Sennheiser Game Zero Special Edition audio quality terrible.

[thunderbolta7]

First time on a thread so here goes nothing.... I bought the Game Zero SE headset as part of my Christmas this year as well as the sennheizer mic/speaker joining adapter. I plugged them into my iPhone 6 and the sound was absolutely abizmal! The vocal sounds as if it were coming through a mile long tunnel and the instruments were extremely quiet. I cranked the volume to max and it still wasn't hurting my ears at all (If I did this on my old turtle beaches it would hurt to me anyway) Even better yet the bass seems to be completely missing. Just to make sure this is clear the bass isn't "weak" it is nonexistent like the speakers aren't triggered at all to play that line of audio. I have tried these headsets out on my laptop and on my phone (Asus G551 and IPhone 6 respectively) and with and without the adapter.

Any ideas on what the issue is or did I just get the unlucky dud and need to return the headset? Thank you in advance!

Link to headset:
Sennheiser GAME ZERO Special Edition Gaming Headset https/www.amazon.com/dp/B0711SG5V6/ref=cm_sw_r_cp_api_5i2qAbEB6VTPN

PDF from Sennheizer on the headset:
https/en-us.sennheiser.com/global-downloads/file/9434/Fact_sheet_-_GAME_ZERO_Special_Edition.pdf

Link to splitter:
Sennheiser PCV 05 Combo Audio Adapter https/www.amazon.com/dp/B00IM36VU0/ref=cm_sw_r_cp_api_Vj2qAb37TDCBP

 

[popatim]

Don't those heasesets need an amplifier to sound right? I think they do.