Headphone Measurements: The New Standard, Part 1
Jan 8, 2021 at 9:41 AM Post #76 of 88
The personal variance of ear canal anatomy above 8kHz is so wide, that no amount of generic single dummy-head measurement can ever approximate the what it really sounds to YOUR ears.



Still, the development of less variance in headphone measurements is important and very welcome.

Now, if we could actually simulate differences in "normal" ear anatomy and have a range of measurements that show how differently a pair of headphones can sound on different heads/ears, that would be the next step.
the problem is that for each inner ear anatomy the subject hears the distortion as "normal"---if they hear a live performance the sound is put through the ear anatomy and processed by their ear anatomy just like every other sound they hear. if you corrected this to an ideal ear anatomy the person would hear a sound that is totally abnormal for their brain to receive and would not be pleasant or realistic. This would not be true for bone conduction phones which would have to be balanced to reproduce the distortion of each persons ear canal in order not to be sensed as alien.

JRF
 
Apr 1, 2021 at 4:47 AM Post #78 of 88
Have not found Part 2. Does it exist?

No, @anli, not yet, sorry. Much of what I intended to cover in it was summarized in this video:


If you can't see the embedded video above, please click here.

However, as we've gained much more experience with (and done many more measurements on) the 5128, there are other observations we'd like to share that could have only come with more experience and measurements. A Part 2 will have to be a combination of text and video content.
 
Nov 24, 2021 at 11:33 PM Post #80 of 88
No, @anli, not yet, sorry. Much of what I intended to cover in it was summarized in this video:


If you can't see the embedded video above, please click here.

However, as we've gained much more experience with (and done many more measurements on) the 5128, there are other observations we'd like to share that could have only come with more experience and measurements. A Part 2 will have to be a combination of text and video content.

Both are quite good and informative. The ultimate results remain both subjective to an objectively designed source.
 
Jan 1, 2022 at 7:27 PM Post #82 of 88
Many people find them not good.
The OG HD800 were very good for reference work for older genres without need for deep sub bass extension. The HD800S addressed many of their problems, but BeyerDynamic/AKG/etc still did sub extension better on their respective flagships.
 
Jan 1, 2022 at 7:33 PM Post #83 of 88
I've listened to a lot of headphones and the Sennheiser HD700, HD800, HD800S, HD820 - all of them - sound more "real" to me than anything else I've ever heard before. Is this model able to capture whatever I am hearing? The HD820 is the best overall I've ever heard to date, period, and traditional measurements don't seem to capture the magic of most of this lineup.
I’m curious as to what about the HD820 you find better than the HD800S. I strongly feel the HD800S is BY FAR Sennheiser’s greatest achievement ever, and that the HD820 was released before it was finished.
 
Jan 1, 2022 at 7:52 PM Post #84 of 88
No, @anli, not yet, sorry. Much of what I intended to cover in it was summarized in this video:


If you can't see the embedded video above, please click here.

However, as we've gained much more experience with (and done many more measurements on) the 5128, there are other observations we'd like to share that could have only come with more experience and measurements. A Part 2 will have to be a combination of text and video content.

Aye Jude,

Do you have a massive backlog of cans intended for a full comprehensive analysis, learning from the mistakes of past headphone graph personalities ?

If you haven’t added these in the queue or measured them yet, I nominate:

Focal Utopia
Focal Stellia
Focal Clear MG Pro
AKG K812 Pro
AKG K872
BeyerDynamic DT-1990 Pro
BeyerDynamic Amiron series
BeyerDynamic TYGR 300 R
(All 3 of these Beyers with Dekoni Elite Velour pads)
Sennheiser HD660S
Pioneer SE Monitor 5
Sony MDR-V6
Sony MDR-V6 with BeyerDynamic DT250 velour pads
Sony MDR-V6 with Yaxi StPad2
Sony MDR-CD900ST
Sony MDR-CD900ST with Yaxi StPad2
Sony MDR-M1ST
Sony MDR-M1ST with Yaxi M-ST pad

Peace & blessings to you and yours in the new year brother !
 
Last edited:
Oct 29, 2022 at 1:54 AM Post #86 of 88
This is not a "standard" yet. There's no research nor validation for a reference with the specifications of this device to declare it a new "standard"...

There's a 2003 report titled Background Information On Head And Torso Simulators And Relevant Standards that was prepared for the project Ear simulators and hearing aid testing to examine how the standards relate to each other, and how the HATS (head and torso simulators) from various manufacturers conform to the standards. This project was part of what was then the United Kingdom's Department of Trade and Industry, through their National Measurement System Program for Acoustical Metrology, undertaken by the National Physical Laboratory (NPL) and the Institute of Sound & Vibration Research (or ISVR)

Among the findings:

6824-R01 - ISVR BULLET 3.jpg


  • In this specialized field, the standards appear to have been led by the hardware, not vice versa.
  • It would possibly be more accurate to say that a particular standard conforms to a particular HATS, not that the HATS conforms to the standard.
  • Slight deviations from and "minor adjustments" to the standards, and revisions between different versions of the same standard, suggest that manufacturers continue to lead with the standards left to follow.
This is how the IEC 60711 standard came about. The first 711 simulator (the Brüel & Kjær Type 4157) was released a year before the standard was established.

The Brüel & Kjær Type 4620 ear simulator in their Type 5128 head and torso simulator is now standardized as the Type 4.3 artificial ear in Recommendation ITU-T P.57 (https://www.itu.int/rec/T-REC-P.57-202106-I/en).

Side note: Interestingly, it's also said in this 2003 paper that "The IEC 60711:1981 standard gives no clues as to the development or scientific basis of the device it describes." I do now have this information, have presented it in my talk titled "Evolution Of Hearing Simulation, And An Examination Of Frequency Response Targets And How We Use Them" (presented at CanJam London and CanJam SoCal this year, and to be presented again at a few of the CanJams next year), and will post about it in this forum later.

As further validation of the research that led to the B&K 5128 (Type 4.3), HEAD acoustics, for their latest such measurement manikin (Head Acoustics HMS II.3 LN HEC) adopted the same pinna, concha bottom, and ear canal entry from Type 4.3 (based on the average adult human canal research from Brüel & Kjær et al.) up to Type 4.3's reference plane (the plane from which Type 4.3's published transfer impedance is measured for the standard (between it and the DRP)).

The HEAD acoustics HMS II.3 LN HEC is now standardized as the Type 4.4 artificial ear in Recommendation ITU-T P.57.

Beyond Type 4.4's reference plane, there are differences between Types 4.4 and 4.3, described thusly in the 4.4 standard:

The remaining inner part of the ear canal between reference plane and DRP is based on [IEC 60318-4], and consists of a transition piece and a cylindrically shaped cavity.

The type 4.4 artificial ear can be used for all types of devices, except for deep intra-concha or insert devices, which extend beyond the reference plane. In such cases, the type 4.3 ear simulator shall be used.

Because of these differences (described in the quote immediately above), the published transfer impedance measured between the reference plane and the DRP for Type 4.4 is slightly different than that in 4.3, but, for the most part, is identical.

Again, in this specialized field, the standards are led by the hardware, and I think that HEAD acoustics' adoption of the research that led to Type 4.3 for the ear simulator in their HMS II.3 LN HEC (Type 4.4) serves as a strong validation of the research behind the Type 4620 ear simulator in the Brüel & Kjær Type 5128 (Type 4.3).

Also, it seems many (if not most) of the measuring reviewers are also transitioning to measuring with the Brüel & Kjær Type 5128 manikin, or the Type 4620 ear simulator (without the full manikin).

...So it is strange to acquire this device if you are not going to do scientific research with it.

We are far along now in developing a tool to display our measurements on Head-Fi. We'll start with measurements from the 5128, and will later add at least some of our previous GRAS 45CA measurements, too. (Unless otherwise stated, all will be multi-seat averages.)

Also, we've recently been using the Brüel & Kjær Type 5128 head and torso simulator with HEAD acoustics' labCORE hardware and ACQUA test software, testing with HEAD acoustics' recently released MDAQS instrumental audio quality evaluation. From their description of MDAQS:
Audio quality is not only about linear frequency response. Human perception subconsciously evaluates several other quality dimensions. MDAQS takes these factors into account and evaluates focus attributes that determine the overall quality, creating the world’s first binaural perception-based measurement tool that assesses device audio quality in a scientific and quantifiable way.

Also from HEAD acoustics on MDAQS:
In our basic investigations, we found that three primary quality dimensions fully account for human perception of sound quality:
  • Timbre: how faithful is the spectrum reproduced, and how good is the temporal resolution?
  • Immersiveness: how well are virtual sound sources defined in three-dimensional space?
  • Distortion: how unimpaired by adverse influences, i.e., how "clean" is the sound signal?

There are a lot of very compelling things to talk about with respect to MDAQS, but we're in early days with it now.

Almost daily we're in touch with industry folks (remotely and in person), and the topic of audio measurements is probably what we talk about most. A couple of days ago, we had an industry visitor for the day, discussing novel measurement methods (in the context of their products, which may require novel measurement methods to fully evaluate).
 
Last edited:
Oct 29, 2022 at 10:45 AM Post #87 of 88
This is how the IEC 60711 standard came about. The first 711 simulator (the Brüel & Kjær Type 4157) was released a year before the standard was established.
Also, it seems many (if not most) of the measuring reviewers are also transitioning to measuring with the Brüel & Kjær Type 5128 manikin, or the Type 4620 ear simulator (without the full manikin).

Yes, this is a new device that already complies with exiting standards which might make it viable for new research and development. Cool, go for it. But just because some people are switching to this new acoustic model to "test it, learn and figure out what to do with it" that doesn't make it the "new standard" yet

Also, we've recently been using the Brüel & Kjær Type 5128 head and torso simulator with HEAD acoustics' labCORE hardware and ACQUA test software, testing with HEAD acoustics' recently released MDAQS instrumental audio quality evaluation. From their description of MDAQS

Hopefully you guys will publish peer reviewed scientific papers using this device to contribute to the justification of a new standard.

Yet, it has to be seen that these new model has any practical/real-life benefits to make it a superior standard for the development of products, measurement and reference. The only selling point here it that it is more "accurate" according to the claim, but the data that you might provide with the 5128 has yet to be regarded as more meaningful for scientific research and development of quality of products. Because these are separate questions. You don't even have a target reference for reviewers to make any sense of what they measure. How is that supposed to be "the new standard"?. Simple things like reliability and reproducibility seem to be a big question marks with this device, for the sake of 'plankton-like' acoustics. That's not how it works when it comes to standards.

Even if you do the research to develop new references to make any sense of the data, you still have to prove that this is meaningfully superior than what we already have. So, is the investment on this kind of hardware worth it for most scientific institutions and companies to develop new products? It has yet to be seen. Nobody really knows. And you still don't know because you are still "testing and learning"

And hopefully these new push for the 5128 has less to do with infomercial activity than honest scientific curiosity.
 
Jun 29, 2023 at 5:27 PM Post #88 of 88
It's worrisome that vastly differing measurements of well-known headphones lead to corrective filters that don't sound at all alike. See the attached figure for the Sennheiser HD660S headphones. The top figure is from Tyll Herstens' InnerFidelity measurements; the middle one from the SonarWorks Reference 4 correction software, and the bottom one from the ToneBoosters MorphIt plug-in.

Obviously the filters constructed from the bottom 2 measurements will sound quite different.

For a fuller set of examples, see the 2nd attachment, which includes similar data for the Sennheiser HD660S, HiFiMan Sundara, AudioTechnica ATH-R70x and Oppo PM3 headphones.
 

Attachments

  • HD660S-measurements.jpg
    HD660S-measurements.jpg
    60.4 KB · Views: 0
  • TB-correction2.pdf
    693.6 KB · Views: 0

Users who are viewing this thread

Back
Top