Auditioned a pair sig pros today, courtesy of audioaffair in birmingham (uk).  I was  impressed with them , so now i'm an owner of a pair..  this thread has proved invaluable in pointing up the strengths and weaknesses of these.  I'm happy with them, taking into account they are closed ( which...

I think so, when I was looking for a portable amp to go with these it was the E7 versus E17. from what i read and have experienced the E17 gives a noticable difference, at least to my ears.  

I use an E17 with mine and that seems to improve the bass response. On the headband, i find if i gently pull down when wearing these the seal improves and the headband adjusts so its not as noticeable  

hi all   i have had a pair of AKG 550 for about 6 weeks.  I find them comfortable, good isolation and have the sound signature I like.   Not much to add to the comments already made in this informative thread, only I have noticed with large orchestral works  e.g beethoven symphonies they do...