While in service I had the displeasure of flying in the back end of a TBM from NAS Corpus Christi, Texas to NAS Columbus, Ohio. I use the term displeasure because I had no ear protection and my body was exposed to some severe and continuous vibration. I put 1400 hours as a flight engineer sitting between and slightly behind two R-1830-92s and the noise generated by those two engines was not as loud as the noise coming from the front end of the TBM.