Nine limit tetrads

The nine-limit just intonation tetrads are subchords of the full nine-limit pentads, omitting one element.

3-5-7-9

These are the otonal subminor tetrad, 1-7/6-3/2-5/3, and the utonal supermajor tetrad, 1-9/7-3/2-9/5, with steps 7/6-9/7-10/9-6/5 and 9/7-7/6-6/5-10/9.

1-5-7-9

These are the otonal, 1-9/8-5/4-7/4 and the utonal, 1-7/5-14/9-7/4, with steps 9/8-10/9-7/5-8/7 and 7/5-10/9-9/8-8/7.

1-3-7-9

These are the otonal, 1-9/8-3/2-7/4, and the utonal, 1-4/3-3/2-12/7, with steps 9/8-4/3-7/6-8/7 and 4/3-9/8-8/7-7/6.

1-3-5-9

These are the otonal, 1-9/8-5/4-3/2, sometimes called add2, and the utonal, 1-6/5-4/3-3/2, with steps 9/8-10/9-6/5-4/3 and 6/5-10/9-9/8-4/3 respectively.