Hi, I have the possibility to buy a pair of Akg C 391 B or two AT4051. Both quite the same price (around 400€), the AT4051 slightly cheaper. One question: are they both true condensor mics, i.e. no electret? Adv of the akg: - easier to change capsule, there is even a bi-directional one that i could need Dis of the akg: - they come without windschield and clams adv of the at4051: - they could sound better, according to many reviews I read - they are a bit cheaper - they come with a box and everything - they should be a bit more sensitive than the akg dis of the At4051: - it's not so easy to change capsule (not many used). there is no bi-directional capsule My main uses are: field recording (low level sound), different kind of sounds; sometimes instruments (horn, piano, sax). What would you suggest me?