This King 4BF Sonorous trombone is an outstanding example from the early 1970s, preserved in super mint condition. Few instruments of this era remain as clean and original as this one, making it a valuable historical reference for players and collectors alike.
The 4BF features the same core design as the popular King 4B, but with the addition of the F-attachment rotor system, offering extended range and added versatility. This example retained its original lacquer, with a bell and handslide that show no signs of damage or repair. The handslide is remarkably straight and smooth, providing excellent playability, while the bell maintains the warm, projecting sound that King instruments of this period are celebrated for.
For many advancing players, the 4BF made an ideal first trigger trombone: approachable, dependable, and versatile enough for symphonic, band, and church repertoire. Jazz players moving up from a King 2B or 3B often chose the 4BF as a way to add a large bore tenor to their arsenal without losing the familiar King feel and sound.
The instrument originally included its King case, and a mouthpiece was not provided. In-hand, it played exactly as expected from a Sonorous model of this era — broad tone, reliable intonation, and a balance that made it a long-time favorite in both professional and educational circles.
Today, examples of the early 1970s King 4BF Sonorous in this level of condition are very rare. This instrument has since been sold, but remains documented here as part of our Archive of Sold Instruments for historical and reference purposes.
Questions 🎵
Q: What does the “Sonorous” name signify on a King 4BF?
“Sonorous” was used by King to market this line of large bore tenor trombones, emphasizing their broad, resonant tonal qualities.
Q: Who typically played the King 4BF?
The 4BF was popular with advancing students, working professionals, and jazz players needing a dependable large bore with F-attachment. Its versatility made it a go-to instrument in the 1970s.
Q: Why are early 1970s examples sought after?
King’s manufacturing during this period is considered a golden era for consistency and craftsmanship. Instruments like this one showcase the company’s balance of durability, playability, and tonal richness.
This King 4BF Sonorous Trombone (early 1970s) has been sold and is now archived for historical reference. Looking for a similar instrument? Browse our available trombones 🔎.
