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The relevance of measurements to audible quality of sound

Thomas savage

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#42
Excellen post, it even has car analogy.. :D

There's only one problem here - that question have already been asked but no answers were given. It seems that some vague consensus about audible threshold limits for various measurement parameters might exist among "elders" on this forum based on their professional experience with audio, but it has not been defined.
Definitely pants on ya head territory but the leg holes should allow for the continued uninterrupted use of headphones, so @Magnum Innominandum should not suffer too much.
 

amirm

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#43
I am hoping the measurement meister himself, Amir would grace us with his take on what is audible and why and how audible for example the SINAD or Noise level differences he measures are in reality and how much we should worry about them and/or base our purchasing decisions upon them.
As much as I am sure you love the answer to that question, it is not the mission I am after!

The purpose of the measurements is to see how well engineered a product is. Less than great engineering sticks out like a sore thumb. Yet many of these manufacturers rave about the high fidelity and great engineering put in them.

There are DACs with SINAD of 85 at > $2,000 and <$100 DACs with SINAD of 110. I know which one I put my money on being best engineered and has highest fidelity to the source.

My job is to weed out empty claims of fidelity and praise the quality of engineering. Without it, not only do you not know how audible the distortions are, but also have no clue how well engineered the product is. My measurements being not only data, but also my experience as an engineer interpreting the data.

That said, reviews also frequently include comments about audibility. There, I apply psychacoustics and identify when some distortion is audible or not. You see that routinely in jitter measurements.

Now, stepping out of high precision products like DACs into amplifiers, there distortion sets in close to clipping and the audible effect is both objectively demonstrated and subjectively (through listening tests) presented.

Pushed to an extreme I don't know that people can hear distortions in a DAC with SINAD of 85. What I do know is that there is no reason to get such performance in a DAC and certainly not paying a ton for it.
 
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Wombat

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#44
This forum has an index/list of tested equipment that is linked to reviews (not this more detailed one). I can't find it. Some help needed, please.
 
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amirm

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#45

Wombat

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#46

Wombat

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#47
HD6XX, currently only headphone. I need them for my home office, listening late at night (wife and new baby), office at work and the like.

Not sure what "seasoning" means.

I listened to HD650 and liked what I heard a lot (so I got the cheaper Massdrop version), but the bass is weak. I tried Bass EQ on my Laptop with the HD6XX but this did not go well. Everything overloaded quickly. I'd like a more real bass if that is possible.

My Speaker Setup I use to listen to music and play movies is an Onkyo AV Receiver with networked audio. Speakers are JBL Control 5 and an active JBL Sub. I figured as they are professional speakers they will be less coloured than many "HiFi" Speakers. This system shames my neighbours Bose Home Cinema which has a very good reputation.

Price range, lower is better. I will spend as much as the 200 USD I paid for the headphones, but if I can get something for less I prefer to pay less.

Preference, good sound. Something that sounds like real music.

I have looked at brands and I am bewildered. Every brand seems to have fanboys that praise it over the moon and detractors that claim to have never heard worse sound ever.

Functionality - go between my laptop, I play Tidal and paid for "Hifi" not that I hear much of a difference on my laptop if any and my Headphone.

Input, I guess from reading USB. But I read of loads of problems with USB, need for additional gizmo's. My laptop has optical out, but I know this is now rare and then next one I buy may not have this.

It's mainly desktop, but should be easy to carry to the main office if I work from there or to clients sites.

That said, I would like to pursue the original thrust of the thread more.

I am disappointed by the state of reliable information to aid purchase decisions in Audio and finding that even places like this that present themselves as objective and science driven are not really that useful in making good choices is disappointing.

How can one decide what to buy? Do we really need to get a PhD in Audio simply to make an informed buying decision? There has to be a better way!

Magnum Innominandum

Some amp. reviews, here: https://audiosciencereview.com/forum/index.php?threads/master-index-for-audio-hardware-reviews.2079/
 
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#48
OP is relevant and one needs psychoacoustics research to pin down the thresholds, limits that are audible (cfr. «Hi-Rez» research).

And somewhat ironically, we are better at defining those limits and measuring when it comes to the peripheral boxes that count the least, and not so good at understanding speakers (in room)!

So ASR reminds us sometimes of the drunkard looking for his keys at night under the light pole.

;)
This an interesting position. But again, we agree then there are limits of audibility and going better does not provide audible benefits?

Do you agree with the limits suggested by andreasmaaan as "conservative" (I understand that to mean even greater levels of deviation from Ideal may be acceptable but to be "very safe" his suggested limits should be met where appropriate?

Magnum Innominandum
 
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#49
Amir,

As much as I am sure you love the answer to that question, it is not the mission I am after!
Thank you for explaining this and for your candor.

It should perhaps made clear (disclaimer) that your measurements aim at evaluating devices in terms of engineering against synthetic benchmarks that have no direct or proven relation to sound quality, lest other people make the mistake of trying to use these measurements as proxy for sound quality and/or to make purchasing decisions.

I agree on not "paying a ton" for a DAC with 85dB SINAD, but, based on discussions here, if a DAC is cheap enough and covers all other bases (colour, shape, enough output for my headphones) then 85dB SINAD is not a deal breaker.

Again, it might help people to understand and make better choices if such issues are clearly spelled out. Kind of like statements of limits in other scientific testing and publications.

Magnum Innominandum
 

amirm

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#50
It should perhaps made clear (disclaimer) that your measurements aim at evaluating devices in terms of engineering against synthetic benchmarks that have no direct or proven relation to sound quality, lest other people make the mistake of trying to use these measurements as proxy for sound quality and/or to make purchasing decisions.
I have written a tutorial for my old analyzer which I need to update but that, and the FAQ after it clarify everything about my work: https://www.audiosciencereview.com/forum/index.php?threads/understanding-audio-measurements.2351/. There I comment on usefulness of measurements for audibility, etc.

For now, what you state is not what I said. I actually said that I am able to interpret measurements with respect to audibility and do that routinely in the reviews. The reviews have a ton of information and not just a SINAD number. That information with the right knowledge of psychoacoustics provides a lot of insight into audibility in general. I hope members learn the same concepts over time and able to interpret the measurements with respect to audible effects.

And it certainly is NOT wrong to use the measurement for purchasing intent. If a restaurant has a health rating of A versus F, that doesn't enter your decision making as to whether you eat there or not?
 

amirm

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#51
Remember this:

There is very wide variability in everyone's ability to hear non-linear distortions (i.e. something other than frequency response variations). I can't make objective remarks on everyone's behalf with respect to inaudibility of distortion unless, I take it to the mathematical and objective extreme which calls for a 116-120 dB distortion and noise-free dynamic range. See this article on that: https://audiosciencereview.com/forum/index.php?threads/dynamic-range-how-quiet-is-quiet.14/

The moment you move from that position, you get into the gray area of how much distortion, what kind of distortion, what music, what playback level, and which listener. I try to stay away from that strive to find devices that meet the above target close enough as to none of this analysis mattering.
 

Blumlein 88

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#52
I have written a tutorial for my old analyzer which I need to update but that, and the FAQ after it clarify everything about my work: https://www.audiosciencereview.com/forum/index.php?threads/understanding-audio-measurements.2351/. There I comment on usefulness of measurements for audibility, etc.

For now, what you state is not what I said. I actually said that I am able to interpret measurements with respect to audibility and do that routinely in the reviews. The reviews have a ton of information and not just a SINAD number. That information with the right knowledge of psychoacoustics provides a lot of insight into audibility in general. I hope members learn the same concepts over time and able to interpret the measurements with respect to audible effects.

And it certainly is NOT wrong to use the measurement for purchasing intent. If a restaurant has a health rating of A versus F, that doesn't enter your decision making as to whether you eat there or not?
I would like what the OP is asking for, but things are complicated.

Where I live an F health rating gets you shutdown. So only C or better places are open for business. And the Op wants something like that for audio. Buy this component with this fidelity rating of C or better and you'll get all the fidelity you can hear. It is too complex a question in general right now to pick between A and C level fidelity.
 
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#53
It should perhaps made clear (disclaimer) that your measurements aim at evaluating devices in terms of engineering against synthetic benchmarks that have no direct or proven relation to sound quality, lest other people make the mistake of trying to use these measurements as proxy for sound quality and/or to make purchasing decisions.
I think you are making a huge assumption about the term "sound quality" that you keep using. It seems that you are using this as some form of universal benchmark that is somehow unquestionable. But it appears that, for you, it is defined as perceptual only and perception is a real can of worms . . .

As @solderdude has stated, for many of us "sound quality" is equivalent to "fidelity to the source". We want to know how linear a device is -- the absence of distortions, additive noise, etc. is a sign of its linearity and therefore its quality. By feeding in known signals and measuring the output, we can ascertain how the output differs from the input. It really is a simple concept, though the terminology and underlying science might seem complex.

Measurements are not a "proxy for sound quality" since we are considering "sound quality" as something that is not purely perceptual but can be defined and measured.
 
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#54
I would like to thank everyone for their input. It has been very interesting.

I have at least derived some sense here. I should look for a Headphone Amp (with or without DAC open at this point) with the following requiremenmts:

105dB Peak SPL midband and the ability to EQ the HD6XX to the Harman Target Curve from it's original Response found here:

https://www.innerfidelity.com/images/MassdropHD6XX.pdf

105dB peak need 0.86V.

The target requires +3dB @ 20Hz while the Headphone measures - 15dB, so 18dB extra output are required to allow for the EQ.

Thus 0.86V * 18dB (8x) = 6.88V, our amplifier should support at least 7V output. This seems a surprisingly high figure, but is a result of the required EQ.

It would be good, I think, to handle most of this EQ in the analogue domain. If done digitally we would need to attenuate the signal by 18dB to avoid the potential for clipping, which seems to have the potential of trouble, especially with less expensive equipment.

I think it would be possible to make a special cable with a passive EQ build in, but my soldering is not very good, I'd need someone to make this for me.

So we now have:

Headphone Amp with:
7V minimum output
Bass EQ 18dB at 20Hz
Optionally USB connected DAC
Price below 200 USD

Does anything come to mind?

Magnum Innominandum
 

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#55
Do headphones cope with that amount of bass boost? It does seem a lot. Another headphone may be a better choice for 20Hz performance, if there are any that go so low.

Also consider long term hearing degradation affect.
 
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#56
Do headphones cope with that amount of bass boost? It does seem a lot. Another headphone may be a better choice for 20Hz performance, if there are any that go so low.

Also consider long term hearing degradation affect.
The HD650 is rated as 500mW (300 Ohm) meaning it should handle 12V input, we should be on the safe side as far as I understand this sort of thing.

The bass boost is needed because the bass is attenuated this much on the headphone. So it will not cause excess SPL, but merely the correct level of bass.

I am using the 105dB peak SPL based on the THX Playback recommendations. My Home theatre is set up for this, to match the original sound mixing stage levels. For 105dB Peak SPL you get around 85dB average level with well recorded music, at the loudest passages. This generally considered safe for hearing.

Magnum Innominandum
 

BE718

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#57
Hello,

In this forum we see specific measurements posted regarding many devices.

Recommendations are made on the basis of these measurements. All very scientific, which I like.

I mean who would buy a Car on a vague concept "how it drives"?

We know top speed, torque, mpg etc. and can rely on these together with convenience features (how many cup holders, size of the trunk and how easy to access) a shape and colour that pleases us to get a good choice.

No need to test drive, right?

Now with a car I can follow the value of these measurement numbers. I can understand why a car with good torque, top speed, mpg and convenient layout would be reasonably recommended over one that falls down in one or several of these areas, though it has not stopped the buying public from buying inconvenient and inefficient cars, myself included and yes, I test drive and decide ultimately on many factors including how it feels driving on what I buy.

While the measurements presented here seem of a similar kind (Distortion, Noise, Jitter), I would ask for the scientific background.

If we elevate specific qualities as a measure of the recommendability of a device to listen to music with, there ought to be good scientific evidence that shows that lower distortion is always better sounding, that lower noise is always better sounding and I mean not in a relative sense as in: "Above a certain limit lower distortion always sound better" or "Above a certain limit lower noise always sounds better", but in the absolute sense in which it is presented here.

Alternatively, if these is a consensus about what levels of distortion, noise and jitter are actually audible, it would be interesting to know what they are and how tested devices results compare to those limits.

Also, if there are such limits and all tested devices are below the audibility threshold, should recommendations based on the measurements still be made?

Ideally the proponents of "low distortion uber alles", "low noise uber alles" and "low jitter uber alles" simply have reliably scientific tests to present that support their position and then we can continue measuring and recommending on this basis. My own research failed to provide such tests and evidence, however surely no-one scientific inclined would test result based recommendations without good and solid evidence that these test results are meaningful in the context.

Magnum Innominandum
The issue here for me is there is an implied suggestion that better fidelity is not the ultimate goal. The car analogy is faux. When you are examining a cars technical performance the question is not "do you like it", it is purely about how well it objectively does things, power, torque, grip, nvh, fuel economy etc. It is not about your emotional reaction to it which is coloured and biased by all sorts of factors.

The context is simple. Do we have difinitive defined limits for audibility thresholds of all technical parameters? No. However we do have a lot of information about it and know how to test under controlled conditions to explore it. Regardless of this the objective is still to obtain highest fidelity, that really does mean lowest distortion, noise etc etc.

The recommendation then follows from a price performance evaluation. Buy a cheap high performance device V buy an expensive low performance device. We have seen both, no names mentioned (cough schiit).....

If an individual then wants to bring emotion into this, that's their decision. So if an individual is convinced Schiit products are better for whatever reason that's their perogative, but we can still objectively comment about its performance. The individual does need to be extremely cautious regarding the fallibility of uncontrolled listening comparisons however.

If at the end of the day someone can't hear the difference between two products but like tge look and feel of one over the other then that's fine, the point is they have made an informed decision, which is what this site is about.
 

BE718

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#58
All I want and need is reliable information to help me make the right purchasing decision for a DAC/Amp for my Massdrop Sennheiser Headphones.

It seems that other having enough output to drive them there is nothing to be gleaned from the measurements here that helps. That is quite dispiriting.

Magnum Innominandum
That is simply not true, that is simply a case of you not understanding the information, but we can help with that.
 

BE718

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#59
HD6XX, currently only headphone. I need them for my home office, listening late at night (wife and new baby), office at work and the like.

I listened to HD650 and liked what I heard a lot (so I got the cheaper Massdrop version), but the bass is weak.

I tried Bass EQ on my Laptop with the HD6XX but this did not go well. Everything overloaded quickly. I'd like a more real bass if that is possible.

My Speaker Setup I use to listen to music and play movies is an Onkyo AV Receiver with networked audio. Speakers are JBL Control 5 and an active JBL Sub. I figured as they are professional speakers they will be less coloured than many "HiFi" Speakers. This system shames my neighbours Bose Home Cinema which has a very good reputation.

Price range, lower is better. I will spend as much as the 200 USD I paid for the headphones, but if I can get something for less I prefer to pay less.

Preference, good sound. Something that sounds like real music.

I have looked at brands and I am bewildered. Every brand seems to have fanboys that praise it over the moon and detractors that claim to have never heard worse sound ever.

Functionality - go between my laptop, I play Tidal and paid for "Hifi" not that I hear much of a difference on my laptop if any and my Headphone.

Input, I guess from reading USB. But I read of loads of problems with USB, need for additional gizmo's. My laptop has optical out, but I know this is now rare and then next one I buy may not have this.

It's mainly desktop, but should be easy to carry to the main office if I work from there or to clients sites.

That said, I would like to pursue the original thrust of the thread more.

I am disappointed by the state of reliable information to aid purchase decisions in Audio and finding that even places like this that present themselves as objective and science driven are not really that useful in making good choices is disappointing.

How can one decide what to buy? Do we really need to get a PhD in Audio simply to make an informed buying decision? There has to be a better way!

Magnum Innominandum
My understanding is that the 650 and 6xx measure identically barring sample to sample variation, so I'm afraid my first question is your subjective evaluation correct?
 
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BE718

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#60
Amir,

Thank you for explaining this and for your candor.

It should perhaps made clear (disclaimer) that your measurements aim at evaluating devices in terms of engineering against synthetic benchmarks that have no direct or proven relation to sound quality, lest other people make the mistake of trying to use these measurements as proxy for sound quality and/or to make purchasing decisions.

I agree on not "paying a ton" for a DAC with 85dB SINAD, but, based on discussions here, if a DAC is cheap enough and covers all other bases (colour, shape, enough output for my headphones) then 85dB SINAD is not a deal breaker.

Again, it might help people to understand and make better choices if such issues are clearly spelled out. Kind of like statements of limits in other scientific testing and publications.

Magnum Innominandum
I'm afraid I take issue with your statement here. Fidelity to the original signal is directly related to sound quality. Any individuals perception limits or preferences or biases are neither here nor there.

Don't make the mistake of conflating two different issues, product performance and personal preference.
 
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