The HD650 has a mid bass "hump", so there is bass emphasis and is why it sounds bassier than the HD600. What it doesn't have is any sub-bass as it rolls off sharply from 50~60Hz, which is one of the differences between it and the HE400i, which carries on down to 20Hz or so, something that planars excel at.
The Hd650 has some of the best mids you'll find outside of TOTL offerings from the £1k+ sector. The HE400i isn't far behind though, it too has excellent mids, they are just not as lush and rich as the Sennheisers.
The high frequencies pose something of a split in opinions, there is plenty of detail there, it's just that they are rolled off compared with the mids, which is where the (erroneous) veil description comes from. If you are used to listening to headphones that have hot highs, like the AKG K702 or Beyerdynamic DT 770, 880 or 990 (or Teslas) then yes, the HD650 will sound somewhat dull and muffled to start with BUT after listening for an hour or two, this "veil" will lift and you'll discover all that detail was there all the time. The HE400i on the other hand has much airier and more detailed highs which provide very accurate imaging, which is somewhere the the HD650s fall down, they tend to have focal "blobs" and instruments / voices will be central, left or right while the HE400i (and specially the HE560i) have imaging that lets you visualise the exact positions of the instruments.
One word of caution, you mention that you want to use them in bed, while your wife is sleeping - wouldn't closed back headphones be better? The HD650 isolates poorly, being open backed and the HE400i is more like a pair of speakers strapped to your head and can be heard easily from 15 plus feet away.