discussion.

Linear distortion is harder to measure at very low levels, particularly if it is somewhat dynamic (which makes it weakly nonstationary). Take the case of audible effects due to interconnection cables, as one example: AES E-Library >> Physical characteristics of analog audio cables and their effect on sound quality

Interesting, but off topic again.

If one only thinks of examples such as where REW and a sound card are easily applied, one may conclude that's all there is.

I have not concluded that's all there is. But it is a very good starting point that some here either refuse to take advantage of, or refuse to see the value of.

You can do something basic, and get some good information, or you can find an objection to everything, finding something wrong with every test method, and invalidating it because it's incomplete, and thus do nothing, and get no useful information.

Your choice.

 

[MagnusHH]

I publicly hereby beg for forgiveness for this charade. I'm sincerely sorry.

If you weren't so unpleasant and flaming so much, I would invite you so you could hear yourself. Its not hard to hear difference between old switch and this modded NIC, at least not in my HiFi system.

 

[Ken Newton]

...I'm really tired of arguing...

One of the few things we agree on. So, I'll leave it at that.

 

[Pano]

There comes a time when a thread has run its course and serves no further purpose. This thread is closed until further notice. Please see the RULES section.