Hello,
I supose its not the synthetic core thats your problem its the pitch
or the string lenght. there are four d's in use on the hurdy gurdy:
the four pitches
d'' - the high chanter of the D tuning (one note lower than violins e'')
d' - the low chanter of the D tuning and the typical trompette (the
violins d')
d - the "petit bourdon" - the higher drone (the cello d)
D - the lower drone (one note above cello C)
for the "petit bourdon" d a cello d string might work if the open
string lenght is roughly the same as the hurdy gurdy ones - this is
how the 1/8 cello came into discussion. The differences between 4/4
cello and 1/8 cello strings are serious and its impossible to replace
the one with the other.
The string dimensions possible for a certain pitch also vary deeply.
Not all hurdy gurdies share the same open string length and
construction, not all players share te same sound ideal. For example
Northern Renaissance Instruments alone offers the following dimensions
for the "petit bourdon"-d (in mm gut equivalent) 1.62, 1.82, 2.04,
2.29. That is a range that could also easily cover a full octave!
The cello d is one note higher than the viola c. As the standard
violas open string lenght is roughly the same as most hurdy gurdy
drones its quite likely to find a fitting viola string.
Synthetic strings are used as standard strings for hurdy gurdy for at
least 20 years now, used as chanters, trompettes and drones. If the
string you bought is not fitting your needs its just the wrong string.
By the way, the price for a silver plated copper wound gut string in
the dimensions needed is also about 20 - 25 Euro.
I still think you should ask Helmut Gotschy what to use.
kind regards,
Simon Wascher - Vienna, Austria