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ASR Getting Into Measuring Headphones!

solderdude

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Wouldn't that need to be a destructive test to be accurate?

When you know the efficiency and power rating (not always specified by manufacturers) you can calculate the max. SPL.
Could be off 1 or 2 dB but that's moot.
I already did this for most fairly well known on- and over-ears (Max SPL colomn).
 

MZKM

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When you know the efficiency and power rating (not always specified by manufacturers) you can calculate the max. SPL.
Could be off 1 or 2 dB but that's moot.
I already did this for most fairly well known on- and over-ears (Max SPL colomn).
That’s of course if the specs are technical and not marketing.
 

tvrgeek

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Don't buy the weight at all. It depends on how it is supported and how it sits against the side of your head. Some could wear Pro-4 AAs all day, I could stand them for less than half an hour, yet I can wear heavy ear muffs in my shop all day. My Senhiesters were not comfortable, but my Yamaha YH-1s are only after I modified the head strap.

The test set can give us relative measures of distortion and energy storage. It can give us "suitability" as far as amplifier compatibility and what it takes to reach some fixed threshold, like 100 dB maybe. Max SPL does not matter as most are capable of permanent damage to your hearing. I really don't care if one set gives 110 dB and the next 120. If more interest would be it there was some safety limit and how it behaved.

No, cans are one product you really need to try on. Consistent testing can narrow the field and that would be a very great service. Well, people do buy shoes online. Maybe I am outside 3 standard deviations.
 

Francis Vaughan

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They show you redundant data though. Note how the frequency response were responsible for elongation in time:
Well most the plots show redundant data. Just publish the impulse response and be done. It is all there. Just a trifle useless. The trouble with waterfall plots is that people read too much into them. There is the look of more data than a frequency response, and scary looking ridges and valleys. So people obsess about them. But they do display the data in a useful manner, so long as you restrict yourself to looking for that additional insight. Just eyeballing a FR won't always easily tell you the reason for a given peak or hole. The waterfall is useful for differentiating aspects of the response in an easy to digest form. Which is, I suspect, another way of saying that they are useful in specific circumstances. I like to see them, as I can quickly eyeball them and decide what to ignore.

What would be really interesting is to see if we can get the transfer function of the headphones. For that we need the real and imaginary parts of the harmonic distortion, aka amplitude and phase. I think the AP can give you this. I had a bit of a look through the manual, but there is a lot to digest. If we had both parts from the FFT of the distortion measurement, it is possible to reconstruct the transfer function, and then derive some of the subjective distortion metrics. The Gedlee metric first up, but also that by Eric Mario de Santis and Simon Henin, which is heavily based upon human perceptual models, and physiology. This may go a long way to providing some science to the question of comparing different distortion performances.
 

the_brunx

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:facepalm:

Tyll Hertsens measured headphones from the very beginning of audiophile headphones being a "thing" and reviewers never had a problem finding an audience. One more person with a slightly more accurate rig does not a revolution make.


an audience they will find, but a blind following, not anymore.
no disrespect to tyll but his measuerements were not so well laid out for normal people to understand what they mean. and I dont think he did sinad measurements or distortion vs power/loudness, which are the most important in my opinion.
 
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solderdude

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I dont think he did sinad measurements or distortion vs power/loudness

Tyll did measure distortion at 90dB and 100dB SPL
Much lower levels don't make sense as noise from the environment and test rig will be prevalent.
Amir will have to build a soundproof chamber, especially for low frequencies to get meaningfull numbers with planars.

There isn't a single SINAD number for headphones, besides at 1kHz most headphones perform pretty well. It is lower frequencies and headphone specific higher frequencies which are the problem with headphones.
 

the_brunx

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can't wait for a ranking chart for headphones. I know that's coming too.
 

wasnotwasnotwas

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can't wait for a ranking chart for headphones. I know that's coming too.

I'm not so sure. Which one metric do you rank on? SINAD might be best for electronics but far from the complete picture. I think we might just have to make do with recommended or not.
 

DualTriode

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Tyll did measure distortion at 90dB and 100dB SPL
Much lower levels don't make sense as noise from the environment and test rig will be prevalent.
Amir will have to build a soundproof chamber, especially for low frequencies to get meaningfull numbers with planars.

There isn't a single SINAD number for headphones, besides at 1kHz most headphones perform pretty well. It is lower frequencies and headphone specific higher frequencies which are the problem with headphones.

I am thinking an old refrigerator with treatments or Constrained Layer Damping drywall.

https://nationalgypsum.com/file/THESOUNDBOOK.pdf
 

solderdude

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can't wait for a ranking chart for headphones. I know that's coming too.

Crinacle, Rtings and Jaakko have ranking charts, they all differ immensely. Obviously not everyone ranks them the same. I rank them yet differently.
So while there are rankings they are just that. One can assume one is right and others are not but reality is they all are not correct. They are just ranked based on certain properties.
Besides, as wasnotwasnotwas already mentioned. Such charts only make sense per use case (Rtings does rank this way)
 
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bobbooo

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can't wait for a ranking chart for headphones. I know that's coming too.

We already have that:

https://github.com/jaakkopasanen/AutoEq/blob/master/results/RANKING.md

Ranking based on Oratory's and Crinacle's measurement data using Harman's predicted preference rating formula, which has a correlation of 0.86 and 0.91 (1 being perfect) between predicted and actual preference ratings of over-ear and in-ear headphones respectively in double-blind, scientifically controlled tests. I like how that ranking table breaks down the preference rating parameters into individual columns too, with the 'slope' column particularly useful (> 0 being brighter sounding, < 0 darker, and ~0 indicating a neutral overall tonal balance).
 
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Robbo99999

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Comfort is such a critical component of the overall headphone experience. Many aspects are subjective but some values can still be expressed objectively: clamping pressure/force and earpad dimensions are two major factors in comfort that never get expressed. What do you guys think of adding data like that to the reviews?
Even if we could measure such things, translation into personal comfort will be tough. I am open to ideas though.
Somewhat related to comfort, but more related to usability would be the earcup size of the headphone, it would be very useful to have measurements of the inner diameters of the earcup so that buyers can be clear on if the headphone will fit over their massive lugs! :D

This is false. Resolve (Andrew Park) does his own measurements for headphones.com. Crinacle's measurements are completely separate to those. Source:

https://forum.headphones.com/t/hifm...-magnetic-headphones-official-thread/3248/209
Does he have a database of his measurements? I remember trying to find it a few months ago & couldn't find anything.
 
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amirm

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What would be really interesting is to see if we can get the transfer function of the headphones.
Unfortunately this is highly level dependent as you likely know. I will look into exporting impulse data....
 

bobbooo

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Does he have a database of his measurements? I remember trying to find it a few months ago & couldn't find anything.

Yeah I couldn't find a database of them all together either. You just have to search through headphones.com's reviews here at the moment.
 

bobbooo

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Wow! What a difference from the HE400i (Mine :()

Don't worry, nothing in those CSD plots will have any audible effect that cannot already be seen in the headphone's frequency response. The latter, excess group delay and nonlinear distortion are all you really need to fully characterise a headphone's audible performance, in that order of importance.
 
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the_brunx

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I’m rooting for a headphone ranking chart based on distortion/ sinad. So far it’s been great with everything else. But recommendations based on when everything else is also factored in.
 

RayDunzl

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I’m rooting for a headphone ranking chart based on distortion/ sinad.

@amirm

I'd like to see the no-signal noise floor of the measurement rig.

Maybe comparisons with closed back, open back, and no headphone at all, whereever the testing location will be.
 

bobbooo

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I’m rooting for a headphone ranking chart based on distortion/ sinad. So far it’s been great with everything else. But recommendations based on when everything else is also factored in.

The science shows that nonlinear distortion plays a minimal role in perceived sound quality of headphones e.g. see this paper by Steve Temme and Dr Sean Olive:

https://www.aes.org/e-lib/online/browse.cfm?elib=17441

Quotes from the paper:
none of the headphone distortion measurements could reliably predict listener preference ratings based on audible distortion

The linear distortions [i.e. frequency response errors] in headphones are orders of magnitude higher and more audible than the nonlinear ones

Nonlinear distortion in headphones of this high caliber (Headphone D excepted) seems to not be a significant factor in how good it sounds

this study provides further experimental evidence that traditional nonlinear distortion measurements are not particularly useful at predicting how good or bad high caliber headphone sounds

Basically, nonlinear distortion is only really noticeable if it's pretty bad, just as is the case with speakers, and DACs, amps etc. It's more of a pass/fail metric than any useful guide to a sound quality scale.
 

the_brunx

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The science shows that nonlinear distortion plays a minimal role in perceived sound quality of headphones e.g. see this paper by Steve Temme and Dr Sean Olive:

https://www.aes.org/e-lib/online/browse.cfm?elib=17441

Quotes from the paper:








Basically, nonlinear distortion is only really noticeable if it's pretty bad, just as is the case with speakers, and DACs, amps etc. It's more of a pass/fail metric than any useful guide to a sound quality scale.

Tell you the truth. I don’t care that it’s barely perceivable. I just want to know/have the best „instrument“ out there. I guess a little bit of the same reason why people buy fast cars but rarely if ever even hit half of those speeds which are capable.
 

bobbooo

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Tell you the truth. I don’t care that it’s barely perceivable. I just want to know/have the best „instrument“ out there. I guess a little bit of the same reason why people buy fast cars but rarely if ever even hit half of those speeds which are capable.

It's not that nonlinear distortion levels are barely perceivable, it's that for the large majority of headphones, they're imperceptible. Like the DAC/amp SINAD charts, above the lowest red tier the numbers are purely an engineering metric with no relevance to the end user or sound quality. If we have to do ridiculous audio/car metaphors, then it would be like having a (autonomous) car that can travel faster than any other ever built, but only at top speed when you're asleep so you can never perceive it, and only in a continuous round trip at that speed so it can't take you anywhere faster than a normal car. In other words, pointless.
 
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