In reply to lone:
In my experience, loud blowouts are generally down to either a hole in the tyre or something major like that allowing the inner tube to touch the road (a similarly major issue on the inside of your wheel might have the same effect), or where the inner tube gets pinched between the tyre and the rim. If you can't see anything to obviously puncture the inner tube, I doubt it would be major enough to cause a loud blowout, usually smaller stuff causes a quieter puncture.
If the tyre isn't that worn and you're really sure there's nothing obvious in it (worth looking round the outside as well as the inside and pinch any small splits or holes to see if there's any broken glass or thorns in there) then I would get a new inner tube and take extra care that it isn't pinched between the tyre and the rim. I normally put a little bit of air in and then go around each side of the tyre pushing it away from the rim to check that I can't see the inner tube.