Eric Henry's Vocal Booth

Hello, Can anyone give more details about this vocal booth? Like dimensions and materials. I plan on building on myself but I'm concerned about the size of my space: 8.5'h x 3.75'w x 6'l. Is this too small for a good vocal booth? Thanks, Tom

The size is correct acoustically, but the balance, feel or comfort should be a major consideration. My vocal booth is 6ft. x 8ft. x 9ft h and with it's proper acoustical treatment this room is a joy to work in, even with a drum set, oh and don't forget really good Mic's.