Watch the Reggae Bassline online guitar lesson by Vicki Genfan from 30 Strumming Patterns You MUST Know
I'm using a Gm-Cm. Both chords are using the top 4 strings. The double hit has a very different feel than in the first reggae pattern we worked with. However, the difference is very subtle. Both of the two hits are very short and staccato. In the previous pattern we leaned more heavily on that first double hit. Try both and see which you like better. Listen to some of your favorite reggae songs and see if you can hear the difference.
When you play the bass line, make sure your last note is on the up beat of 4.