I have recently observed, on Youtube, a very interesting method of turning any barbershop tag into a jazzy eight part tag: simply double each part a perfect fifth higher. Or, said another way, have a second quartet simultaneously sing the same tag a fifth above.
Despite everything I was taught in college, I have been curious to try this myself. However, due to sound bleed-through from my upstairs neighbors, I can’t really record in my apartment these days. So I multitracked this one tonight in my car on my Zoom H4. Although I am sure I looked quite suspicious, I think it was worth it.
You can hear the original four part arrangement here.