SINAD Measurements

[signalpath]

Chart says "Distortion and Noise (SINAD) Higher Better". That means 120dB SINAD is BETTER than 20dB SINAD. There’s nowhere said that Higher SINAD is Better perceptual audio quality!

Read Amir's foundational claims. Moreover, the word "better" in this context is obviously qualitative. And for noise, alone, that would be scientifically accurate. But for THD+N, it is opinion.

Now, that opinion may be best on his own experience, and I have no reason to doubt his work. But in terms of audio science, and the broader peer-reviewed, settled science community, it is nothing more than opinion.

 

[vitalii427]

Dude, the last time I got offended on a chat room was before the Internet.

Yes, I see that you are expertly arguing for the sake of argument

 

[pozz]

@signalpath
"Higher Better" is just a guide. Like for output impedance: "Lower Better".

The pointer is 120dB for total transparency, 96dB for good performance (matching the now very old CD format). The actual buying decision should be based on price, performance in other areas and features.

If you understand the equal loudness contours, room noise and gain structures with respect to playback, there should be no issue here.

 

[Xulonn]

In the context of ASR's claims, the question is irrelevant.

You've made a quantitative statement.

ASR makes a qualitative statement. Lower THD (SINAD) is more transparent.

Do I need to continue?

Now you've confused me - I thought SINAD was harmonic distortion plus noise, but now you claim that SINAD doesn't include noise?

But back to the basics, if SINAD is analogous to fogging on a glass window, you claim that reducing the fogging won't make the window more transparent?

 

[signalpath]

I anxiously await the protagonist's evidence that he - or anyone else can hear noise and/or distortion at -120dB. Until such evidence is provided, Amir's claims stand.

You have it backwards. Amir is making the claim that ALL audio equipment under ALL circumstances meeting -120dB SINAD is "guaranteed transparent."

This claim is not supported by today's audio science. Not even close. We simply don't have the depth and breadth of ABX testing at-hand to rise to the level of proven science. The statement is opinion, without broad peer-reviewed evidence.

The person who presents opinions as "facts" is on the line to present the science, not the silly guy in the corner waving his hand. Otherwise, in the spirit of good science, that person should retract the statement. Especially when it is used as a pillar of an entire qualitative ecosystem, called "Audio Science Review"

 

[vitalii427]

Master Review Index | Master Chart Index | Lecture Compilation | Interview Library | Amir's Recommended List

Thanks, @pozz

The best example how anybody here can make his own charts/lists/etc based on Amir's work and share with others!
@signalpath, I will be glad to see yours truly scientifically correct chart of audio equipment.

 

[RichB]

120 dB or 20 bits is required to reproduce most of the dynamic range possible on a 24 bit recording that also reflect the capability of normal human hearing. Perhaps, noise a more important for transparency than distortion but why not buy products without either within your budget.
If budget is a problem, examine the S/N data and engage your brain.

In my listening sessions, I find audible difference in reconstruction filters.
This site measure these filters and from this users can determine 1) that there are choices, and b) that they are well implemented in terms of attenuation.

Product usability and subjective quality are not the focus of this site but the data presented is invaluable, much of it is available no where else.

- Rich

 

[signalpath]

why not buy products without either within your budget.

Because THD is not necessarily an indicator of perceived sonic performance. There is no peer-reviewed, scientific correlation between THD and perceptual quality (beyond a certain threshold). A higher-THD product may indeed perform far better than a lower THD product. There's no scientific correlation (beyond a certain threshold).

In my listening sessions, I find audible difference in reconstruction filters.

Absolutely. And which, IMO, is the only scientifically-based argument for sample rates over 48kHz.

Product usability and subjective quality are not the focus of this site but the data presented is invaluable, much of it is available no where else.

Yes, invaluable data here. I love this site, and Amir is an asset to the audio community. But he really needs to learn the difference between audio quality and THD specifications. For instance, in the Liberty DAC review today, he notes that the Liberty has slightly higher IM distortion than the Topping DAC.

That's fine.

But then he editorializes: "Not good to get beat by a $250 product"

Get beat? In what regard? Not good to get beat? Huh? Does the Topping sound better? More transparent? Better musicality and empirical purity to the source? Does a slightly lower IM number magically bestow special provenance on the topping, so that it "triumphs" (beats, prevails, conquers, etc.) over the Liberty?

We have no idea. The reviewer is simply editorializing his biases, i.e., "Lower IM is BETTER."

No.

That's not audio science.

In reality, nobody "got beat" -- the slight difference in IM says nothing qualitative about Liberty's performance. The reviewer is making a worthless, throw-away claim that does nobody any objective good. Comparing THD numbers in a psuedo-qualitative manner like this is folly. I would use a stronger word right now, but you get my angst.

Not science.

 

[MRC01]

... Because THD is not necessarily an indicator of perceived sonic performance. ... the slight difference in IM says nothing qualitative about Liberty's performance. ....

All else equal, lower THD and IM is better, even if they're already below audible thresholds. It means better performance (whether or not any given person can hear the difference). The only time lowering them becomes a problem is if it's done in a way that sacrifices some other aspect of performance.

If we're talking about the difference between performance: measured versus perceived, then it opens a whole different can of worms. Some will say that tube amps and vinyl have superior perceived performance even if their measured performance is worse.

 

[scott wurcer]

Shorted? Depends on the model (we have, I think, 12 models of micamps). Best case, around -133dB EIN, 0 ohm source. Better to test with typical microphone source impedance, which averages around 150 ohms (as low as 20, as high as 600).

Yes, transformers give free gain, and we in fact use Per Lundahl's MC phono transformers in our Library of Congress phono archiving system. They are remarkably pure, extended, and "three-dimensional."

I threw that last descriptor in there just to piss u off.

The Library of Congress is mostly interested in archiving old 78 LP's you must have to order some unusual MC cartridges. If you can mount an argument for pre-amp SNR and THD vs a 78 LP I really want to see it.

EDIT - Sorry I'm wrong on that there are plenty of wax cylinders and 16RPM acetates.

 

[signalpath]

All else equal, lower THD and IM is better, even if they're already below audible thresholds.

It is better only in a quantitative manner.

In a qualitative manner, the statement is undefined and without moorings.

That's the essence of this entire conversation -- those who think lower distortion numbers necessarily mean better audio quality.

Not science.

You know, this exact conversation has been going on since I was a teenager building audio gear in my garage. And still people are being duped by the "lower THD is better" imposture.

 

[scott wurcer]

That's the essence of this entire conversation -- those who think lower distortion numbers necessarily mean better audio quality.

Not science.

So how about some science, there are published guidelines for perceptual testing for subtle differences in audio. Care to participate? I have no idea who would finance this endeavor it is very involved.

 

[signalpath]

The Library of Congress is mostly interested in archiving old 78 LP's you must have to order some unusual MC cartridges. If you can mount an argument for pre-amp SNR and THD vs a 78 LP I really want to see it. EDIT - Sorry I'm wrong on that there are plenty of wax cylinders and 16RPM acetates.

The Library (Brad McCoy, et al) have 12 independent audio archiving rooms. Each room has a 24-bit console set-up with a $30,000 Spanish turntable and Prism ADCs and ATC-150 monitors. We're in the middle, the phono preamp. Our preamp has unlimited EQ settings for old 78 recording curves. If the desired curve is not built into the selection switches, the user can swap socketed Rs and Cs to tailor the exact desired curve.

Each room also has a large collection of styli (mostly old Shure) to chose from. Each record (they have over 3,000,000 in the archiving queue) is observed under a microscope. The technician selects the stylus that best matches the grove geometry of the record. IIRC, they archive to 24/96 BWF files.

But that raises another issue: backing up the backup. HDDs will retain data for only so long. Every now and then, the entire audio archive must be refreshed onto new media. It's kind of a mess. Vinyl may be low dynamic range, but it lasts virtually forever.

 

[scott wurcer]

The Library (Brad McCoy, et al) have 12 independent audio archiving rooms. Each room has a 24-bit console set-up with a $30,000 Spanish turntable and Prism ADCs and ATC-150 monitors. We're in the middle, the phono preamp. Our preamp has unlimited EQ settings for old 78 recording curves. If the desired curve is not built into the selection switches, the user can swap socketed Rs and Cs to tailor the exact desired curve.

They spend my tax dollars, yes, but you didn't answer my question, what argument can you mount for the noise or THD of the pre-amp to matter at all in this process.

 

[signalpath]

So how about some science, there are published guidelines for perceptual testing for subtle differences in audio. Care to participate? I have no idea who would finance this endeavor it is very involved.

I've been pushing for this. I would love to participate in ABX tests, and also home testing using that harmonic distortion generation app.

 

[signalpath]

They spend my tax dollars, yes, but you didn't answer my question, what argument can you mount for the noise or THD of the pre-amp to matter at all in this process.

I don't make that argument for the archiving world.

The phono preamp also happens to be popular in the audiophile world, where the argument can be made.

By the way, the Culpeper Library of Congress (audio archiving) was originally largely funded by a private donor: one of the H/P guys, I forget which. I think it was David Packard. It was the largest private real-dollar gift to the U.S. Legislative branch in U.S. history. So not all of your tax money went to audio archiving. Oh, there's another story I learned when I visited the facility. It can't be shared on-line, so remind me to tell you when/if we ever meet up.

 

[March Audio]

In the context of ASR's claims, the question is irrelevant.

You've made a quantitative statement.

ASR makes a qualitative statement. Lower THD (SINAD) is more transparent.

Do I need to continue?

Which is a correct statement. Below a certain level you can say for that metric it is transparent.

No you don't need to continue. Arguing black is white, or making strawmen is quite tedious.

 

[scott wurcer]

The phono preamp also happens to be popular in the audiophile world, where the argument can be made.

Not really but no point in discussing it. LP's are rarely better than 0.5% or so THD and the surface noise is more than even a pretty good pre-amp.

 

[March Audio]

Read Amir's foundational claims. Moreover, the word "better" in this context is obviously qualitative. And for noise, alone, that would be scientifically accurate. But for THD+N, it is opinion.

Now, that opinion may be best on his own experience, and I have no reason to doubt his work. But in terms of audio science, and the broader peer-reviewed, settled science community, it is nothing more than opinion.

No. Your argument here is obtuse in the extreme. It's become farcical.

 

[March Audio]

I've been pushing for this. I would love to participate in ABX tests, and also home testing using that harmonic distortion generation app.

@amirm does ASR have the funds for you to visit @signalpath, or for him to visit you and perform the test I suggested earlier? To see if he really can consistently identify two similarly performing op amps under controlled conditions as he claimed?