Only made very careful if you use this product for a Canon 7D.
Indeed some DSLR (7d in my case) is a sound management system automatically "AGC".
If you can not disable your microphone ... can not do anything better than what there is already at the start ...
Think therefore is: be sure that your device does not have an MCO or you can disable
and then buy an external product (type: Juicedlink DS214) that disables the AGC and in addition offers a sound return ...
Good buy !!!!