Front speakers make clapping noise

i got a 93 and the front speakers only fit 4in, so i go out and i get some VDO 4in 100w thinking that there good, well thats wat the lady told me but when i crank them up it sounds like they the speaker is hitting agiant the tweeter to something. It is because i only have 2 holes ot mount the speaker in, instead of 4, does any one have a good front speaker set up. i cant fit 6in in coz of the existing monuts. can i custom build some, rip some off some other car. what to do

Maybe it is hitting against something .Dismount them and see what they sound like.If they still sound bad take them back.