I would appreciate some advice from any Alesis SR16 users.

Do you know how to add/remove beats from the pattern length? Although I am able to edit the USER PATTERN, I am unable to edit the USER SONG. (Also, when I edit the user pattern I cannot listen to the results because there is no sound.)

Do you add/subtract beats prior to or after composing a user song? Or do you record it as a user pattern and transfer it to a user song format afterwards?

Thanks, Bobby

The pattern length has to be set before you record notes in it. I never tried to alter it after the fact, but I doubt that they will allow it to be a different value then the total of beats recorded into the pattern.
I haven't had a 16 for a few years, but as I remember - it was a snap to start from scratch .... just make a new pattern, and make it your own custom length.