Headphone Measurements Using Brüel & Kjær 5128 HATS

[zermak]

As said, interpretations vary here on the accuracy argument and exact causation, but whatever the case, it's not going to be a matter of a single linear compensation between the two - note the plots in the PDF I attached earlier, the low-frequency variation is unit specific because it reflects a difference in acoustic impedance. What's sort of troubling is that it's rather annoying to accurately measure eardrum SPL with IEMs, so getting a definitive answer on which coupler better approximates the human case is difficult.

That was my point. I mean this is a kinda SOTA HATS and yet we struggle. But Amir experience can come handy too. He could set up some test on himself to see if the RAW datas relate with what he hears comparing the RAW with the other HATS (even if there is the different headphone variable too). He could do the same for the peaks/dips over 10kHz I suppose.

 

[ZolaIII]

Every design of course have it's own limitations, regarding this curve i would like to see Aurvana Air earbuds & Aurvana Trio EMI's as I think they are well suited to it. I know there's not much time but subjectiv listening opinions would be appreciated.
Best regards.

 

[bobbooo]

This chart does not show at the long end what I would call absorbing/diminishing, the courses totally change!!

Silicone tips look all equal to me more or less, but foams are very different within the class, some are stiffer, other are less firm.

Yes the treble is not easily predictable when changing to foam tips, but there is usually a diminishment above ~10kHz, and I've never seen a significant change in the bass - see the many IEMs measured with both stock silicone and various foam tips by Speakerphone/ClarityFidelity that show this.

 

[amirm]

Beats ep measurements:

How the heck does one position a Supra-aural (over the ear) headphone like this???

Wonder if she would smile the same across all of the above positions.

Here is a shot at compression test at different frequencies:

Unless there is some feedback, I will likely go with 100 Hz.

 

[amirm]

Another over the ear, Sony MDR-ZX110 measurements:

Unless there is a trick I don't know about, bass measurements is just not accurate. How was this managed in listening tests or others who show much less variations????

 

[Doodski]

Another over the ear, Sony MDR-ZX110 measurements:

View attachment 78561

Unless there is a trick I don't know about, bass measurements is just not accurate. How was this managed in listening tests or others who show much less variations????

Perhaps the supplier of the HATS system can contribute.

 

[amirm]

This one is over the ear and still has massive variations: Mpow H10ANC (ANC off)

At least the measurements show a severe dip at 650 Hz so good info is there to be had.

 

[Hugo9000]

If you have a friend who enjoys obsessively fiddling with tiny changes in loudspeaker positioning, now you know a few models of headphone to give him/her as gifts! Or someone who distrusts EQ but still would like to 'fine tune' sound, some of those are perfect, it's like getting a dozen different headphones in one, depending on how you wear it!

Otherwise known as "is it a bug or a feature?" haha

 

[amirm]

AKG K371 measurements. This one fits really well although there still variations:

This one is supposed to hug the Harman curve. I had the labels swapped in the last two measurements which I just fixed.

I guess if we sit far enough back, and average a ton, it does track Harman curve.

 

[Mad_Economist]

Unless there is a trick I don't know about, bass measurements is just not accurate. How was this managed in listening tests or others who show much less variations????

In situ on a human head, you'll see a bit less variation because the nerves in our ears and cheeks let us tell when things are sitting askew or our pinnae are folded at weird, coupling-breaking angles. As I suggested before, a continuous or repeating stimulus while mounting the headphones initially (noise and some real-time spectrum view being my preference) to get "reasonable" coupling is a useful trick, particularly when you're new to putting headphones on dummies.

Edit: FWIW, RTings uses intraconcha mics for bass measurements on human heads for this purpose - I use an open canal microphone I constructed for the same purpose myself. It's a useful "sanity check" when the HATS results are extreme.

 

[amirm]

As I suggested before, a continuous or repeating stimulus while mounting the headphones initially (noise and some real-time spectrum view being my preference) to get "reasonable" coupling is a useful trick, particularly when you're new to putting headphones on dummies.

I know about this but what is the reality? Who wears their headphones using measurements for positioning???

Seems to me such a thing is either a design flaw or measurement flaw. Having a review site use many means to minimize variation hides a real phenomenon. The goal shouldn't be how to hide as many variations and make things pretty. Or should it?

 

[Mad_Economist]

I know about this but what is the reality? Who wears their headphones using measurements for positioning???

Seems to me such a thing is either a design flaw or measurement flaw. Having a review site use many means to minimize variation hides a real phenomenon. The goal shouldn't be how to hide as many variations and make things pretty. Or should it?

IMO substantial weakness to coupling variation is an inherent - albeit unavoidable, for many principles of operation - design flaw in headphones; a compromise at minimum.

This said, I've spent enough time with microphones in my own ears to be pretty confident that "normal wear" approximates a better condition of coupling than you get putting things onto a HATS unassisted, barring some congenital numbness of the ears and face. IMO there's merit to capturing both the variation we see in edge cases, and a "normal" case that approximates behavior on the measurement engineer's head (or, ideally, as with RTings, a small group of volunteers might be measured, but this is really a PITA).

 

[Doodski]

I know about this but what is the reality? Who wears their headphones using measurements for positioning???

Seems to me such a thing is either a design flaw or measurement flaw. Having a review site use many means to minimize variation hides a real phenomenon. The goal shouldn't be how to hide as many variations and make things pretty. Or should it?

Repeatability is the goal and expectation for this expense. It must be very complicated or a goofy apparatus.

 

[RayDunzl]

Those headphones are tunable.

That's all.

 

[Mad_Economist]

Repeatability is the goal and expectation for this expense. It must be very complicated or a goofy apparatus.

If you're a glasses wearer, have you ever had someone put on or take off your glasses for you? Putting headphones on another head is approximately equally awkward; you do get better at it, but it's a learning curve for sure.

 

[Mad_Economist]

Here is a shot at compression test at different frequencies:

View attachment 78558

Unless there is some feedback, I will likely go with 100 Hz.

I have only infrequently encountered headphones which displayed "power compression" outside of bass frequencies. A 100hz tone stepped in level would be a pretty reasonable compromise - if you wanted to be extra thorough to detect potential problem areas, doing sweeps at a "low" level (say 90-95dB re: 500hz or so) and a higher level and normalizing the second result to the first can show frequencies that aren't going well. Soundstage does this with its NRC speaker measurements, the plots look like so:

Edit: Note that for obvious reasons it is extremely important that the acoustic output level of the headphones be known during any test of linearity.

 

[Doodski]

If you're a glasses wearer, have you ever had someone put on or take off your glasses for you? Putting headphones on another head is approximately equally awkward; you do get better at it, but it's a learning curve for sure.

Makes sense. I am a glasses wearer and I've experienced different opticians and optometrists putting them on my head. Some are much better than others. I have Sennheiser HD 598 SRs and they seemingly sound the same wherever I wiggle them to be if not pushed into unreasonable positions that are obviously out of bounds. If a headphone req's extensive experimentation with positioning I consider that a fault. Like the Koss Porta Pro as good as it is when positioned justtt right.

 

[Mad_Economist]

Makes sense. I am a glasses wearer and I've experienced different opticians and optometrists putting them on my head. Some are much better than others. I have Sennheiser HD 598 SRs and they seemingly sound the same wherever I wiggle them to be if not pushed into unreasonable positions that are obviously out of bounds. If a headphone req's extensive experimentation with positioning I consider that a fault. like the Koss Porta Pro as good as it is when positioned justtt right.

A major - and, strangely, not very widely exposed to the general public - advantage of "open" designs is their relatively low variation with "normal" leaks. The HD598 likely shows differences mostly below 100hz with positioning (where the ear is very insensitive), whereas you can see how ill-behaved some of the small sealing on-ear designs Amir's measuring are.

 

[March Audio]

Here is Hifiman HE-400i. I am not annotating these graphs in the interest of time:

View attachment 78331
Compensated:
View attachment 78332

What do we think? Is that peaking between 6 and 10 kHz real?

I have a pair of HE4xx. I havent measured them but my ears certainly tell me they have this peaking. I detest the things.

 

[magicscreen]

So we don't NEED to target that curve

"The problem is, by the time outside sound gets to your ear drum it's not flat any more. Our brain is used to hearing sound with this non-flat ear drum response. When we measure headphones we have to know very precisely what that non-flat ear drum response is so that it can be subtracted from headphone measurements to return them to a flat line for evaluation."
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