From a macbook, the odds are small, i dont think it can go loud enough on a laptop to cause a problem. However, I would worry about the adapter needed to fit into the 1/8 jack on your laptop. The hd598 comes with a large 1/4 cable and you need to use the 1/8th adapter that comes with the set to be used on normal audio jacks. It ends up being extremely long and heavy and could cause damage to your fragile audio jack on your laptop
If you are on the go, I wouldnt recommend the hd598 or anything open. If its to be used at home or something, then sure thats fine. Otherwise you look like a radar dish and leak sound to everyone
it really does not simulate surround sound, this is absolute nonense if anyone says otherwise. No head set that I am aware of can produce sound behind you, real 5.1 and 7.1 speakers are set up with one behind you so you get that effect.
However, the 598 stage is very large and spacious, very fun and great for movies and gaming.
hope you enjoy them, I love mine. Just bought an AKG K450 replacement cable in hopes of it fitting on the hd598 so i could sit outside without lugging a giant 10ft cable around, seems like the k450 replacement cable is identical to the stock 598 cable with that odd extended 2.5mm locking adapter on one end, and the other is a 3.5mm so i dont have to worry about using yet another adapter just to use on an mp3 player hehe.
*crosses fingers.
Also, about amping needs. The HD598 sounds very good out of my sansa fuze, but the difference from just the fuze to a portable amp like my E11 is very noticeable, bigger stage, smoother bass, more tonal. And the difference from the e11 to my E9 is yet larger, the stage is noticeably more deep and textured, the stage is definitely wider and separation is significantly better than just using an mp3 player. Cant say how your laptop sounds without an amp, but know that an e11 is like 65 bucks and sounds great, and its very small.