[darkfireblade25]

Sometimes I want to have these as a speaker since I don't have any for convenience. Do you think this is safe for the headphones? Will they wear down faster and shorten it's lifespan? Usually do it 30 min or so if I do use them like that.

 

[Head Injury]

Headphone drivers are very survivable. They're designed to play very loud.
 
That said you will wear them out faster if you play louder, because the drivers have to move farther. Each driver design is different, so I don't know if you could easily say that playing at X dB will last Y hours or anything. They last a long time at regular volume.

 

[idletime1213]

I'm sure a $50 speaker will sound better than listening far away from the HD598 at max volume.