[CAUT] Tenor thonk

[Greg Newell]

Ron,
         Thanks for sharing the info about your 
commission. That's good news! Congratulations!!! 
Care to share which manufacture did the commissioning?


best,
Greg Newell


At 05:47 PM 8/28/2006, you wrote:
>Hello Alan and all,
>
>>I'm working over a Chickering grand, about a 6 footer or a shade longer. The
>>bass on this piano reminds me of a M&H BB, big and boomy. Running a
>>chromatic scale up from the bass there is an obvious transition problem when
>>you get to the tenor.
>
>Yep, the chromatic-run test is the one which shows up a problem.
>
>>  It is kind of a nasal "thonk." Funny thing is though
>>when you run the chromatic scale down the tenor and into the bass, the
>>transition doesn't sound as obviously poor. Tenor sounds reasonably decent -
>>not big and boomy, but not thin either, fairly round but just doesn't
>>project or have the swell like the bass. I have done all I think possible
>>with hammer voicing to even it out. I'm thinking it is a board/bridge/string
>>issue of mass (too much or too little?). Or impedance? Or, ??? Short of
>>board re-design, anyone have any suggestions for improving this transition?
>>
>>It is in a lively classroom. It is not used for performance, but is used for
>>chamber practice and such. Not the highest priority situation, so re-design
>>is not an option. But it is a decent piano and worth keeping around.
>
> From what you describe it might be a case of 
> too little weight in the low tenor, combined 
> with too much board activity at the high end of 
> the bass bridge. The treble bridge will be a 
> lot lower in height than the bass bridge, so 
> there's often a weight difference which can 
> easily be addressed by adding a brass weight or 
> two to the soundboard buttons, as Ed suggested.
>
>As Ron N mentioned, the scale is an area which 
>may provide some enlightenment also. You can add 
>weights on top of sound board buttons by using 
>longer screws with the same diameter and thread 
>pitch. This will allow you to add quite a bit of 
>weight if necessary. From what you describe it 
>sounds as if the high end of the bass bridge 
>might be placed too far out from the perimeter 
>of the board. This is a common problem and it 
>often results in a 'boomy' high end of the bass. 
>One trick which may help you is to place a dowel 
>between a back beam and the sound board, placing 
>it at a strategic distance to reduce soundboard 
>activity some, but not too much. I've done this 
>several times to help a cross-over which is 
>uneven. It becomes a piano with a sound-post but it works.
>
>Another 'suck it and see' test you can perform 
>is tapping the bridges at the cross over, 
>listening to the characteristic thump of the 
>sound board at each end of the two bridges. In 
>pianos which have a good crossover, the thump 
>characteristics of the bridge ends will sound 
>very similar. When the cross is ordinary you'll 
>often hear a thump which is much darker on one 
>of the bridge ends (usually it will be the 
>bass). When a piano is strung, I perform this 
>relative-thump test by placing a clean piece of 
>cotton cloth on the bridge to avoid touching the 
>strings. This test will still give you an 
>indication, even though the piano is strung.
>
>When rebuilding pianos. when the piano is 
>stripped we habitually tap the board at the 
>bridge ends in an attempt to determine if the 
>soundboard activity levels match. For many 
>pianos, we've tapered the board at various 
>places, added weight and extended the foot of 
>the bridges as necessary, to modify the 
>soundboard activity levels before re-assembly.
>
>Its always easier to make fundamental changes 
>when a piano is stripped, rather than applying 
>the limited options available once the piano is 
>re-assembled. When you strike a piano that's 
>together its harder, but its nonetheless 
>surprising what can be achieved. Fixing scale 
>problems will require a tear-down, but sound 
>board activity problems can often be helped with 
>judicious use of weights and hardwood dowels.
>
>What I find staggering is how some manufacturers 
>can build the same instrument for decade after 
>decade without asking the question of what makes 
>a certain instrument sound the way it does. Many 
>of the problems we hear must have been in the original piano at day one.
>
>Designing a new model is such an exciting time, 
>with the opportunity at hand to make a real 
>difference. I have received my first commission 
>to design a new piano for another manufacturer. 
>The piano in question is a 131 cm upright. The 
>current piano made by this manufacturer has so 
>many problems it will need a totally new scale, 
>plate and sound board. This is a new challenge 
>for me since I have a 133 cm design exercise 
>which I did back in 1996. Some of my tone 
>building ideas have evolved since then, but a 
>lot of the design remains valid. I'm currently 
>laying up the sound board area, scaling, back 
>scale and note spacing. Since I have decided not 
>to manufacture any upright pianos myself, all of 
>my design ideas from  the 1996 concept can be 
>incorporated into the new 131 design.
>
>I expect to be building the prototype by 
>December. The manufacturer is sending me a 
>semi-built shell, without a sound board or 
>plate. I'll build the protoype into the existing 
>case to save the cost of re-tooling for the case.
>
>Regards,
>Ron O.
>--
>OVERS PIANOS - SYDNEY
>    Grand Piano Manufacturers
>_______________________
>
>Web http://overspianos.com.au
>mailto:ron at overspianos.com.au
>_______________________

Greg Newell
Greg's Piano Forté
mailto:gnewell at ameritech.net
www.gregspianoforte.com  
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