What’s the difference between dynamic and open calling in voice grouping? Under what circumstances are they used respectively?
Different voicings. Dynamic has a bass note and inversions for smoother transitions between chords (voice leading). Open Voicing:
'A style of musical arranging or orchestration in which the notes of chords are assigned across a range wider than one octave. The lowest note of an open voicing is almost always the root of the chord; occasionally it may be the fifth.
Here’s a simple example of open voicing: Start with a C Major triad Middle C (C3), E, and G. Now move the C down one octave (to C2). Next lower the G one octave, to G2. Leave the E where it is and add a high C (C4). C2 – G2 – E3 – C4 is the resulting open-voiced chord, spanning two octaves.’
For beginners like me, it’s OK to use dynamic, isn’t it?
It’s perfect. I use it all the time. Just your regular chord with some thickener applied!