One of the exercises I give to my students to practise triads is this one.
I let them play the triads of Am & Em up and down the neck - works bot ways. While playing the triad on the G-B-E string and also on the D-G-B string they have to alternate in addition the bass note on the open E & A. So the open E while playing an Em triad and the open A while playing an Am triad.
Written by Peter Bos
Other exercises available here -> see section on daily exercises
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