Your Xbox 360 keeps cutting you out when you are talking in parties

For some reason, whenever I am in xbox live parties, i randomally stop transmitting my voice. It isn't my mic; I have three mics and have tried all of them. The same results. I also have four controllers and have tried three of them. No changes. However, whenever I am in game chat or private chat, it doesn't cut me out. I recently got an xbox elite, so that might have something to do with it, but it was fine for the first week I had it. If anyone knows what the problem is or how to fix it, plz tell me.