Spirocore S37 Bass D String: Medium

The Spirocore S37 Bass D String: Medium is a premium replacement string for double bass players who want fast response, strong projection, and the long-lasting performance that has made Spirocore a standard choice for generations. As part of Thomastik-Infeld's Spirocore Orchestra bass line, the S37 is the medium D string for 4/4 bass and is built around the brand's signature spiral core design for a lively, flexible feel under the bow and the hand.

This string is a strong option for advancing students, committed amateur bassists, and professional players who need one dependable D string for orchestral repertoire, section work, and more varied playing styles. The chrome outer winding and spiral core construction support the focused, responsive character players expect from Spirocore, while the crimp ball end setup makes it practical for standard bass tailpiece installation.

Features & Specifications

• Instrument Fit: Designed for 4/4 double bass.
• String: D string, listed as Re II.
• Tension: Medium tension.
• Manufacturer Model: Thomastik-Infeld S37.
• Core Material: Spiralcore construction.
• Winding Material: Chrome outer material.
• Ball Material: Aluminum ball.
• Tailpiece End: Crimp ball end.
• Tension Value: 32 kg / 70.55 lb.
• Line: Part of the Spirocore Orchestra double bass series.
• Use Case: Well suited to players seeking a premium orchestral bass string with a responsive, durable feel. This is an inference based on the published construction and line positioning.
• Manufacture: Thomastik-Infeld states its strings are handmade in Vienna.