As far as I know it's always been Acousticon Shells..I have used both 18 and 20 " Kick drums and have always been happy with the results in recordings...but as you well know that every studio makes the same drums sound just a little bit different,
The best two studios for me in this part of Texas are Firestation in San Marcos and Willie's studio in Spicewood.Also the last CD I recorded was live at Antones with the Tornados and that was a mobile studio.On that recording I used a 20" Remo Kick, 12 & 13 "Fibes mounted toms with Rims a 14"Remo floor and a 14 X 5 1/2 Pearl Pawn Shop special snare...and of course all Paiste cymbals.
I was very happy with my overall sound.CD is close to Gold.
