After hours of looking on google, I found a modification that helps 10x better the audio output of this microphone with vertex radios, it consist on removing one resistor and adding a small capacitor, I tested the modification and WOW, super clear audio with deep tone, while putting everything together by mistake I damaged a second resistor and somehow it sounded even better, super loud, just like those nice amplified microphones.
Tomorrow I'm receiving a new microphone and I will take pictures on how to make the modification and a video of before and after. I'm pretty sure this will help a lot of people, since I read reviews of people buying this radios and the audio is low, but the problem is the microphone, the MH-25A8J is different than the MH-67A8j, the MH-68A8J works great on ham radios where you can raise the gain of the microphone, but on this radio you only have Standard Mic Sensitivity or Low.