EQ'ing that bass in is effortless. Got a 4.4mm cable for them with a nice braid.
I do gaming with them and it just feels so freaking wide.
I'm a percussion guy. Drums and intricate percussive ellements, in music, sound blissful.
Try listening to Dinossaur - OTR Remix, close your eyes and have fun.
It depends a lot on how loud you listen and whether you want to EQ. Sundara is very well tuned and doesn't really need much EQ, a small bass boost at most.
Sensitivity on the Sundara is 94db/mW, that means you get 94dB out of 1mW of power. The US version of the Apple dongle will do its full 1V into 32Ω without clipping, which is 31mW.
If I'm listening to it without EQ, about 1mW is a comfortable listening level, 2mW is loud and about as high as I'd go (Qudelix reports exact voltage/power).
The EQ I use with them, if I do, has a -3dB negative pre-amp, so putting that back would be a further doubling of the power to 4mW... it's still not a whole lot.
The HE400SE is harder again at 91dB/mW though and in measurements even a bit lower. So it needs twice the power of the Sundara for the same volume level.
I'd never suggest the Apple dongle for these (or for that matter the Sundara). But if someone has the Apple dongle already, it's worth trying. It does depend how loud you listen.