If your Dyson vacuum gets very loud, it's time to address the cause of the noise. Look for blockages first and then get help from Dyson, if necessary. Performing repairs or disassembling a Dyson to the point that you expose internal components yourself may void your warranty, so don't undertake these tasks. If you hear loud noises, it may indicate a more serious issue, one you want to clear up immediately so as not to possibly damage your Dyson vacuum permanently.
Turn off the vacuum and unplug its power cord from the wall.
Unhook the hose and remove any attachments. Look inside the hose and remove any blockages.
Look inside all of the tools for blockages and remove, if needed.
Lay the cleaner down and look inside it where the brush bar sits. If you see any blockages, remove them.
Press the filter release button on the cleaner head to remove the filter. Look inside the any openings under the filter for blockages.
Plug the vacuum back in and turn it on after you clear any blockages. If the noise continues, contact Dyson for assistance.