Mark found himself very busy during his musical career,  playing, recording and touring professionally with a mix of local groups and recording acts throughout California, the Pacific Northwest, and Mid-West. Mark stepped away from the music business for several  years to raise a family. With the kids now grown, Mark is back pursuing his passion for drumming and is thoroughly enjoying playing with the original “Backbone” line up. 

Ron Denhaan - Bass & Vocals 

Born in Europe (Holland), Ron has lived on both the east and west coasts of the United States. Though starting off as a lead guitarist, Ron has been playing bass guitar over the years with a number of hard-rock, pop-rock, progressive-rock and jazz/horn groups. In 2008, Ron reunited with several of his band mates from the groups "Shade" and  "Lyra", as well as the  "SubsoniX", which includes all five of the original members of  the group, "Backbone".  Ron plays 4-string, 5-string, and fretless basses with the SubSoniX. 

Scott was an original member of Backbone, but Orange County native Scott Plunkett might be considered a part-time member of SubnsoniX, as he is often touring and recording with singer/song writer Chris Issak. After turning professional, Scott played with a variety of local and professional bands and musicians including Boz Skaggs.  During his tour with Boz, Scott also wrote and played with local bands, did recording sessions, and co-wrote songs with Michael McDonald. Over the years, Scott has toured with Michael McDonald, Stevie Nicks and Don Henley. Scott has also acted as the musical director for Peter Cetera and Boz Scaggs.  When he’s not performing, Scott designs synthesizer sound patches for the Yamaha Corporation’s latest electronic instruments.