Calculating Stike Point "Ratio"

[RicB]

Hi Joe

Thanks for the post... the strike ratio bit I got alright.  But you do 
raise a good point for me to check before placing and notching the new 
bridge.  The new blank is an <<exact>> copy of the old footprint.  The 
top leaves a good deal of room for changing the string lengths via 
notching if I choose too. Combined with a slight move aft of the whole 
long bridge I could get radical enough for sure.  Pointing out the need 
to check clearance for the hammers in the treble was exactly the kind of 
thing I need to hear. I will check that tomorrow.  Yes I do have the old 
scale data so no problemo there.

I think I'm going to end up with about a 4 mm length increase in the 
highest notes.  Even with puresound its hard to get anything that looks 
even remotely reasonable with a shorter length on my spreadsheet. 
Inharmonicity is way off the chart as is... and its really uneven.  If 
anyone wants the basic scale data, ie string lengths and diameters... 
I'd be glad to provide it.

Cheers
RicB


    Joe writes:

    Hmmm? I think you get it, but not sure.<G> I assume you have the
    Olde Scale. Stuff the action into the piano; measure where the
    Original Hammers Strike point is; take that number and the number of
    that notes string length; do the math ....and you'll have a "ratio"
    or "fraction", if you will. (i.e. 1/6th, 1/10th, etc.) That should
    give you a starting "point" to aim for in the New strike point.
    Because the action and belly rail can only be varied a limited
    amount, you may have to make some compremises to physically make it
    work. (think: large can of worms<G>)

    The bass should not be too much of a problem. However, the upper
    treble will be, as there is the likelyhood that the belly rail will
    not allow you clearance for that longer string. As you know, the
    slightest addition/subtraction of strike point, in that area, makes
    a huge difference in tone production. Personally, I wouldn't get to
    "radical" in the top treble string lengths. As for the calculating
    formulae that takes "Harmonicity" as the criteria...I can't comment
    on it, other than to say that that is what we REALLY are trying to
    do in Scaling, is to attempt to make all of the dominant Harmonics
    match. In the real world that just is not possible, IMO, although it
    would be nice. Kinda' like calcing the longetudinal inharmonicity of
    bass strings: looks good on paper, but doesn't really make for good
    piano sound in the real world.<G>

    Have fun.



Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I