Two unresolved issues

[Stereoeditor]

And why do you think a null test is not proof?

I haven't made any comment on null tests in this thread, Ethan.

But that's the subject of this thread. That, and what specific physical properties of sound digital recording cannot capture.

So what? I commented on a posting by Bruce Brown in which he gave some relevant links and I then asked you about the measurement equipment you use. Both on Hydrogen Audio and on this forum, you mention measurements as supporting your arguments, so I was interested in what measurement equipment you actually use. I made no comment of the efficacy or lack thereof of null testing, so your question in message #171 - "And why do you think a null test is not proof?" - is yet another example of you putting words in my mouth.

But these are both software solutions. Their performance will therefore depend on the hardware with which they are used....

Of course, but they're still highly useful tools. And they can easily settle the question of, for example, at what level are artifacts no longer audible? If I could afford an AP analyzer, believe me I'd own one

So if you don't use something like an Audio Precision to measure amplifiers and digital products, how can you be so sure that your measurements and null tests are good enough to characterize the performance of the devices under test?

What A/D converters do you use, what is their resolution/noisefloor performance, and what calibration have you performed of that hardware?

[No response from Mr. Winer]

I'll ask again, Ethan, as perhaps you missed this question. What A/D converters do you use, what is their resolution/noisefloor performance, and what calibration have you performed of that hardware?

John Atkinson
Editor, Stereophile

 

[Bruce B]

I'll ask again, Ethan, as perhaps you missed this question. What A/D converters do you use, what is their resolution/noisefloor performance, and what calibration have you performed of that hardware?

John Atkinson
Editor, Stereophile

As well as microphones and mic preamps. Surely someone who does room acoustics and analysis must have top notch equipment for your business.. or is it just "good enough"?

I still can't get over the fact you can't read a spectrogram...

Wiki definition for you

 

[amirm]

John, I think we know the answer to the question you are asking Ethan. Namely, he doesn't believe after certain point, increased fidelity matters. For that reason, for both personal and professional equipment, he stops way lower than the absolute highest performance gear. I realize there is some satisfaction in getting him to list said equipment . But we know that already so the real value is not there.

Ethan, I hope you take John's point to heart and that of others here who really want to achieve the highest performance. And this is for the sake of discussion, is regardless of price. So while the notion of "what is the value of extra performance" is a good topic to be had elsewhere, it has less of place in a forum called "what is best." John has a point that unless one has experience with the best whether it is test and measurement and actual gear, maybe one hasn't discovered all there is to know. I know that applies to me.

So let's move past the person and discuss technical matters. Assuming there is any .

 

[JackD201]

Consensus is not how margin for error works, Lee, but that's a moot point. We would never get a margin for error agreed upon unless everyone agreed with the results.

That wasn't Lee Tim, that was me. We've got things in reverse I think. When doing a test on a target population, the sample size determines the level of confidence right? Even at this very early stage the level of confidence has to be agreed upon whatever the results might be. Same goes for the analysis of the results depending on the stringency of the trial. Redbook got the green light because theory and testing at the time showed 16/44.1 was viable, whether or not they knew more bit-depth and higher sampling would be better in 1980 is still a bit of a mystery. 16/44.1, 24/48, 24/88.2, 24/96 are all "waypoints". We need "waypoints" otherwise nobody would be doing anything in common. That's why all formats must be ratified by the IEC. Again I'm oversimplifying but I hope you see what I mean.

My attraction to the goings on in files for download is that the files are no longer chained to a physical medium and neither is the processing chained to specific chip-sets. I don't know ultimately where resolution will top off but all of the aforementioned suggests getting there will be exponentially quicker and have a chance at market success. Quality didn't kill DVD-A and SACD, failure to penetrate the market did.

 

[Lee]

John, I think we know the answer to the question you are asking Ethan. Namely, he doesn't believe after certain point, increased fidelity matters. For that reason, for both personal and professional equipment, he stops way lower than the absolute highest performance gear. I realize there is some satisfaction in getting him to list said equipment . But we know that already so the real value is not there.

Ethan, I hope you take John's point to heart and that of others here who really want to achieve the highest performance. And this is for the sake of discussion, is regardless of price. So while the notion of "what is the value of extra performance" is a good topic to be had elsewhere, it has less of place in a forum called "what is best." John has a point that unless one has experience with the best whether it is test and measurement and actual gear, maybe one hasn't discovered all there is to know. I know that applies to me.

So let's move past the person and discuss technical matters. Assuming there is any .

Well said Amir.

 

[Lee]

I'd love to see some proof of that. Jitter manifests as sidebands, which is basically noise that's typically 100+ dB below the music. There are so many other reasons people might believe they hear a change that doesn't exist, I'll go with Occam until shown evidence to the contrary.

Are you really disputing Nyquist? Some circuit designs may come up short in their implementation, but you'll have a very difficult time proving Nyquist (and Shannon and Fourier) wrong!

--Ethan

Ethan, I think the historical record on increasing jitter awareness in transports is a matter of public record. There are posted Harley articles on the Stereophile website.

As for Nyquist, I think theory is fine for what it is but in practice there are issues in implementation. I've been able to play with all kinds of hirez and 16/44 recordings and there is not a small difference between the two although the gap has narrowed somewhat as CD playback has matured.

 

[Bruce B]

Who can tell me what this is and what it sounds like?

 

[Bruce B]

What does THIS SACD sound like? Would anyone like it?

 

[JackD201]

All I see is that it is an average of something over a 6.615 period. I only know the duration because I cheated and looked below! It could've been an hour and I still wouldn't know by looking at the graphs alone.

No I don't know what it is and I can't say what it sounds like.

Anybody else?

 

[fas42]

Who can tell me what this is and what it sounds like?

The signature rumble of a silent track on a test LP, on a particular TT?

The SACD 19kHz tone would be inaudible at nearly 80dB down, unless you were a young kid with your ear jammed against the tweeter

Frank

 

[Bruce B]

The signature rumble of a silent track on a test LP, on a particular TT?

Frank

Whew!! Close...!! It's actually the "sound" of the ambience between tracks on a Proprius disc recording of the Stockholm Concert Hall Organ.

Good guess....

and the second graph is of the music.

 

[RBFC]

I was thinking of the sound of the subway beneath the concert hall or something similar for #1.

I've said for years that the dimensions of a space are best described by their fundamental resonances in the extreme deep bass.

Lee

 

[Bruce B]

I was thinking of the sound of the subway beneath the concert hall or something similar for #1.

I've said for years that the dimensions of a space are best described by their fundamental resonances in the extreme deep bass.

Lee

Yeah... I was checking these discs for hi-rez content and this one just struck me as odd.

 

[Bruce B]

I have the Hi-Fi News & Records Review Test Disc II. Starting on track26 are calibrated 1 Khz level, at 0db, and by track 35 down by 60db, and 70 db at track 36, 80db at track 37.

So what?

Well, play track 26 at as high a volume level you think you normally stand when listening, and then jump down to track say 33 and give a listen, and keep going down.

Why?
Tom

I just tried this. If I turn eveyrthing off in the studio, I can hear down to -90dB but no lower.

If anyone wants to try it... I've made some 1kHz test tones available on my server.


1kHz Test tones

 

[Ron Party]

Hi Bruce. Do you think your ability to hear -90dB is unique to your studio? I ask because your studio is as you've previously described a room within a room and has a lot of traps and other room treatment such that, I suspect, the ambient noise level in your room is much lower than many of us have in our own.

 

[Mark (Basspig) Weiss]

I can attest to differential mode amplifiers.. I run the amps to my mids and highs in bridged mode, which further cancels noise and distortion products, with a side benefit of being able to swing 340 volts peak to peak across an 8? resistive dummy load (for performance evaluation purposes). I did a lot of work over the years to increase the dynamic range of the system. The caveate to being able to play loud is having idling hum and noise that's loud enough to disturb the neighbors! Over the years, I worked out solutions to that, to the point where the system is inaudible at idle, except for cooling fans in the amps/racks. The differential mode is very clean and has seemingly limitless dynamic range. Everything is balanced througout, except the input sources. Maybe Oppo's BDP-95, with it's balanced outputs, may be a solution for my Ultimate Fireworks Blu-ray disc.

 

[Bruce B]

Hi Bruce. Do you think your ability to hear -90dB is unique to your studio? I ask because your studio is as you've previously described a room within a room and has a lot of traps and other room treatment such that, I suspect, the ambient noise level in your room is much lower than many of us have in our own.

I'm sure it has a lot to do with the room. I wouldn't be able to hear it if I were in my living room, that's for sure.

 

[amirm]

I like to caution against reading too much into whether you hear a low-magnitude tone or not and translating that into whether distortion products are audible.

Let's look at the spectrum of a sample piece of music I downloaded from our other trials here:

As you can see, while 1Khz to 2 KHz components are near 0db, for the bulk of the high frequencies, the level is a whopping -70 db down! Intuitively then, based on the listening tests of tones, one would think that would be very faint. Yet, if you listen to that music, you have no trouble hearing higher frequencies than just 1 or 2 KHz.

I tend to think that what we hear is the total energy in the higher frequencies. If you have a system that distorts, and sprays higher harmonics for every ton in your music into higher frequencies, it is liable to collectively increase the energy such that the music can sound "brighter" and edgier.

Now, I don't offer the above as proof . But having heard the effect countless time, that is the conclusion I have arrived at as to why we are able to hear harmonic distortion which at face value, seems to be small numbers.

 

[Robh3606]

But having heard the effect countless time, that is the conclusion I have arrived at as to why we are able to hear harmonic distortion which at face value, seems to be small numbers.

Hello Amir

Have you ever read these?? A contrarian point of view on the state of existing THD measurements corelated to what we actualy hear. An interesting read.

Rob

http://gedlee.com/distortion_perception.htm

 

[Bruce B]

I like to caution against reading too much into whether you hear a low-magnitude tone or not and translating that into whether distortion products are audible.

Let's look at the spectrum of a sample piece of music I downloaded from our other trials here:As you can see, while 1Khz to 2 KHz components are near 0db, for the bulk of the high frequencies, the level is a whopping -70 db down! Intuitively then, based on the listening tests of tones, one would think that would be very faint. Yet, if you listen to that music, you have no trouble hearing higher frequencies than just 1 or 2 KHz.
.

What about the spectrum in post #213? There is 18kHz energy 50dB louder than any of the surrounding frequencies. According to you, this should stand out like a sore thumb... if anyone could hear it!!