Master Thread: Are Measurements Everything or Nothing?

[voodooless]

If all you can do is claim I am wrong, then you are not helping the further of objective testing.

No, I’m not making any claims, I ask you to back up yours. All you do is demand whatever measurements back up those claims. That is not how it works.

It’s like you claiming Leprechaun exists, and then asking us to disprove it.

So once more: you make the claim, you provide the evidence. This does not start out with measurements.

 

[audio2design]

And what about that? Total disappointment. Harsh, one-dimensionality, in short - bad. Worst then 1st or 2nd generation of Marantz/Philips CD players.

I'm sorry, but the specifications on paper are not crucial to me. To theorists for sure, but in practice they can only be a guide that can interest me in this product in the sense that I go to hear it in the best possible conditions.

30 years later people are still calling digital "harsh" and lifeless. Is it? No. The harshness is from their existing vinyle system having an actual warm frequency response with poorly matched cartridge / amp emphasizing bass, maybe rolling off highs and hence anything introduced that is flat comes across harsh. Then you have issues with the underlying CD mix not limited by the need to suppress dynamics stressing speakers more. Add in lack of euphonic harmonics perceived as "air or space" and some crosstalk to help center an image in a room that is an acoustic mess ... and the end result is the CD is called harsh, flat, etc. when the real issue is not the CD/digital at all.

30+ years of acclimatization, coupled with 30 years of speaker development and perhaps most critical 30 years of hearing loss and now digital is accepted by all but the most harsh former critics. There have been some advances in digital too of course.

 

[Spkrdctr]

Right.

So where are the 50? Where is the one?

In heaven? Sure not here on Earth.

 

[Deleted member 23982]

and the end result is the CD is called harsh, flat, etc. when the real issue is not the CD/digital at all.

i also noticed "digital" sq without ever listening to tubeamps/vinyls x) you are talking about a "whole" other group, "retro-listeners" i would call them


well i was googling a little, because i got curious how multitones are actually produced with just "one" sinewave, kinda interesting topic and it got me thinking
"noise"... how is it embedded in the sinewave we see/hear? or other phrase, how will actual noise influence the "main" sinewave? could it be that noise has some influence of the perception of the maintone, even at points where we cant set noise apart from the main signal? (and measurements just working fine)
curious what you think, this would actually explain a lot, even on a scientific way
it would also explain powercables/usb filters etc effects, because even a tiny bit noisereduction could make a difference
it would also explain why more "precise" speaker (studio monitors for example) show this way more obvious, because they are "so" precise that they also influenced more by it

also, the thing we cant measure is: the actual sound-sinewave in the air (like the actual sinewave "midair") we just can measure it through a mic again and i really think our ears/brain are to specific things way more sensitive then mics that essentially just measure "volumes" (because "altered" soundwaves could hit the mic and the mic is essetially generating a sinewave by its own and maybe "filtering" things that way?

 

[audio2design]

If noise pushes a signal above a threshold it could make a previously inaudible signal audible. That works in the lab. In music not so much.

 

[Digby]

This ^^^
Those who understand the scientific method (or methodology) trust the scientific method.
Those who do not understand the scientific method (or methodology) do not trust the scientific method.
Ergo: if you don't trust the scientific method, it's because you don't understand the scientific method.

It's not a matter of belief, opinion, or preference. It's a matter of understanding. Jim Taylor

Isn't that something of an oversimplification though, in that all science will start with some anecdotal insight, that then leads to a hypothesis, then experimentation and so on.

Every scientific fact starts its life as a baseless assertion, until proven to stand up to overwhelming experimentation designed to prove it false, at which point it becomes a fact; maybe only a temporary fact, as new information comes to light or new insights are made, that renders it unsustainable. Then it might not be a fact any more.

I don't think it is a case of trusting, or not, the scientific method, but whether the science is complete. There may well be a number of things an individual can notice anecdotally, that if tested may turn up to be scientifically factual.

Those who make claims about speakers sounding different, for instance, and that the measurements may not fully account for this difference, are not by necessity the same brand of people saying that different cables have different 'sounds'.

If the science isn't complete, then anecdotes/assertions in an area where there could be something as yet unknown are not without value (but yes, they may have more or less value depending on a number of factors).

 

[tvrgeek]

May I suggest trying less to impress with poorly at times used acronyms and short forms not to mention imprecise descriptions? I.e. cone breakup can excite already existing resonances in the audible band, and new resonances above the audible band that modulate with frequencies in the audible and inaudible band to create new audible frequencies.

I was answering a question with the facts as I learned them. I am not writing a book on how to design an amp. Self and Cordell already did that very well.

 

[audio2design]

I was answering a question with the facts as I learned them. I am not writing a book on how to design an amp. Self and Cordell already did that very well.

I will go out on a limb and say the person you responded to didn't understand even half the acronyms. I have designed electronics, amps, etc formally for decades and I was unsure of what acronyms you were using at times and some details because of that seemed wrong. Like I said it came across as bafflegab.

 

[tvrgeek]

When class D amps came out, I saw the specs and rushed to hear one. It was terrible. (B&O) I heard several others. ( Rotel, Peach) All terrible. Some years have passed and by both objective measurements and by subjective descriptions, or significantly the failure to provide a description, it could be they have arrived. I am actually considering one where a year ago I would have told anyone to stuff it. I toss out to the measuring experience, from the last to the current generation, what objective measures have changed that might let us know the dividing line from "getting there" but still with a sonic signature, to "arrived" with no discernable signature. What can we put a number on, or can we?

This does risk the wrath of EGO PRESTIGE market if a $350 Topping can sound as nice as a $7000 prestige name amp of equivalent market? (Apartment relaxed listening, what most people actually need) Can a sub $2000 Purify or Hypex implementation sound as clean as Privetta? ( $2.2 million. yes dollars) I would wager a pint it does. What differs in the better module implementations that some may have no sonic signature, and some still do? Can we identify it and measure it? That should be the focus here. How to reach "measurement is everything" not trying to prove anyone who dares to listen to music is wrong.

 

[tvrgeek]

I will go out on a limb and say the person you responded to didn't understand even half the acronyms. I have designed electronics, amps, etc formally for decades and I was unsure of what acronyms you were using at times and some details because of that seemed wrong. Like I said it came across as bafflegab.

What would you like to know? I will gladly define them.

 

[audio2design]

What would you like to know? I will gladly define them.

I would say you should define them for the person you responded to who looking at their other posts had no clue what you were talking about. I guarantee there are many of us here who probably are more knowledgeable about amplifier design who were reading that and going WTF? When you add in missing words and wrong words (IE irreverent where irrelevant should have been used) , it becomes unreadable especially when you are using acronyms for which there are no real standards or discussing in the context where multiple things are in play (speakers and amps per se) and an acronym could have multiple meanings.

It is possible, and I have modeled it in Spice, that more complex IPS and VAS will have lower inherent distortion than DP compensation on a better amplifier can beat Miller on the simple one. I do not use a Darlington differential VAS. More can me done to my CM and CCS. There seems to be magical sweet spots for the ratio of IPS gain and feedback you can adjust by the LTP degen resistors.

I am going to save this in case I ever teach a course again. This tends towards the baffle them with BS category especially with the miswording and grammar errors that destroy readability.

 

[Geert]

i also noticed "digital" sq without ever listening to tubeamps/vinyls x) you are talking about a "whole" other group, "retro-listeners" i would call them


well i was googling a little, because i got curious how multitones are actually produced with just "one" sinewave, kinda interesting topic and it got me thinking
"noise"... how is it embedded in the sinewave we see/hear? or other phrase, how will actual noise influence the "main" sinewave? could it be that noise has some influence of the perception of the maintone, even at points where we cant set noise apart from the main signal? (and measurements just working fine)
curious what you think, this would actually explain a lot, even on a scientific way
it would also explain powercables/usb filters etc effects, because even a tiny bit noisereduction could make a difference
it would also explain why more "precise" speaker (studio monitors for example) show this way more obvious, because they are "so" precise that they also influenced more by it

also, the thing we cant measure is: the actual sound-sinewave in the air (like the actual sinewave "midair") we just can measure it through a mic again and i really think our ears/brain are to specific things way more sensitive then mics that essentially just measure "volumes" (because "altered" soundwaves could hit the mic and the mic is essetially generating a sinewave by its own and maybe "filtering" things that way?

You should write a science fiction book.

 

[Plcamp]

I will go out on a limb and say the person you responded to didn't understand even half the acronyms. I have designed electronics, amps, etc formally for decades and I was unsure of what acronyms you were using at times and some details because of that seemed wrong. Like I said it came across as bafflegab.

I easily understood half of them. But that doesn’t matter anyway.

It gave me something to think about that I had not (out of band noise). I appreciated it.

Just so you know.

Regarding J Crowe’s method, well I had not seen before a “many tone” IMD test that revealed a kind of noise floor like that, and I found it interesting that the noise floor tracks linearly with volume.

 

[tvrgeek]

I would say you should define them for the person you responded to who looking at their other posts had no clue what you were talking about. I guarantee there are many of here who probably more knowledgeable about amplifier design who were reading that and going WTF? When you add in missing words and wrong words (IE irreverent where irrelevant should have been used) , it becomes unreadable especially when you are using acronyms for which there are no real standards or discussing in the context where multiple things are in play (speakers and amps per se) and an acronym could have multiple meanings.




I am going to save this in case I ever teach a course again. This tends towards the baffle them with BS category especially with the miswording and grammar errors that destroy readability.

So, you can't say what you did not understand? Any you say you built amplifiers? I am confused at that.

What acronym would you like me to explain? If you built an amp, you would know what a CCS, CM, IPS, VAS, Miller, 2-pole, or DP compensation is. I hope you know what a LTP is and what degeneration means. If someone would like to learn, I have several times suggested the basic reading from Bob Cordell and Douglas Self. Marshall Leach was more the math fundamentals, where the others are practical implementations.

Or I could say " It's magic and I know best" Would that make you happy? I don't believe in magic and sure as hell don't know best.

I know there are differences that can be measured and some topology that influences them. I know how they influence and are influenced by the load. I know I can hear them at any level I can afford. I am not saying I can hear in all cases I can't afford.

4 or 8 Ohm resistive load is not the best at defining an amplifier performance, but unless it is a powered speaker so the load is defined you are kind of stuck. It is unrealistic to have a "typical " load as no load is typical. I have modeled approximations of different speakers in Spice and it can have an order of magnitude effect on the THD. I use that knowledge in my crossover designs. I commend Amirm for always doing 4 Ohms as well as 8. It is informative if you understand how class AB amplifiers work. Not perfect, but reasonable. I do not know enough about class D to know the interaction.

If there is a repeatable subjective difference, there is an objective difference. The question is how to identify and quantify it.

 

[Killingbeans]

"noise"... how is it embedded in the sinewave we see/hear? or other phrase, how will actual noise influence the "main" sinewave?

could it be that noise has some influence of the perception of the maintone, even at points where we cant set noise apart from the main signal? (and measurements just working fine)

What would make us unable to set the noise apart from the main signal?

also, the thing we cant measure is: the actual sound-sinewave in the air (like the actual sinewave "midair") we just can measure it through a mic again and i really think our ears/brain are to specific things way more sensitive then mics that essentially just measure "volumes" (because "altered" soundwaves could hit the mic and the mic is essetially generating a sinewave by its own and maybe "filtering" things that way?

A mic doesn't fabricate sine waves. It reacts to a value in air preasure at any given point in time. Those continuous values gives you the signal.

So no, it does measure the actual sound waves "midair", as you said youself. There's no interpretation, intelligence or magic involved.

A mic does however have a bandwidth and a frequency response. That's why you need a mic with an associated specific calibration file if you want to do 'flat' measurements.

EDIT: And yes, any mic also both distorts and makes noise, but that's the least of your worries when entering the realm of acoustics. Thankfully we can just look at the electrical source itself and forget about all that dirt

 

[Plcamp]

This is all pretty much known, hence why distortion measurements at multiple increasing SPLs swept by frequency but I like to see more IMD stimulus to induce Doppler.

One thing I am wondering. When a speaker is playing a multitone test signal, and exhibiting sideband IM distortion products, does the voice coil current also show the same IM products? To what degree are the IM products of a speaker driver even visible to the amp trying to control the driver…does the amp matter?

Hope this question makes sense.

 

[Deleted member 23982]

What would make us unable to set the noise apart from the main signal?

i meant by ear, so at a point where the noise is "inaudible" but essentially still "messing" with the main sinewave, which could become audible even if we dont hear the "noise" directly, this would atleast explain why "audiophiles" are always talking about "overall sound change"

A mic doesn't fabricate sine waves. It reacts to a value in air preasure at any given point in time. Those continuous values gives you the signal.

So no, it does measure the actual sound waves "midair", as you said youself. There's no interpretation, intelligence or magic involved.

no i know but no transducer or what its called is perfect, couldnt the "mass" of the mic membrane actually "filter" something out? so essentially smooth a noisy sinewave again?


also we thrief for "realistic" sound but speakers/headphones dont quite reach this state no matter what we do, isnt the "noisy" sinewave (electrical and by the actual speaker outputting soundwaves) essentially what sets it apart from "natural sounds" ? (beside distortion and other things but i guess you could call them "noise" too) i mean many talk about dacs outputing "perfect" sinewaves that are same to eachother (or does this just get explained with, "noise isnt audible anymore" ?)

if we are purely scientific speaking this is pretty much the only explanation that can explain "audiophiles" subjectiv expierences (yea sure, placebo is a option too....) IF we are at a point where everything is measurable
maybe everything important is measurable, we just dont aknowledge the influence by it eg "inaudible"

 

[audio2design]

I knew exactly what you meant tvrgeek as I speak DIYaudio, but it may surprise you that people who design amplifiers for money when the speak will say long term pair and current mirror and constant current source, not all the acronyms which are usually used by DiY trying to fit in. But then they are probably more likely to say emitter coupled pair or differential pair ...

 

[Jimbob54]

i meant by ear, so at a point where the noise is "inaudible" but essentially still "messing" with the main sinewave, which could become audible even if we dont hear the "noise" directly, this would atleast explain why "audiophiles" are always talking about "overall sound change"


no i know but no transducer or what its called is perfect, couldnt the "mass" of the mic membrane actually "filter" something out? so essentially smooth a noisy sinewave again?


also we thrief for "realistic" sound but speakers/headphones dont quite reach this state no matter what we do, isnt the "noisy" sinewave (electrical and by the actual speaker outputting soundwaves) essentially what sets it apart from "natural sounds" ? (beside distortion and other things but i guess you could call them "noise" too) i mean many talk about dacs outputing "perfect" sinewaves that are same to eachother (or does this just get explained with, "noise isnt audible anymore" ?)

if we are purely scientific speaking this is pretty much the only explanation that can explain "audiophiles" subjectiv expierences (yea sure, placebo is a option too....) IF we are at a point where everything is measurable
maybe everything important is measurable, we just dont aknowledge the influence by it eg "inaudible"

 

[DWI]

It's you demonstrating serious lack of understanding. Do you really believe the more objective orientated people on this forum spend their money on the best measuring equipment without considering it has the features they need and it fits in their interior?

Consumer audio stores sell products that they think their customers want in their homes. If it is a product that is designed with studio monitor performance, like D&D, Kii, ATC or some KEF products, then fine. I've never seen Genelec in a consumer audio store. That tells me all I need to know about its value as a consumer product. They did bring out a consumer range some years ago, but it seems to have been almost completely ignored. But it's a free world, mostly, and you can put in your home what you want.