RTINGS study on distortion audibility in headphones and IEMs

[PierreRtings]

@PierreRtings . From the test: "Using binaural recording, we captured everything the headphones produced: both linear (frequency-response-related ) and nonlinear distortions. Then we removed the frequency response, leaving only nonlinear distortion and level differences between headphones. After this, we normalized all these recordings at -16 LUFS , so that listeners heard distortion, not frequency response or level differences".

What target did you use for the frequency response correction? An average between all headphones, flat, or the target response you normally use? The reason I ask is that some of the headphones, like the HD650, have a weak bass response and could maybe show noticeable distortion at lower SPL when you eq them towards the target response. (And you would of course need to use some bass heavy music to notice). Just trying to understand if the test already covers this aspect.

View attachment 509609
(Source https://www.rtings.com/headphones/reviews/sennheiser/hd-650).

I guess "flat" would be the correct answer but this term is ambiguous. When we say "removing the frequency response" It means, the equalization curve, is the reciprocal of the frequency response of the headphone. Effectively, whatever magnitude variation that is measured at the HATS eardrum, that includes the response of the headphone, but also the HRTF of the test fixture, is inverted.

 

[Head_Unit]

I'm the dot at the end at 51....

Well, better to be an outlier than dead!
As I read and re-read, I'm getting an implication that if the frequency response is equalized out, the headphones are indistinguishable?* Is that correct?
*except maybe the ZERO: RED somewhat.

 

[PierreRtings]

Well, better to be an outlier than dead!
As I read and re-read, I'm getting an implication that if the frequency response is equalized out, the headphones are indistinguishable?* Is that correct?
*except maybe the ZERO: RED somewhat.

I always stay extra careful on strong conclusions like that, but within the scope of our study, Our listeners where not able to distinguish between headphones that's correct.