[CAUT] killer octave resonator

[Ron Overs]

Ric and all,

Ric, I agree with you that stiffening the rim/belly rail assembly 
isn't going to fix a piano with a dead board. If it was that easy 
then surely all of these pianos with this problem must have had it 
since new. Furthermore, mass loading the board won't help either if 
it has insufficient stiffness (yes we have tried it).

Certainly, stiffening the rim is likely to aid sustain, but the more 
of this work I do the more I am convinced that the board is the 
primary determining factor with respect to impedance and tonal 
character. The plate also plays a part. Someone wrote on the list 
about the idea of improving the treble sections by mass loading the 
plate. I agree that this will help if the hitch-web is light (the S&S 
D hitch plate is only about 8 mm thick, along with many others whose 
plates are even lighter - Baldwin SD-10 excepted). This is also why 
fitting a back beam in place of the bell also works. It helps to mass 
load the plate along with an increase in hitch-web stiffness. This is 
also why I don't use lossy-and-light spruce or pine for the extra 
back beam. I use hardwood which is at least as dense as Rock Maple.

This whole topic of tone building always gets messy because there are 
so many factors which go into the mix. We tend to give weight to 
certain factors based on experience. Its also what makes the field so 
interesting.

Ron O.

>Hi Chris
>
>I am reasonably comfortable with how it does what it is supposed to 
>do.... at least I think I am... I just dont see how it can 
>substantially cure an already acute killer octave situation... and I 
>am not sure I see how it prevents one.
>
>The reason for this lack of understanding on my part is because I 
>have interpreted the <<killer octave syndrom>> to be equivalent with 
>a failure of the soundboard rib assembly to support downbearing at 
>the effected area.  So it seems to me that a strong enough support 
>directly under the bridge at this area is what would be needed to 
>prevent that.  I dont see how increasing the stiffness of the belly 
>rail provides that.
>
>Misunderstand me not.... I am not saying anything along the lines of 
><< I'm not a believer >>... I just wish someone would go into detail 
>to explain the relationship between a stiffer belly rail and how 
>this lessens the likelihood or degree of a case of killer octave 
>syndrom. 
>
>Perhaps my understanding of what a killer octave is to begin with 
>needs correcting..... ?
>
>As I believe I am probably not alone in a bit of head scratching 
>here.... I think it would be benificial for those who have some 
>insights into this to expound a bit on the whole matter.... both 
>exactly what the killer octave really is, its causes etc etc etc... 
>and how a stiffer belly rail relates to it.
>
>Thanks.
>
>btw... I have one of these devices... and just havent gotten so far 
>as to installing it on an appropriate instrument.
>
>Cheers
>RicB


-- 
OVERS PIANOS - SYDNEY
    Grand Piano Manufacturers
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mailto:ron at overspianos.com.au
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