New YouTube series with Axel Grell: The history of target curves

[totti1965]

Axel Grell, the living legend, the inventor of the Sennheiser HD 580 / HD 600 in 1990, the benchmark against which all headphones are still measured today, has his own YouTube channel now.
In this video he speaks about the development of target curves.
From the very first beginnings with Alexander Graham Bell,
to the first half of the 20th century with technical limitations to the range from 300 Hz to 3.400 Hz
to the 60s and 70s when HiFi stereo gets bigger.
He makes clear, what the difference between freefield and diffusefield is.
He pointed out that for studio purposes the diffusefield curve often is better, because of the
Acoustical lense usecase of Headphones in studios (E.g. AKG DF 240, Beyerdynamic DT 770)
And he says something about the necesserety to go something in between diffusefield and freefield.
Also it’s the first time, that I see a proper explanation for the 8 kHz dip in freefield fitting.
All in all: Very interesting stuff.

Next time they spoke about loudness and the Harman curve!

 

[markanini]

He pointed out that for studio purposes the diffusefield curve often is better, because of the
Acoustical lense usecase of Headphones in studios (E.g. AKG DF 240, Beyerdynamic DT 770)

I assume he doesn't mean tuning to a literal DF target but a modified one, something closer to Harman 2018 target but 2-4dB less bass. An R&D phase would have to veto out anything as bright tilted as unaltered DF. Unless corners were cut on R&D, or acoustic profile was not prioritized.

And he says something about the necesserety to go something in between diffusefield and freefield.

Reinforces Sean Olive implicitly given the use of the Harman listening room, that has a mix of reflective absorbing surfaces, as a basis for the HRTF component in Harman 2013, 2015, and 2018.

 

[Jermo]

Axel Grell, the living legend, the inventor of the Sennheiser HD 580 / HD 600 in 1990, the benchmark against which all headphones are still measured today, has his own YouTube channel now.
In this video he speaks about the development of target curves.
From the very first beginnings with Alexander Graham Bell,
to the first half of the 20th century with technical limitations to the range from 300 Hz to 3.400 Hz
to the 60s and 70s when HiFi stereo gets bigger.
He makes clear, what the difference between freefield and diffusefield is.
He pointed out that for studio purposes the diffusefield curve often is better, because of the
Acoustical lense usecase of Headphones in studios (E.g. AKG DF 240, Beyerdynamic DT 770)
And he says something about the necesserety to go something in between diffusefield and freefield.
Also it’s the first time, that I see a proper explanation for the 8 kHz dip in freefield fitting.
All in all: Very interesting stuff.

Next time they spoke about loudness and the Harman curve!

Hi Thorsten, thanks for sharing!
The purpose of the video is mostly historical education. We don't have many free field-tuned headphones around, but the pure diffuse field has worked very well for professionals to detect "inaudible" sound artifacts from editing. That is why we still see so many of the classic Beyerdynamic headphones around, which have been excellently engineered to meet that goal. Our conclusion is that neither target is great for music enjoyment, and the implicit explanation for that is that they have been created with only measurement devices, without considering the element of human perception. I'm editing the video for that topic right now

 

[totti1965]

We are waiting eagerly......
Thanks for this great educational series!

thorsten

 

[JSmith]

I'm editing the video for that topic right now

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JSmith

 

[Jermo]

Hello and welcome to ASR.

It seems you are a reviewer (@amirm), so please read and follow this;

Rules for Audio Dealers, Manufacturers, Members with Commercial Interest. This includes any Guest Contributors/Reviewer with Commercial endorsement

Audio Science Review Rules for Dealers, Manufacturers, Reviewers and Members of Industry. We encourage participation from members of industry in the forum. So please feel welcome here. We expect you to post with highest levels of professionalism. You are representing an industry and it is...

www.audiosciencereview.com

JSmith

Thanks for the warm welcome and the heads-up