Amir measures at levels others never do. Most headphones will be in trouble but at 114dB SPL. In the lowest bass less than 10% is not really audible at these listening levels.
When one is reaching 114dB at around 5kHz (even peaks in music) the bass would already be closer to 130dB or so. One wouldn't want to have this headphone on your head at these levels when upper mids reach those levels.
Bass levels... sure, certainly with a lot of bass boost that would be enjoyable (for the duration of a song) with 114dB bass boost.
It looks weird and poor quality at 114dB but in reality is looking at levels most will never ever reach (those that value their hearing).
Amir provides a measurement point others don't with the 114dB. Personally I look at the plot of 114dB and then disregard anything that happens above 100Hz and look at the 104 and 94dB traces to get an idea of distortion in the mids (where hearing is most sensitive).
A pinna probably does alter distortion at mid-high frequencies somewhat Can't say how much a few dB probably at most.
I use a $ 0.60 microphone capsule with a fixed gain home made mic pre-amp and nowhere near AP quality distortion levels ADC (EMU 0402)
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Above 95dB the measurement chain distortion becomes a thing and at just above 100dB becomes too high so alas cannot measure higher.