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<DIV><FONT face=Arial size=2>Hello Ed.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I can not claim that I have a long time experience
using Pure Sound wire. But I did some tests when I was about to restring a
1864 Pleyel piano.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Pure Sound is a bit heavier wire than Röslau : it's
volumetric mass is 7900 kg/mł, while Röslau's is 7850 Kg/mł.</FONT></DIV>
<DIV><FONT face=Arial size=2>This means that if you use the same speaking
lengths and the same diameters, you will need a bit more tension with Pure Sound
to achieve the same frequency. Well, not much difference at this level
between the two materials.</FONT></DIV>
<DIV><FONT face=Arial size=2>More significant difference is in the elasticity
modulus (Young's modulus), which tells about how easily the material bends or
stretches. This is 187.5 kN/mm˛ for Pure Sound, while 210 kN/mm˛
for Röslau (those numbers represent the stress in kN to apply theoretically to a
1mm˛ section wire in order to double it's length). So, while slightly
heavier material, Pure Sound is more flexible.</FONT></DIV>
<DIV><FONT face=Arial size=2>Another difference of practical use when stringing
is the breaking strength. In my example of a A4 wire of 0.85 mm diameter,
Pure Sound would break at 113.8 kg force while Röslau at 137 kg force. So,
Pure Sound breaks earlier when tension rises, or, for a same speaking length and
same diameter string at same pitch, will be closer to breaking strength than
Röslau.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>My tests were intended to make the link with the
practical world of piano shop and the subjective appreciation of the sound given
in situation by those different strings. I limited myself to installing
side by side a Röslau string and a Pure Sound string on the same unisson at 3
different octaves with appropriate and similar gauge, and explore the sound
quality of single note, octave and double octave when progressively rising the
tension.</FONT></DIV>
<DIV><FONT face=Arial size=2>So I first tuned the strings at their "normal"
pitch, that is at the frequency of the note as compared to A4 = 440 Hz, and
waited for a week or so, doing many tunings until the strings were a bit
stabilized. First remark : Pure Sound was much quicker stable than Röslau.
<DIV><FONT face=Arial size=2>When compared at that normal pitch, the intuitive
feeling is that Pure Sound has less subjective inharmonicity, I mean that a
single note sounds indeed more pure than the same note with Röslau, more calm
sound if you see what I mean. This is due, I think, to the smaller
elasticity modulus, allowing the wire to bend easier at the termination
points. Now, when playing octaves, the good feeling of low inharmonicity
seems to be decieving, turning into a lack of character. Also (but not
really sure of that) I had a feeling of less power with Pure Sound.
Difficult to say with one string.</FONT></DIV>
<DIV>Then I started tweeking the tensions to simulate what if I would rescale
with other tensions.</DIV></FONT></DIV>
<DIV><FONT face=Arial size=2>Röslau wire broke in the piano at an augmented
fourth above it's normal pitch (compared to A4 = 440 Hz), and Pure Sound broke
at only a major third above it's normal pitch.</FONT></DIV>
<DIV><FONT face=Arial size=2>Röslau sounds awful when tensionned less than a
major second below it's intended pitch, sounds great when at pitch, and looses
much interest and sustain when pulled over pitch. C4 lasting 18 seconds
(approximately, from what I could hear) reduces it's sustain to only 9 seconds
when pulled up to the pitch of F#4.</FONT></DIV>
<DIV><FONT face=Arial size=2>Pure Sound, indeed, still sounds acceptable even a
major third under it's normal pitch, but has the same tendency to loose interest
at higher tensions.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>What I for now retain of my experiment (before
other experiments confirm or infirm this, of course), is that Pure Sound accepts
(as claimed by Juan mŕs Cabré) to be lower tensionned than equivalent Röslau
gauge (and probably gaining so a bit inharmonicity, which I believe is necessary
for a good piano sound). I see no valid point in trying to string as close
as possible to the material breaking strength (as claimed long ago by Mersenne,
but he was talking violin and cat guts) as in my opinion the sound gets
progressively less interesting and certainly less long lasting in that area (not
talking about the thump sound that gets really ennoying). So I would tend
to choose Pure Sound for older shorter scales indeed, in a low tension
figure.</FONT></DIV>
<DIV><FONT face=Arial size=2>Anyway, I feel that when choosing Pure Sound wire a
rescaling would be needed, if possible by ear. Retaining the original
scaling gauges for the sake of respecting the original makes no sense to me in
this case.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Of course, one can only juge on a whole stringing
job that has streched for many month, in order to give a pertinent aesthetic
value to the result. Then, restring the same piano with other scaling
and/or other material, see if it improves the whole figure.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I hope others with experience with Pure Sound will
chime in and share their founds.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>P.s. : I ended up stringing the 1864 Pleyel with
Röslau, because the Röslau wire sounded great when matching the scaling gauges
that were there (possibly not original, though). I believe Pleyel has been
very quick to import, copy and improve English steel, and the model I was
working on was evidently a straight forward one.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>p.s. 2 : long ago, I restringed a 1895 Bechstein
model D (240 cm) with Pure Sound, retaining original gauges. The piano
lacked interest and charm, for sure, but was this due to stringing or to
something else ? Dunno. Anyway, I'm sure now that for Bechstein
pianos, from the start (1853), Röslau is a better choice, better matching the
original material.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Best regards.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Stéphane Collin.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ed440@mindspring.com
href="mailto:ed440@mindspring.com">ed440@mindspring.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">Pianotech List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, July 26, 2006 2:54
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Pure Sound (was A 435 or A 440
?)</DIV>
<DIV><BR></DIV>
<DIV>Stephane-</DIV>
<DIV>Would you tell us your impressions of Pure Sound wire?</DIV>
<DIV>Ed Sutton<BR><BR><BR></DIV>
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