mesh modifications of the added holes available at :
https://cad.onshape.com/documents/0729820334672d5afa0db25c/w/c2fbe1252151d7ab84968640/e/54231ea8e73d82eaa129534b
sorry I didn't have the base mesh so the base .stl is imported as-is.
The author remixed this model.
added 2x Mic Ports holes on the holding arms