Bass Resonances in Club's stage

I'm working in student Club like sound man. Stage that we have is improvised with school desks, couse we are nonprofit Club and don't have money for doing real one. So, it seems that this big stage (made by desks), dimensions of 5m x 3m, produce unpleasent bass resonances. I wonder.. if i put some acoustic hangars, under desks, can i kill those bass resonances, should i make hangers of different sizes, like 1m x 0,5m.. 2m x 0,5m or so... p.s. sorry for my english... if i said something wrong..

Hi gogi - your english is fine :) Are te resonances caused by the stage vibrating?? cheers John

yes, i suppose.. the wood is very thin, all instruments are on this part of stage, bass amplifier too, but i'm sure that stage takes most of bass from room (sub bass F.O.H is about 2 x 1200 W), so very much bass in room, how can i construct bass traps for this large space, shape of room is let say 15m x 10m x 6m, room is very high (it has gallery).. p.s. i will try to take some photo, and draw floor plan

I suggest first trying to reinforce the under sides of the desks with wood or metal beams. This will kill the bass resonances before they even occur and be much more effective than trying to absorb the sound afterwards. Thomas