[ricksome]

I like my set of Amperior's but I would like to add an open back headphone to my collection. Budget is under $200.00. Headphones should be easy to drive. Thanx / Rick

 

[KG Jag]

I'm not sure there is one.  Maybe the HD 518 comes closest.

 

[Southak]

I think Jag is right, there aren't many open back Sennhesier headphones that have the same punchy, rhythmic sound as the amperior. I have used the HD 650 with my laptop and the sound is not dissimilar but they cost over $400. At $200 the HD 558 or at $300 the HD 598 are the best open back headphones Sennhesier has to offer so either of those would be a great choice but I would recommend you listen to them first at your local dealer (if you can) as the sound is not the same - it is much more open and spacious.
 
It's worth noting that the HD 518, 558 & 598 are all rated at 50 ohms so not the easiest to drive. I have tried the HD 598 with my iPod Classic and it doesn't generate a huge amount of volume as mobile devices simply don't have the power. Also they are very open so sound leakage/lack of noise isolation may be a problem for you/those around you.

 

[viralcow]

Also, the amperiors have like, 0 soundstage. Opposite of a good open design.