Bass string making (was Hex Roslau wire?)

[Stephen Powell]

Hi Carl.  Good grief - what a lot of questions!


>Stephen,  Thank you for the info.  I have many questions regarding bass
>strings.  Glad to find someone who is making them.


There seems to be very little written on the making of bass strings and to
me it has seemed to be one of the most mysterious parts of piano
manufacture.

>I know that many share your view that hex core doesn't give good tone.  I
>can't say that I have enough experience to notice.
>Now, do you have any idea why that is true if it is?
>Could the process (whatever it is) affect tone?
>Could the scaling formulas be wrong for hex wire?
>Is the tension or inharmonicity different and why?
>I just can't put my finger on any logical reason that hex core would sound
>different than plain wire.  Could it be that they just take round wire and
>run it thru a die and then don't anneal it or use some other process to
>finish it?  I'm really curious.


Can't help you much here; all I know is that the Knight pianos (English)
with the hex bass strings sounded a lot murkier than normal.  But it is a
while since I heard one and I wasn't making strings then; I pay more
attention next time.

>I routinely use wound strings above the bass break for two to six notes.  I
>usually convert those notes from trichords to bichords. Many pianos have
>low tension and high inharmonicity at those notes and if you can smooth out
>those curves, the piano should be more musical since that area is where the
>left hand plays and it will blend in with the notes up a couple of octaves
>where the right hand plays.
>
>It has been difficult to get strings made accurately (at a decent price)
>when the exposed core is the most critical measurement.  That's the
>measurement that is hard to get.  It is usually
>necessary to increase the exposed core at this area to increase the
>inharmonicity to fit the curve.
>
>So now, If I wind some strings with hex core and intentionally make the
>windings a bit long on each end, I can remove some winding after the string
>is up to pitch to get the exact exposed core I want.  A quarter inch change
>in exposed core makes a big  change in inharmonicity, but
>little change in tension.


Yes to all of the above.  I use Pscale which puts the ends of the winding
where I want.

>This increase in exposed core is necessary since copper  is not available
>in infinitely small sizes (you couldn't handle it anyway) Soooooooo, what
>about aluminum wrap?  If the shape of the wire affects tone, would the
>aluminum wrap sound good, bad or ugly just because it's aluminum? I wish I
>knew.


Have absolutely no experience with aluminum winding, sorry.

>Since you make bass strings, I wonder if you'd share some information.
>What is the desired tension of the core wire during winding and does it
>depend on size? What is the effect if the tension is too high or too low?
>What is the desired tension of the wrap wire during winding and I assume
>this would vary greatly with size.  I think I have a chart somewhere that
>lists the tensions for winding coils for electronic components. I've
>watched bass strings being made and I'm surprised that a leather gloved
>hand is the only calibration used.  Oh, well! Let's hope the winder doesn't
>have a hangover when he makes my strings.


There probably is some theoritical optimum for core tension, but I don't
know what it is.  What I do know is that changing the core tension according
to size doesn't seem to be nesseccary.  I feed the wrap by hand (with the
leather glove!) as it has been done tradionally, and yes, the tension varies
greatly with the wrap size - the fine copper breaks easily.  It would be
nice to havwe some CNC automatic feed system, but I guess I'll just have to
save drinking until *after* i've wound the bichords!!  Actually, it did'nt
take much practice to get the hang of winding bass strings and i make all my
own and wind for others too.

>Carl Meyer
>Santa Clara, Ca.

Hope this was some help.

Regards,

Stephen Powell, RPT
Auckland, NZ