In case you play a transposing musical instrument, such as saxophone or clarinet, we have a good news for you.
We added an option in our Absolute Pitch Trainer that allows you to transpose notes.
Note that in the exercises for perfect pitch development we recommend starting with the notes F# and D#. Usually these notes are easier to identify for someone with untrained ear. These are concert pitch F# and D#. If you play a transposing instrument, you will need to figure out which note you should play in order to produce these sounds.