Tubby bass strings

[Tom J Armstrong]

I often loosen and re tighten tubby bass strings to brighten the tone. 
Sometimes it works, other times retwisting the strings is more effective.
 I understand why retwisting a bass string can make it vibrate more
efficiently.  The copper wrap is "tightened" somewhat by that procedure,
allowing the winding and core to vibrate as a unit.  For some reason,
iron wrap does not usually respond to either procedure.  

Just this week I experienced a nice Yamaha G3 that benefited immensely
from "L & R".   I am curious why merely loosening and retightening works.
 Does anyone out there really know?

Tom Armstrong