An organ trio is a type of jazz band with three musicians . While the term `` organ trio '' is typically a reference to a type of small ensemble , the term `` organ trio '' is also used to refer to the musical styles , genres , and tradition of the 1950s\/1960s era of organ trio playing . Although the components of the `` organ trio tradition '' are a subject of debate , the 1950s\/1960s organ trio style tends to have more blues influences than other small-group jazz from this era , and it often blurs the lines between blues , R&B , and jazz .