Info at these links might be helpful to the current discussion.
From TNT Audio...
http://www.tnt-audio.com/clinica/spkcbl_e.html
http://www.tnt-audio.com/clinica/intere.html
From TNT Audio...
http://www.tnt-audio.com/clinica/spkcbl_e.html
http://www.tnt-audio.com/clinica/intere.html