Piano treble and bass volumes

It is easy to adjust volumes on instrumental parts by simply using the mixer. But in a piano part, is it possible to adjust the volume of the treble and bass clefts separately. The problem is that my bass cleff is too loud. If I were to separate the parts and put the bass cleft on a separate piano instrument, that could work. But, if the piano treble and bass are on the same piano instrument, is there a way to adjust the volumes? I hope this is an understandable explanation of the problem.