Anyone used the Pure Sound for wound string cores? Terry Farrell ----- Original Message ----- From: "John Delacour" <JD@Pianomaker.co.uk> To: <pianotech@ptg.org> Sent: Friday, May 10, 2002 5:38 AM Subject: Re: Piano Wire > At 9:06 pm -0700 9/5/02, Joseph Garrett wrote: > > | My next trial wire will be the > | "Pure Tone" stuff. I am curious and would like to try it. The problem there > | is I need to find out what the math/density coeficient is for the scaling > | program. Any one have a thought on that? > > The specifications are at the web site <http://www.puresound-wire.com/> > The specific gravity is higher (7.9+ v. 7.85 for common wire) and the tensile strength is significantly lower, though he now makes a few of the thinner gauges with a higher breaking strain, so you need more tension to bring the string to pitch while the wire will break at a lower tension -- not what I'd call an ideal state of affairs! > > Note C64 with length 18.1 cm. will come to pitch (A=440) at 170.2 lbf. using standard wire of density 7.85 g/cc. Using the higher density wire, a tension of 171.3 lbf will be required. I append a perl script detailing the calculation. So you see that the increase in tension is insignificant, whereas the much lower breaking strain is important and must be taken into account. > > JD > > #perl -w > ( $note, $length, $diameter ) = qw~ > 64 18.1 0.0925 ~ ; > > ( $rho, $a49, $g45 ) = qw~ > 7.85 440 980616 ~ ; > > $K = $g45 / 3.14159265358979 / $rho / 2.205 ; > $frequency = $a49 * (2 ** (1/12)) ** ($note - 49) ; > $tension = sprintf "%.1f", > ($length * $diameter * $frequency)**2 / $K ; > print "Tension: $tension lbf.\n" ; > > #### -> Tension: 170.2 lbf. > #### _____________________ > > >
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