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:
- 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).