[dynamo61]

The guy at at Roger’s in Liberty, Mo. last week when I went there to test them side by side didn’t have a meter but to both his & my ears(with my HA’s in ) couldn’t tell the difference in sound between the FL & 505 with the high end TP arrows for each(16” & 20” lengths).

There is a Sound Meter app available for most smart phones.
Works very well, just FYI.