Measurements of Switches - Is this worthy of a proper response in the form of a YouTube Video of Amir for example???

[sam_adams]

He measure phase noise on the DAC clock!
And yes: jitter in the time domain is phase noise in the frequency domain

How many times has @amirm measured jitter in the DAC reviews he has done and demonstrated by the measurements—not concluded—that the jitter is inaudible?

 

[Hayabusa]

Hans Beekhuyzen!

?? I thought it was interesting to see they actually measured a relationship between network traffic and DAC clock jitter.
No matter how untrustworthy you think of Hans, that measurement is there.

 

[Hayabusa]

How many times has @amirm measured jitter in the DAC reviews he has done and demonstrated by the measurements—not concluded—that the jitter is inaudible?

Indeed, so that's what missing in the story, he should show in a blind test that he can hear these small jitter differences.

 

[amirm]

It is because they claim they have found something much much much better than Amir’s Audio Precision APx555 (something in the 300 MHz range! ).

The scope he uses is cheaper and is essentially useless for measuring audio fidelity. They need a high-frequency scope because they are trying to measure jitter at the clock input to the DAC. That clock runs in 10s of MHz so you need a high frequency tool to measure it. We don't listen to that clock though. We listen to the analog output of the DAC. There, my analyzer fully covers the audio band all the way up to 1 MHz. Importantly, it does it using 24-bit ADCs that provide far lower noise to detect very low levels of jitter and noise.

They do have an audio analyzer and it is by Prism Sound (dScope). It is a good device but has lower performance than my analyzer so not useful for measuring state of the art audio products.

 

[amirm]

FYI, I created a separate thread on their testing here: https://www.audiosciencereview.com/...show-benefit-of-audio-network-switches.48256/

 

[sam_adams]

?? I thought it was interesting to see they actually measured a relationship between network traffic and DAC clock jitter.
No matter how untrustworthy you think of Hans, that measurement is there.

Nothing that Hans Beekhuyzen does or says is interesting. Remember, Grandfather say, "Don't believe anything you hear and only believe half of what you read."

 

[Stokdoof]

Is there a market for a streaming service that can stream music data from their data storage to my home only using audiophile network equipment ?

 

[sam_adams]

FYI, I created a separate thread on their testing here: https://www.audiosciencereview.com/...show-benefit-of-audio-network-switches.48256/

Best part of that discussion is that someone dragged the woefully unprepared Paul into the spotlight.

 

[Rja4000]

they made the comparison between live (Piano; Chamber Quartet) and the recording of a file taken 5 minutes before. Then they started the music again and the musicians faded sometimes during the piece out and they faded the recording in.

The Speaker they used was the Cabasse Albatros V.

Cabasse was very familiar of this exercise.
I personally never attended such a show, but I've read it could be very impressive.

My main speakers were a pair of Cabasse columns, for 20 years, from 1994 to 2014.

I like their dynamic capabilities and "similar to live" performance.
They have quite a few flaws, for sure, and modern speakers are better on several aspects.
But the punch and capacity to convey realistic dynamic is still very competitive, even by today's standards.
So I still use and enjoy them.

 

[HarmonicTHD]

and:

How a network switch affects audio playback - An extreme deep dive!

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alpha-audio.net

What I really like about the alpha-audio guys is that they sometimes do also comparisons between live music (piano and singer) and the recording of that music at the exact same place with nice studio speakers.

That reminds me of something I had heared in 1984 or 1985 at an audio show by „Deutsches HiFi Institut“: they made the comparison between live (Piano; Chamber Quartet) and the recording of a file taken 5 minutes before. Then they started the music again and the musicians faded sometimes during the piece out and they faded the recording in. I was 19 or 20 years old. After two or three switches between live and the recording I was not shure what I heared. I remember that one time I could have swear that I hear the recording of Wolf Harden, the pianist. But damn: it was just He, in Person, playing live!!!
One of the most remarkable audio experiences in my live!
The Speaker they used was the Cabasse Albatros V.
Two hours later they tried the same with Bigband-music and large JBL Everest or K2 or so speakers. But they failed. The Bigband had simply to much power, was to loud, when it plays in reality. Even the large Horn Speakers could not give the full dynamic that was needed.

But what I want to know is: Is this measuring of Alpha audio just rubbish or is it COMPLETE rubbish?

Short answer: complete utter senseless rubbish.

The why has been well explained by others already.

 

[Keith_W]

Phew. I watched that video and nothing made sense to me. I am glad that this thread cleared it up.

 

[totti1965]

The scope he uses is cheaper and is essentially useless for measuring audio fidelity. They need a high-frequency scope because they are trying to measure jitter at the clock input to the DAC. That clock runs in 10s of MHz so you need a high frequency tool to measure it. We don't listen to that clock though. We listen to the analog output of the DAC. There, my analyzer fully covers the audio band all the way up to 1 MHz. Importantly, it does it using 24-bit ADCs that provide far lower noise to detect very low levels of jitter and noise.

They do have an audio analyzer and it is by Prism Sound (dScope). It is a good device but has lower performance than my analyzer so not useful for measuring state of the art audio products.

The Alpha-Audio statement of their Test-Equipment:


„So forget data… it’s not there.

The measurement setup​

For this study, several more members were added to the measurement family. First of all, the Wavecrest SIA 3000. This is a Signal Integrity Analyzer that can literally measure jitter down to the femtoseconds. The internal resolution is 200fs (femtoseconds) and the internal reference clock has less than 1ps of jitter. Our calibrations on the machine itself confirm this (it had to recalibrate itself after traveling from South Korea). This is really very impressive for a machine from 2002. And also for a machine released in this decade. With reason, these machines were practically priceless at the time of release. It really is an extremely accurate – and sensitive! – device with which we can thus measure clock jitter with precision. And phase noise, low-frequency modulations, etc. We don’t have all the licenses available, unfortunately, but enough for what we do. And additional licenses… are somewhat pricey… understatement.

In addition, we purchased a new Rohde & Schwarz probe. This is to achieve a decent bandwidth for the measurements; the R&S probe has a bandwidth of dc to 300 MHz. Enough for this project.

And finally, we purchased an impedance buffer amp to convert from 1 MOhm to 50 Ohm to connect to the Wavecrest with the proper impedance. This machine has an input impedance of 50 Ohms. We chose a model from Matthews Engineering because of the price/quality (dc – 400 MHz and very quiet) and the fact that it works on batteries as well as usb-power. We ended up powering it via an adapter from USB to the lab power supply.“



I assume that this is all to test network related Jitter?

 

[Frank2]

FYI, I created a separate thread on their testing here: https://www.audiosciencereview.com/...show-benefit-of-audio-network-switches.48256/

@amirm In that thread you explain that 512 ps of jitter corresponds to the 16th bit of a pcm sample in terms of noise level.
Am I allowed to proceed as follows?
512 ps = bit 16
256 ps = bit 17
128 ps = bit 18
64 ps = bit 19
32 ps = bit 20
16 ps = bit 21
8 ps = bit 22
4 ps = bit 23
2 ps = bit 24
?
Or is that an oversimplification?

Because in that case, the jitter difference measured by Hans is irrelevant, since both measured values correpond to 20 bit resolution.
He measures 14.6 ps and 11.7 ps.

 

[Koeitje]

It is because they claim they have found something much much much better than Amir’s Audio Precision APx555 (something in the 300 MHz range! ).
I am solely hoping for a new Amir video! I am longing for that! Amir has to do something!

Anyone who thinks switches make a difference doesn't understand networking protocols.

 

[antcollinet]

Amir has to do something!

No, he really doesn't

If he made a video debuning every bit of bogus snake oil on the market, we'd never get anything actually useful out of ASR.

Let the snake oil merchants provide actual measurements proving somethign audible on the output of their DAC as a result of using these devices in a realistic setup - then it might be worth having a discussion.

We see in our measurements a direct relationship between low-frequency noise from the network port and phase noise on the clock.“

That does not equate to audbile impact. If that phase noise makes an audible impact at the dac, let them first show the measurements for that.

And if this video is the one I think it is - they are sticking a bloody great probe on the clock signal. That alone will inject noise into (and or capacitively load) the clock signal in ways that certainly far outweigh anything coming in from the network.

 

[Scytales]

That reminds me of something I had heared in 1984 or 1985 at an audio show by „Deutsches HiFi Institut“: they made the comparison between live (Piano; Chamber Quartet) and the recording of a file taken 5 minutes before. Then they started the music again and the musicians faded sometimes during the piece out and they faded the recording in. I was 19 or 20 years old. After two or three switches between live and the recording I was not shure what I heared. I remember that one time I could have swear that I hear the recording of Wolf Harden, the pianist. But damn: it was just He, in Person, playing live!!!
One of the most remarkable audio experiences in my live!
The Speaker they used was the Cabasse Albatros V.
Two hours later they tried the same with Bigband-music and large JBL Everest or K2 or so speakers. But they failed. The Bigband had simply to much power, was to loud, when it plays in reality. Even the large Horn Speakers could not give the full dynamic that was needed.

Fascinating !

Thank you very much for this testimony.

 

[fpitas]

Is there a market for a streaming service that can stream music data from their data storage to my home only using audiophile network equipment ?

Yes, they'll only string audiophile grade cables. Honest

 

[CapMan]

what is the 2ps of jitter they quote as an improvement in the context of something measurable in frequency response that we can agree does change the sound - eg moving ones head by a micro meter whist listening, or a fly farting in the listening room ? !!

 

[antcollinet]

Is there a market for a streaming service that can stream music data from their data storage to my home only using audiophile network equipment ?

No - but if there were, how would it work.


How would it get from the streamers datacenter to your house without going through dozens of bits of kit that are not audiophile?

 

[Rednaxela]

It starts with an audiophile datacenter.