Apple Using the GarageBand Jam Pack: World Music Instruments - Manual (Page 18)

18
Tango Accordion
In addition to its use as a polka instrument (described in the previous section),
the accordion has also been frequently used in performances of Argentine tango.
Tango accordions are typically larger and have a tone quality and voicings different
from polka accordions, but are constructed and played in the same manner.
Pianos and Keyboards
Instrument Controller Info
Afro-Cuban Upright Piano  Velocity adds attack and volume.
Polka Accordion  Pitchbend controls volume.
 Velocity controls speed of attack.
Tango Accordion  Pitchbend controls volume.