Technical data
| Core | spiral steel |
| Line | Spirocore |
| Instrument | Cello |
| Size | 1/2 |
| Gauge | medium |
| Supplied as | Set and single strings |
| Item number | ST-S789-SET12 |
Description
Their flexible spiral steel core produces high elasticity, quick response and a versatile tonal palette. In 4/4 the modular concept makes it easy to combine individual strings in different windings (chrome, silver, tungsten, aluminium) and tensions (Soft, Medium, Strong); a quality cellists have prized for decades.
Spirocore work equally well in orchestral, chamber and solo repertoire.
Scope of delivery
- Available as a complete set
- Single strings: A string, D string, G string, C string
Sound and physics
The construction of the string (string length, tension, cross section, material properties) keeps its overtones close to the harmonic series; the higher partials lie only fractionally above the exact multiples of the fundamental. In wound strings this is achieved by the composite design of a thin, flexible core with one or more windings of metal ribbon or wire, which puts a lot of mass on the string with little bending stiffness.
A string tuned to the same pitch on the same string length carries proportionally more mass per metre (linear mass density) when it is under higher tension.
Under the bow the travelling kink of the Helmholtz motion (the string sticks to the bow hair and slips back) stays sharp on the flexible string, and the bridge receives a sawtooth force that contains every overtone of the fundamental.
A low C string typically produces more than 40 clearly contributing harmonics.
When the fundamental of a string meets a strongly coupled body resonance, a wolf tone can appear, a note that stutters and jumps. A small weight between bridge and tailpiece on the string concerned damps and shifts this resonance; we carry wolf eliminators of 7 g and 9 g for this.
Spirocore cello strings are built on a spiral rope core of steel with chrome winding; the set is made in 4/4, 3/4, 1/2 and 1/4; light, medium and heavy are available in 4/4 only, the smaller sizes in medium. Each size is a string design of its own, matched to its string length.
The steel spiral rope core (7,800 to 8,000 kg/m³, modulus of elasticity as a measure of material stiffness 190,000 to 210,000 MPa) is built from many twisted wires and is therefore far more flexible than a single wire.
Our experience
On the 4/4 set, Spirocore is for us the icon of the full-blooded cello sound: powerful, brilliant, focused and with the metallic shimmer that many players are looking for. Add to that a long working life, with the strings settled after about a day.
When another model suits you better
If a smaller cello should sound warm and soft, we recommend Dominant, which is also made down to 1/4.
Frequently asked questions
Why are the lower strings wound?
The winding adds mass to the string without making it stiff. On the same string length a low note at similar tension needs a much higher linear mass density, and the metal of the winding supplies it.
How much does tension change when I tune higher?
From 440 Hz to 442 Hz, as many orchestras tune today, tension rises by about 0.9 per cent, and to 445 Hz by about 2.3 per cent.
What are the frequencies of the cello's open strings?
At A = 440 Hz and pure fifths they are about 65.2 Hz (C), 97.8 Hz (G), 146.7 Hz (D) and 220 Hz (A).
Where do I put the wolf eliminator?
Between bridge and tailpiece on the string where the wolf appears. Its weight shifts and damps the resonance of the system made of string, bridge and body.
How long does a Spirocore set take to settle in?
For the Spirocore spiral rope core the maker gives about one day.
In which sizes is Spirocore made for cello?
In 4/4, 3/4, 1/2 and 1/4.
These texts hold decades of experience and a great deal of heart. They are protected by copyright, C.A. Götz jr. GmbH. Please ask us before any use. Thank you for your appreciation.
