Is there more to Audio Measurements?

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scott wurcer

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2004-01-26 3:03 pm
Belmont MA
Synchronous FFT meaning DAC & ADC working off the same clock & the tones generated with correct crest factor & frequency intervals (I presume the free tools do this?)

Yes, but you need to do the work. It's the classic canned user friendly software aimed at a target audience vs. a full R&D tool. Much of the work in the scientific and academic community has been paid for by tax dollars and is free to the rest of us. Python with scipy and numpy add ons or Octave come to mind. Both will do just about any of this stuff.

EDIT - By synchronous here I mean the frequencies are exactly centered on FFT bins. DAC/ADC clock frequencies are also important and are preferably the same. I had a sound card (pretty well known one) that had a flawed 44,100 Hz clock and a 1kHz exact tone came out 1.006kHz (verified with an Aglient frequency standard) that no one ever noticed.
 
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1st a need has to be actualized and often that is means counting those who think we don’t need to — in this thread, to name names, BV and Evenharmonics stand out as examples.
I don't know which post of mine you are referring to. Quote please.

yet differences between DACs can be heard,
Your claim would be more credible if you cite examples of that done in the listener's own setting and in their own leisure (to avoid any kind of stress excuses) along with identity of DACs (model and brand).
 

mmerrill99

Member
2014-08-16 12:41 am
Yes, but you need to do the work. It's the classic canned user friendly software aimed at a target audience vs. a full R&D tool. Much of the work in the scientific and academic community has been paid for by tax dollars and is free to the rest of us. Python with scipy and numpy add ons or Octave come to mind. Both will do just about any of this stuff.

EDIT - By synchronous here I mean the frequencies are exactly centered on FFT bins. DAC/ADC clock frequencies are also important and are preferably the same. I had a sound card (pretty well known one) that had a flawed 44,100 Hz clock and a 1kHz exact tone came out 1.006kHz (verified with an Aglient frequency standard) that no one ever noticed.

Thanks!
 
Will measurements get better? Undoubtedly. Will measurements get perfect? I doubt it.

What measurements correlate more to what we hear and which ones doesn't?

Surely, the decision to make measurements, what measurements to make, is that not subjective in the first place? Decisions, decisions... sigh!

I can think back to what I think was the seventies and these arguments about measurements applied to amplifiers because on the surface speakers had so much more distortion (still do, how is that for non-progress) and hence Peter Walker would say that his Quad 303 amp and Quad II amps did not sound different (that was the 60's) into 'high' distortion speakers. That at least is a synopsis of what I remember re back then.

So I do think we have made progress since those days, who argues that amplifiers all sound the same now? Not to many - at least I hope that is the case.

Speakers produce many mechanically related distortions (not entirely perhaps) and amplifiers can produce 7th harmonic distortion - how much can you tolerate of one and not the other?

Anyway, that my two pennies worth. I am not anti-measurement (who is?), and I am not anti-listening either! :)

Joe
 
Tossing all of this aside, I'm 42 years old. I've attended way too many parties with loud techno music, and stood in front of way too many festival sound setups.

Last year I was on holiday in France with my 70-ish year old parents, and I commented on the loud noise the crickets made. My parents were baffled, they didn't hear anything - complete silence. Our hearing goes down as we age, nothing we can do about it.

So... All I'm wondering is - does all of this matter for a random 42 year old guy with ears that have probably been abused a bit too much? I'm probably hearing only 75% of what I'd hear when I was 17, but didn't have the money to buy quality gear.

I really don't think my old ears will hear the difference regarding expensive power cables, speaker cables having break-in time, or cable risers for my speaker cables.

How old are you guys? Have you recently had your ears tested to find out their upper Khz limit? I'm in it for the hobby, and because I made it a psychological thing to want to have the best. But I don't have the illusion that silver looking speaker cable will actually give me better high frequencies. I probably can't hear them anyway.

I buy expensive **** because it makes me feel better, and it may look better... Because I want "normal" people to go "woah!" When they see my setup.

But I still think a random 17 year old will hear a much different sound.
 
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Never did this and sorry to say I could never hear any difference in customers reference designs at all no matter how carefully we listened.

I thought that's what you did & said here?

"The multitone really separates the sheep from the goats. I'm using 30 1/3 octave tones at about 12db crest factor. Artifacts show up on even the best boards."​

And later
"I see, right now I was just using a Fostex FR2LE and doing a diff on the results (there are obvious differences). There is a problem in general that one needs a reference A/D that is as they say "blessed". We should set this up, it's amazing how much work it is to put this all together."​
 
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So I do think we have made progress since those days, who argues that amplifiers all sound the same now? Not to many - at least I hope that is the case.

Well, not me, simply because it is in general a blatantly false statement. A Wavac SH-833 $350,000 FWIW) amplifier with 10% distortions and +/-6dB frequency response (load dependent) in the audio band sounds clearly different from my NAD mid-fi integrated amplifier (<$50 as salvaged from a flea market). For better or worse that's a different story and, since I've never had the chance to compare them in a preference test, it is fair to say simply "I don't know which one sounds better".

But I would challenge anybody to correctly identify two modern solid state amplifiers with measured distortions <0.01% and a bandwidth >100KHz, in a double blind test with carefully matched levels. If that's saying that all amplifiers sound the same, then I'm all in, sorry.
 
But Mr. Marsh and others claim Quad speakers were (and still are) particularly low distortion speakers. Such confusion.

They even have measurements to prove it.

The thing to know about Peter Walker and QUAD is that he designed everything relying purely on measurements. No listening or 'voicing' using music during the design process at all, only test signals. The Huntingdon facility did not even have a listening room.
 

scott wurcer

Disabled Account
2004-01-26 3:03 pm
Belmont MA
I thought that's what you did & said here?

"The multitone really separates the sheep from the goats. I'm using 30 1/3 octave tones at about 12db crest factor. Artifacts show up on even the best boards."​

And later
"I see, right now I was just using a Fostex FR2LE and doing a diff on the results (there are obvious differences). There is a problem in general that one needs a reference A/D that is as they say "blessed". We should set this up, it's amazing how much work it is to put this all together."​

Did I ever say I could hear any difference? The recordings on the Fostex sounded wonderful as posted on the Linear Audio site. Those were exactly the reference designs I was talking about you could measure differences down in the noise floor but no one could hear them. You can always find a way to measure or create a difference that you can't hear try the Souza test. You are taking a mistaken read, those comments were purely about lab measurements, I'm the wrong person to talk to about listening.
 
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scott wurcer

Disabled Account
2004-01-26 3:03 pm
Belmont MA
As for listening I'm with Romy...

I do not need to hear the distinct string section in the Bruckner 9. I do not need the “clarity”. To me the correct “Bruckner Sound: is something that I call “accordion sound” what everything is melted together and act as one “pressure force”. Gabriel Garcia Marquez described the Bruckner’s sound as sounds coming from stones spinning in a washer machine. I think something like this was possible only in war-time recordings and then, the recording technologies become “too inappropriately good” to record Bruckner…

If you want to mine old posts to prove something (I don't know what) please include the ones about music. Pretty childish behavior I think.
 
But Mr. Marsh and others claim Quad speakers were (and still are) particularly low distortion speakers. Such confusion.

They even have measurements to prove it.

And... the point?

No confusion. Please note that I did not type high, but I typed 'high' for a reason. The context was relative and not comparing apples and oranges.

Joe
 

mmerrill99

Member
2014-08-16 12:41 am
Did I ever say I could hear any difference? The recordings on the Fostex sounded wonderful as posted on the Linear Audio site. Those were exactly the reference designs I was talking about you could measure differences down in the noise floor but no one could hear them. You can always find a way to measure or create a difference that you can't hear try the Souza test. You are taking a mistaken read, those comments were purely about lab measurements, I'm the wrong person to talk to about listening.

As for listening I'm with Romy...

If you want to mine old posts to prove something (I don't know what) please include the ones about music. Pretty childish behavior I think.

I wasn't asking you about listening - I was asking what characteristics led you to define a DAC module as a goat rather than a sheep - I was just interested what you found in the measured differences.


Oh well, never mind, I have found a site that is a trove of interesting measurements, including multitone, for DACs, headphone amplifiers & headphones - Reference Audio Analyzer - it's in Russian but google does a good job of translation.

There is also a forum thread about these multitone tests here

They seem to categorize the multitone measurements into several categories:
- flat, uniform distribution of IMD products which they claim is probably good subjectively, not emphasizing any sort of sibilance
[IMGDEAD]https://reference-audio-analyzer.pro/report/dac/luxury-precision/luxury-precision-l3-dsd/Luxury%20%20Precision_L3%20DSD_Center_3_No%20load_-_multy10_150_20-22k_log_multy_distortion.png[/IMGDEAD]


- rising IMD products towards HF giving this sibilance or lack of clarity at HF
[IMGDEAD]https://reference-audio-analyzer.pro/report/dac/fiio/fiio-x1/FiiO_X1_Center_3_No%20load_-_multy10_150_20-22k_log_multy_distortion.png[/IMGDEAD]


- other variations of distortion product plots
[IMGDEAD]https://reference-audio-analyzer.pro/report/dac/cetrance/cetrance-mini-m8/CEntrance_Mini-M8_Center_3_No%20load_-_multy10_150_20-22k_log_multy_distortion.png[/IMGDEAD]
http://reference-audio-analyzer.pro...-_multy10_150_20-22k_log_multy_distortion.png
 
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