I thought it would be interesting to compare mouth opening shape and degree between classical tenors and musical theatre belters. In both tenor acuti and belting, vowels are rather open, so the O in “blow” becomes something more like /ʌ/ or /ɑ/. I have cued these up to the appropriate parts of the video so that you only need to watch each for less than a minute.
All singing the same phrase from “Salut, demeure chate et pure” from Gounod’s “Faust” –
the high note is a C5 on /a/ (the end of the French word “presence”)
Nicolai Gedda https://youtu.be/-m_Jas-OEFE?t=5m11s
Juan Diego Florez https://youtu.be/VHgdcGHx0XI?t=5m15s
Alfredo Kraus https://youtu.be/oPD1-uQh_EQ?t=4m48s
Jussi Bjoerling https://youtu.be/oImARrFg5E8?t=4m5s
Carol Burnett C#5 on “…gets your heart” from “A boy like that/I have a love” from “West Side Story” https://youtu.be/3QAGHYD-jm4?t=1m3s Also notice the “cry” in the voice at the beginning of the clip. This is taught to many tenors. Carol used it often in her singing.
Sutton Foster (last “Gabriel”) C5 from “Blow Gabriel, Blow” from “Anything Goes” (in B-flat) https://youtu.be/L-Ql-fduIdM?t=3m30s
Patti LuPone several C5s in “Blow Gabriel, Blow” from “Anything Goes” (in C) https://youtu.be/XBsrmeciHQo?t=13m14s
Ethel Merman several C5s in “Blow Gabriel, Blow” from “Anything Goes” (in C) https://youtu.be/KmhC_M93bLA?t=3m8s