Master Complaint Thread About Headphone Measurements

[thewas]

I don't know yet, but am positive after it's presented sooner or later we will find it and post it here.

 

[Robbo99999]

Sean Olive and Dan Clark are presenting at the AES Show 2025 Long Beach in October 25 a new headphone target curve defined for the B&K 5128 and GRAS45CA-10 test fixtures:

A Preferred Headphone Target Curve Defined for the B&K 5128 and GRAS45CA-10 Test Fixtures
Saturday October 25, 2025 3:30pm - 4:00pm PDT 103B

The Harman around-ear (AE) and on-ear (OE) headphone target specifies a preferred frequency response using a GRAS 45CA test fixture with the older RA045 ear simulator and a custom pinna designed by Welti (2015) to better match human headphone leakage effects. This target curve is often misapplied to measurements made on other test fixtures with different acoustic transfer impedances, leading to errors and misinterpretations. We measured 27 headphones on the original test fixture and two newer ones, the B&K 5128 and GRAS 45 CA-10. From these measurements, a correct target curve can be calculated to account for fixture differences, enabling more accurate assessments. To validate the method listening tests were conducted using two headphones with low and high acoustic impedances, measured and equalized on three fixtures using the same fixture-specific target to evaluate sound similarity.

AES Show 2025 Long Beach: A Preferred Headphone Target Curve Defin...

View more about this event at AES Show 2025 Long Beach

aesshow2025lb.sched.com

I happened upon the following post from Dan Clarke that alluded to this back in May, and he showed in a graph that he said was in alpha stages of deveopment of a Harman corverted curve for B&K 5128. He also said re the GRAS devices that the differences between the KB5000 ears that are used in current headphone measurements on GRAS differ to Sean Olive's modified ear he used for all the Harman work above 9kHz - so it looks like we'll be looking at changes to the GRAS curve above 9kHz for the most part, so we could consider these small changes given the frequency range, but we'll have to see in terms of the magnitude or if other areas of frequency response affected. So following is the Dan Clarke post that alluded to the alpha stage curve of Harman transferred to B&K 5128 with which he was working with Sean Olive:

D

Post in thread 'Dan Clark NOIRE XO Headphone Review'

May 9, 2025

Specifications

Weight: 408gr
Nominal Impedance: 13ohms
Distortion: <0.3% ref 94dB at 1KHz
Frequency Response: We do not publish this because no standard exists for what this actually means and far too many vendors simply publish absurd numbers in a spec game. We don't.


For the community, I have been working on a port of the Harman 2018 curve from the reference GRAS 45CA to the B&K 5128. The curve shown as the target was derived and verified using two independent processes, and with input from Sean Olive. This curve should be considered an Alpha target and not definitive but it is...

• Dan Clark

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