Headphone and Headset Measurement Seminar

A couple of months ago, out of the clear blue, I was approached by the folks at Listen Inc. to see if I was interested in having an equipment sponsor for my headphone measurement program. After a few moments of stunned silence I said, "Um, sure, let's talk about it."

Now I love my Audio Precision SYS2522 System 2 Cascade tester, but it's very long in the tooth at this point. For instance, it uses a special interface that requires a computer with an AT motherboard—very old school and difficult to maintain. I have to keep a spare old computer as a backup in case my main measuring computer fails. This puts some limits on the software I can use—mainly I have to keep a very old copy of Excel up and running for dumping data into spreadsheets.

A more pressing problem is the version of software I need to program the AP requires quite a bit of Basic programming...and I'm no programmer. It's very difficult for me to write new scripts. But more important is that I'm very limited in my testing of Bluetooth, USB, and Lightning connected headphones.

Both AP and Listen now have gear that can circumvent these problems. But Listen has a strong focus on acoustic testing, and headphone and headset testing in particular. They also have some killer software that makes creating test sequences surprisingly easy. Listen Inc. rolled out the red carpet for me and are willing to pitch in to help me get my system up to speed. How could I refuse?

Well, lots of things to consider in switching over systems: Will it deliver the same measurements? Can it format the data exactly the same as my current spreadsheets? What kind of additional data can I acquire? Some serious face time was in order.

As luck would have it, Listen Inc. and G.R.A.S. were holding some headphone measurement seminars and they invited me out for the seminar, and to talk for a bit the next day about my needs in particular. Off to Boston I went.

The headphone measurement seminar had three presenters: Steve Temme, President, and Daniel Knighten, Sales and Applications Engineer, gave us the rundown of how to configure Listen Inc. gear for headphone measurements. Peter Wulf-Anderson, Director & Owner, presented a detailed exploration of the new G.R.A.S. high resolution ear simulator and anthropometric pinna and ear canal. And Sean Olive, Acoustic Research Fellow at Harman International, provided a detailed overview of the last five years research developing a headphone target response curve.

I'll be providing updates in future on the Listen Inc. gear to be used for the InnerFidelity headphone measurement program, but figured you might enjoy some tasty info from the presentations given. I'll only manage to skim the surface here as the presentations were dense with information. Listen Inc. has kindly allowed InnerFidelity readers access to the presentation .pdfs after logging into their site through this link.

COMMENTS
jim in cheyenne's picture

This is great news! Yeah it's time to update the equipment.

How to bridge between the old measurements and the new? You will have better ideas than I, but I would think a half dozen or so well chosen headphones, from modest to 'all-out' with carful discussion of the differences would suffice. Of couse all of us hope than half dozen includes our favorite....

Good luck, keep up the good work!

jim in cheyenne's picture

This is great news! Yeah it's time to update the equipment.

How to bridge between the old measurements and the new? You will have better ideas than I, but I would think a half dozen or so well chosen headphones, from modest to 'all-out' with carful discussion of the differences would suffice. Of couse all of us hope than half dozen includes our favorite....

Good luck, keep up the good work!

Oops, I tried to register, but Listen wouln'd accept it
Is ther some 'company' we are supposed to use?

JMB's picture

I quite appreciate the progress in Grass design. Our ear canals and pinnae are quite variable (even between one owns left and right ones) so exactly which would be the one to choose? Also the materials used to make artificial ears/heads are quite different to our tissues (especially regarding damping and resonance behavior). So there will be an ever changing improvement for more realistic ears (upgrade for ever like we do our toys).
I still have a more basic question about how measurements at the eardrum are relevant for headphones but not for loudspeakers. I understand that IEMs don not use our outer ear and only a part of the ear canal but that does not apply to circumaural headphones which leave the function of the ear canal and at least partially the outer ear intact as would listening to loudspeaker in free air. Basically this is a question about what is the right compensation curve.

coastman25's picture

Surely, the obvious candidates for revaluation using the new testing methods and equipment would be your current wall of fame headphones. However before going there perhaps look at models were the test results did not match your listening experience and see if that is still the case with the Listen Inc system. Then some visa a versa ie re-test some you are familiar with I know for sure your listening experience matches your current test results.

GTABC's picture

That would make the most sense to start.

I'm really interested in the subjectively poor headphones with good measurements(under the old methodology) along with subjectively good headphones with bad measurements (under the old methodology).

Gosh it would be nice if new measurement equipment/ techniques changed measurements in such a way that they would more often be aligned with subjective impressions.

I've often heard that headphones that measure poorly rarely sound good but that there are many examples of headphones that measure well but sound awful.

100VoltTube's picture

I would also love to see some more measurements of those types of headphones. In addition, it might also be interesting to see more measurements of headphones where the measurements tell one story about the sound signature and the listening tells a different one. For example, the beyer T70

100VoltTube's picture

It might be interesting to look at Fourier transforms of the headphones' output as a function of input frequency. A sort of 3D Fourier transform, if you will (or just a couple of normal Fourier plots). It might also be interesting to see how the distortion components change during the decay of a tone. Like a CSD plot, but the decay of a single sine wave.

Journeyman's picture

I do hope they help you out. It's great advertising in the long run given the fact you are a reference for many headphone enthusiasts.
I also think the headphone community would be very grateful.
Tyll I do hope you measure some Beyerdynamic Headphones models again. :-D I know you don't really like them but the DT880 is a reference for many people.

MRC01's picture

What a treat. It's great to see this level of research which will improve SOTA for everyone. Thanks for sharing the experience. As for what kind of new measurements to include, I suggest CSD plots.

zobel's picture

I imagine that the new distortion / noise measurements may be the biggest improvement in conveying perceived sound quality. Those, along with the waterfall plot, and improved SPL/freq. graph, there has to be be a much improved set of measurements that will go much further in describing the sonic features of all HP measured.

Thanks for keeping your tests as relevant as possible Tyll. I like your idea of covering the 'worthy' cans and letting the unwashed hoard go as is.

thu hien's picture
bobusn's picture

No excuses! Thanks for your dedication, Tyll!

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