Yamaha DTXpress/DTXplorer/DTXtreme

Alright, I have one complaint on my Yamaha headphones, when I play, 
I am getting ocassional static sound...almost like they are on 
overload.  I am running these thru a mixer.  I am beginning to 
wonder if these phones are the best investment for my DTX.
I am wondering...what do you experienced guys recommend?  I would 
LOVE to get the Sennheiser HD-25, but, dio I really need to spend a 
few hundred on these?  Can somebody help with any suggestions.  Do I 
need REAL studio quality phones like the HD-25? or can I get by with 
Sony MDR7506 or the Sennheiser HD-270.  Right now I am using Yamaha 
RH-5MAs, but they distort on the real low bass drum settings.  Any 
help will be appreciated.
Jade