[CAUT] Carbon Fiber Soundboard

[Richard Brekne]

Hi folks

I havnt had time to post anything about this years Nordic Pianotreff in 
Helsinki.  There was actually (again) quite a lot of interesting things 
presented there this year. I like to think that we in Scandinavia have 
established the best of the European Piano meets. In particular this 
year was one  Richard Dain of Hurstwood Farm Piano Studios, who has 
allied himself with Steingræber & Sohns (who'm was also there this 
year).  Together they were showing the new Phoenix Grand... a  232 cm 
long affair using a new variant of the bridge agraffe.  The special bit 
with these agraffes is that the string supports are free floating, which 
allows the string to force them downwards onto the bridge independent of 
the overall downwards pressure on the soundboard.  Dain has figures to 
assert that the contact between strings and bridge is strengthened quite 
significantly. He also presented evidence that this agraffe solution 
increased the overall efficiency of the whole system to transfer string 
energy into soundboard output.  He claimed in informal discussion as 
well that the sustain obtained by this system is superior to the Stuart 
and other solutions. And interestingly enough he had data which showed 
that the increase in sustain had nothing to do with the increase in 
mass.  He had altered the amount of mass used in each agraffe by several 
grams using different types of seating screws and was not able to 
measure any change in performance related to the mass change.  He also 
was firmly of the opinion that the reason for the increased sustain was 
this bit about the string vibrating in a vertical mode longer. I of 
course mentioned some of the stuff we've talked about through the years 
on these lists. His response was that the soundboards ability to vibrate 
in a vertical direction with great easy compared to sideways was not the 
issue here. We didnt get time to go further into it.  The fellow is a 
retired engineer... quite successful one evidently as he was able to 
fully finance the design and building of the Phoenix as I understand it.

The other bit he showed was a slice of a Carbon fiber soundboard 
material. It was actually a laminate construction with two outer layers 
of spruce and an inner layer of carbon fiber.  Quite a bit thinner then 
a standard soundboard.  I understand he is getting ready to produce 
instruments with this stuff soon.

Interested can find him at http://www.hurstwoodfarmpianos.co.uk/index.php

Cheers
RicB