my K340 is an hybrid with two dedicated cells and with an internal grid of 5 Helmholtz tuned resonators separating perfectly among other effects bass and mids and making this phone to give deep bass without flowing interaction with usual bass..
Not only that but i modified and optimized them with 6 mods... The main one is i put inside and outside anti resonance materials and dampers of two kind to comnplement each others ...
By bone resonances i feel deep bass with my chest and feet...
is it 20 hertz ?
i did not measure it but i listen big church organ music of Bach and some organ go down 8 hertz...
I am pretty sure i hear then 20 hertz or near it with my feet ...
I disliked all headphones i bough... Save the K340 i like a lot after 6 months of intensive studies about it even with the original paper of the founder of AKG who design it...
I spoke with Kennerton representant about hybrid headphones as the K340... Because i asked them how they will build one...
They said it is too costly to design right because of the research implkied, too costly to make and too litlle profit...
This design complexities is the reason it takes me time to improve them so much that they are my audiophile reference now not my small modified speakers so much i love them ..
By the way if the recording make it possible i hear the soundfield out of my head...Not inside my head...
My best to you my friend ...
@mahgister 20hz in your ’phones?