Talk:Channels/@comment-216.82.155.93-20190302223808/@comment-34747221-20190303054402

Click the button on the upper-right that says Edit. When the dropdown options from it appear, click Custom song size...

From the menu that pops up, change the values of Number of pitch channels: and Number of drum channels:. When you're finished choosing the values, click Okay to save the settings.