Hah! I’ve done the same a couple of times before…though granted this was before the Sundara had a pad update which significantly changed the sound. I did get to hear the Susvara and HE1000 at the time..but with no real reference point. I’ve later learned that I get far more out of any audition if I remember to bring along a headphone of my own. Can be a very sobering experience actually and often irritate the seller immensely.
The Avantone is laidback in both the uppermids and treble like 98% of all other planars on the market, although not nearly as severe as the old Audezes. I think that is what generally keeps planars from achieving the right timbre…except for the Sundara and LCD-5 of course
There will always be a big difference between the 600 and a properly made planar magnetic. The 600 comes with a small mid-high bass bump and planars don’t really do that unless you close off the cups a la DCA’s Aeon Flow “Open”. The small bass bump on the 600, coupled together with the distortion down low, makes for a very characteristic sound profile that planars can’t replicate (and properly shouldn’t). Then again..the totally flat bass of planars also gives us detail and extension beyond anything found in dynamic driver headphones.
Each design has it’s own merits and flaws. I love both. Today I’m in a 600 mood though