Ensemble by trio can be done by duet.
Since each chord has a bass sound, it is possible to express like playing a bass and a chord harmonica only with BCH-48, enabling an ensemble equal to trio by duet. Adopted a single reed for chord and a heavy double reed with different octave for the bass.
Major and seventh chords are assigned to the upper, minor and diminish/augment are assigned to the lower on hamonica. Total 48 chords can be played, such as 24 chords by blowing/breathing on the major, 24 chords by blowing/breathing on the minor.