Drop D at an even 18/16. If you want to overlay the keyboard part, its reverb amounts to 
triplets over each beat of this melody.

e|-----------------------------------------------------------------------|
B|-----------------------------------------------------------------------|
G|9---------------------5-7---------------------3-5----------------------|
D|--7---9-------2-5-4-7-----5---7-------0-3-2-5-----3---5---------0-0-3-5|
A|----5---7---2---------------3---5---0---------------0---3-----3--------|
D|----------5-----------------------3-----------------------0-5----------|