"Dave" wrote in message
...
Yes... it can be REALLY irritating..

I have a twin engine boat, same issue... VERY annoying.. to me, and
many others..

Some don't seem to mind.. (?)

Not only the noise, but the vibrations , when out of sync, can be very
annoying as well...

Dave

We had a Cessna 337 on our line for charter use at one time. It had a sync
gauge. Strangely enough, whenever I had occasion to fly this bird I always
ended up syncing the props by ear. You could easily feel if one of them was
out even by a small amount of RPM.
Dudley Henriques