The biggest theoretical "weakness" of a push-pull design, to my understanding, is that the magnet assembly creates a cavity that can cause resonance issues. It also creates a barrier between the membrane and the ear. Something like the Audez'e Fazor is designed to correct this, while a single sided planar avoids it by design.
That is true, the question maybe what's more sound degrading/audible ... issues with the 'blockage' between the membrane and ear abd or wavefront issues or linearity ?
The HE1000 has a more open structure and a magnetic field,
It may be a better compromise than the small holes of a symmetric driver or the non-linearity of the single magnet driver.
Dunno.... the aswer.
The fazor only 'solves' the wavefront problem at certain parts of the frequency band though.
The blockage and relative small holes are still there and so are the cavities.
I never heard most of these models (only a few of them) so really can't say much about it sonically in a general sense.
What is considered the best sounding HE ?
Does this have the lowest distortion and is symmetrical or is it the HE560 ?
Acc to Tyll's plots the THD of the HE-6 is about the same (in average value) but the HE560 isn't as 'constant'. (100dB SPL)
Perhaps the excursions of the membrane are relatively small compared to the membrane stator distance and non-linearity isn't a practical issue that much. (just guessing)
Anyway, Perhaps the next 'driver type' has small magnets on both sides of the driver, more open and symmetrical but lower efficiency perhaps and a higher pricetag yet again.
