cabinet sound trouble

Well, there is some kind of problem with a sound in my cab.
It sounds like crap! when I do a sound check I hear a sound coming out of a right speaker and a left speaker, everything is sounds fine, but when I play games, this is just unbearable, I have to really turn it down. It is hard to explain what it sounds like, but I will try, the music part sounds fine, but when it get to sound f/x, shots, punches, kicks - it kind of sounds out of context, to loud and crazy,somewhat flat, it is really hurting my ears.
I tried this cab with my hyper 64 and it was good, more or less like it should be full bodied sound and such.
Now, should I upgrade my speakers ? Is there something going on with my 4-slot that I'm not aware of, like it switched to mono ?
I have no idea how to check, even after reading this forum.
Any help will be appreciated.
Regards,
JL

What Cab is it..?..Type..

What Hyper 64 board did you try..REV 1 or 2 board.?
REV 1 requires all the extra speaker and power wiring-harness to work.
I don't think you'd get any sound without that,with a stereo set-up.
....
You may need to give your carts a good contact cleaning..

http://www.hardmvs.com/

Do you hear the sound coming from the right and left speaker..separately?..
Or do you hear sound coming from both no matter what side you choose.?

if the speakers are wired like this, it may work

yeah,
I hear sounds separetly if I go through a sound test.
I will try to give my carts some cleaning tomorrow,
I'm not sure if will help much,
what are the chances that all of mine carts will be that dirty to
make it sound like that.
I think the case most likely that 4-slot is set in mono and jamma is wired for stereo. Is it possible ? Can this be a case ?
BTW I have super neo 29 cab with 4 slot in it.
I tested revision2 in it.