D'abord du nouveau matériel, l'Irig mic:
http://www.ikmultimedia.com/irigmic/features/
comme on peut le constater, le micro est bien brancher sur la prise jack, alors pourquoi mon micro ne fonctionne pas de la même façon?  

Yes, we have this adapter which will allow your mic to connect to the iPhone:
http://www.kvconnection.com/product-p/km-iphone-mic.htm
The iPhone only has a mono mic input so although the mic will work, it will only do mono and not the stereo. 

Line/Mic Inputs:
One 1/8" (3.5mm) stereo unbalanced input
Selectable pad
Continuously variable gain
Specifications:
Minimum input impedance: 4.7kohm
Maximum input level (pad on, line-input): 6.5Vrms (+18dBu)
Minimum input level (boost on, full scale mic): 7.5mVrms (-40dBu)
Frequency response (40Hz to 20kHz): +0.06/-0.65dB
Noise level (RMS, A-weighted): -88dB
Dynamic range (RMS, A-weighted): 88dB
THD (-3dBFS): 0.05% (-66dB)
Stereo crosstalk (1kHz): -86dB 

What makes GuitarJack better than other iOS guitar input accessories?
When compared with guitar input adapters that connect via the headset input, GuitarJack has the least amount of crosstalk. The headset input inherently has a lot of crosstalk (noticeable with recording and input-monitoring), and the only way to have access to access to communicate with software (necessary for stereo recording and more) is via the dock connector. GuitarJack offers the quieter and software-controllable dock connector route.

GuitarJack is better than alternative dock connecting, device-powered accessories that may be coming available because it is the only accessory that offers stereo recording and simultaneous voice and instrument recording with apps like FourTrack; a 1/4 inch instrument input with configurable pad, Lo-Z and Hi-Z modes and 60dB of continuous level control; a 1/8 inch stereo mic/line input with configurable pad and 60dB of continuous level control; and an 1/8 inch stereo output with increased drive for headphones.