blown sub ? please help

My question is can an enclosure affect a sub performance so much that it can change its power handling capabilities.  My friend has 2 15s inside a really small box with no divider.  His magnet is about 1 inch from the back wall of the box.  He keeps blowing his subs and i want to know if the box can have something to do with it.  All his connections are fine amp wasnt turned up high and the max on his subs were 1000 watts. his amp was only 800 watts also.  so could the enclosure be a possible reason i know it may be alot of other possibilities but the connection were fine wired up in series.

Can not having a divider cause sub to have big problems like blowing them.

not having a divider won't cause them to blow, unless you don't have the right size box

list what make and model subs you have and how big the box is, e.x volume size 1 cubic ft

cuz if you have to big of a box then it could have caused one to blow so won't know untill you tell me the specs on what you have and maybe just cuz you have to much power going to them

the subs are 500 watts rms 1000 watts peak kicker CRV `15's

It isn't mandatory on your box having a divider but as tdsteele said it depends on multiple variables. Box size, speaker requirements, and also the way the subs are wired.

The type of amp and settings of the gain on the amp compared to the radio is also something to look at. The amp gains may be down but if your friend is turning the radio up louder to compensate he is creating distortion which will also blow the subs.

The amount of room between the magnet and box walls is not important in all situations but in this app. it seems not to be the issue. With a sealed box the only issue that is really prevailing is the total amount of airspace.