I use bass shakers in addition to my subwoofer. The shakers have their own amp but connect to the pc through the center/sub channel. My audio card is Auzen X-Fi Forte 7.1, which has the normal channels same as other cards.

My problem is mainly with flying sim program FB IL-2. The shakers work great but only when you are looking in the forward position and about 40 degrees spread in that area. When you look in a different direction vibration of
the aircraft leaves you, you do not lose the sound but you do lose the feeling you should be getting from the shakers, pretty much 360 degrees,engine vib.

I am sure it is because the shakers are tied in through the center/sub channel. I tried have many ways but cannot figure how to route the shakers so I can have the vibration of the engine 360 deg.

There may not be a way that this can be done but appreciate any suggestions.

Thanks
Dale

Like you suggested, I think it may be because it's linked to the centre channel. Maybe try attaching it to the L and R channels through a splitter?