Quantz makes clear (ch. 17, sec. 7.9, p. 244) that ensemble players should follow these principles even though the keyboard is tuned to some kind of good (presumably irregular) temperament (gute Temperatur). Since he cites Db, G# and A# among the problematic notes on the keyboard, it is certain at any rate that he is not talking about Equal Temperament. Quantz makes clear that while the ensemble players should put the notes in their proper ratios according to the notation, it is the keyboard player’s responsibility to “bury” the keyboard’s offending notes lower in the texture or leave them out altogether (ch. 17, sec. 6.20, p. 232).