I usually find all the music creation tools unnecessary complicated for the task I want to do during the jam. This time I used Bandlab as it is super user-friendly and has a large library of synths and loops there for free. Also it's available from browser.

Created music for Tiny Inc. Repair shop (https://ldjam.com/events/ludum-dare/56/tiny-inc-repair-shop) in ~20 minutes while was waiting for Unity to build the project. What do you use for music creation?