The Encyclopedia of Double Bass Drumming by Bobby Rondinelli et al, teaches that you can gain immensely from using two bass drums rather than a double pedal.  This book adds to the world of drum knowledge and revolutionised the traditional approach to drumming and opened up a new world of ideas for the drummer.  A book of historic importance for all drummers everywhere.  From West London Drum Tutor, drum lessons in Harrow, London http://paltip.com/westlondonenglish/!526m