Which Qs to choose: questions of quality in Bioacoustics?

Two Q factors are in common use in bioacoustics: Q, the Quality Factor and Q_10dB. The usage, definitions and separate application of these two terms can be traced back for more than 30 years. The two terms provide different measurements of the sharpness of tuning of e.g. acoustic systems. The two terms have been used in separate contexts and they measure different things. In view of the confusion that arises from the shared use of the letter Q, it is important that whichever Q is used is defined clearly in all publications.