Now the bad news :'(
Look at this!!
Guess how we did this damage.
Tested 20Hz in the dB drag position & rules - doors and windows closed.
149.8dB

Just need some pushing on the doors an this score should go up.
This was fine.
Then decided to try & find my peak SPL.
1st Burp @ 32Hz and there was a bit of tone then a slapping sound at which point the sub was mullered
Only hit 153.3dB
Now this is the 2nd sub, in a low tuned system, to be destroyed by playing with the doors & windows sealed.
So I`ve come to the conclusion that:
WARNING!! LOW TUNED SYSTEMS don`t like to play at full whack with sealed cabins.
I`ve never had any problems with this until we tested with the doors & windows closed.
Is it possible to get a Re-Cone kit or something?
PM sent to Nick