Bluthner Tuning

[A440A@aol.com]

Susan writes:

<< Take out the last mute, and see what happens to the 

unison and its timbre, when played normally. Often it starts to sound 

crummy. Pluck the fourth string to be sure it isn't out in left field, and 

then move it a very short distance up and down, until the unison rings 

sweetly again.   The timbre of the unison 

determines where the fourth string is tuned, not its exact pitch, but it 

should be close to the others. << 

   Greetings, 
     I have found that the Bluther's extra string gives me the best results 
when it is tuned just slightly flatter than the unison.  I think it is because 
of the phase interaction, operating through the Weinreich-described coupling 
at the bridge, produces more sustain.  
     When the frequency of the impelling force (the unison) is lower than the 
resonant period of the structure upon which it is acting, (the fourth 
string), the two will always be in phase.  If the impelling frequency is higher, the 
two will be out of phase.  It is this out of phase arrangement that augments 
sustain. 
      Think of pushing a swing;  if the swing takes 5 seconds to go out and 
return, and you give it a push every 5.1 seconds, you will always be helping it 
go away from you.  If you push it ever 4.9 seconds, you will be resisting it 
every cycle. By creating this micro-resistance between the unison and the 
sympathetic fourth string, I believe that it takes longer for the unison's energy 
to pass through the bridge, thus more sustain. 
    If I tune the fourth string higher, the tone seems to be more brilliant 
or louder, but of shorter duration.  
Just a thought, 
Regards,  
Ed Foote