[DefBringer]

Here's my setup and results with Destiny and using PS4 Party Chat:
 
1. MixAmp Pro + Astro A40:  OK audio, microphone sounds "like I am using a walkie talkie"
 
2. MixAmp Pro + Sennheiser G4ME One's. Using a 3.5mm splitter.  Audio is fantastic, microphone: "Sounds like I am shouting in a megaphone, heavy echo"
 
3. Eliminating MixAmp Pro from equation, plugging in G4ME headphones w/ splitter directly into PS4 controller: Mic sounds PERFECT, audio is flat...not enough amplification.
 
 
Configuration: I have done everything in the PS4 audio and device settings that I can possibly think of.
 
I am beyond frustrated. My friends in Destiny are all using Sony Gold's, they sound pretty clear to me but I have tried those headphones and they sound like trash to me. 

How do you guys use quality headphones with your MixAmp Pro while not suffering from the crap mic quality issue?

 

[NA Blur]

Give this HowTo vid a try and report back:
 
https://www.youtube.com/watch?v=Tm_9iz2GnVg

 

[ThatSlimJoeKim]

I had this same issue and it was a headphone/mic jack issue.  I returned it for a new A40 and got a good headset.  Did you try putting the mic into the other side?