Compression ridges was :Do you..

[David Love]

Adding mass to the low tenor was to help tone down the bottom of the tenor
section where it transitions to the bass.  The loud honk that occurs down
there is attributed to the end of the bridge effect where the mass and
stiffness are reduced and the last note or two can be too loud (there are
scale issues as well).  Adding mass at the end of the tenor bridge can help
control that effect.  It's not a perfect solution but it can help.  The
better solution is to redesign the scale and add a short transition bridge
for notes 27 through 32.  

David Love
davidlovepianos at comcast.net 
www.davidlovepianos.com

...I seem to remember a while back that David Love (I could 
be wrong) posted something about adding mass to the tenor end of the long 
bridge on an M, and how that made the tone so much better...
Clark A. Sprague, RPT