Cello Bertram Brenig Opus 4 from 2026 (‘Clara’).

Description: Whenever the weather permits, I move my workshop outside and work in nature, where the wood is in its natural environment. The top of Opus 4 was made from mountain spruce tonewood that had been stored for about 20 years. It has a density of 0.4 g/cm³ (8% FG) and relatively wide but regular growth rings. There is a visually interesting, narrow growth defect on the upper right edge, which was probably caused by a branch. The ribs and back are made of very even and beautifully flamed sycamore maple. With Op. 4, I wanted to build a very unique cello that would not be based on conventional dimensions. It was to be more voluminous and powerful, perfect for professional cellists looking for a special challenge. The oil varnish with intense red-brown pigments gives Op. 4 a warm, historical-looking sheen.

    

Body length (back): 770 mm

Upper bout width: 370 mm

Width of the C-bout: 250 mm

Lower bout width: 460 mm

Fingerboard length: 580 mm

Fingerboard: Ebony (round)

String length (vibrating): 695 mm

Bridge: Belgian model (Despiau®)

Pegs: Wittner® fine tuning pegs

Tailpiece: Plastic (Wittner®)

Strings: Larsen Il Canone (medium)

Spike: Carbon

Total weight: 3230 g

Op. 4 was completed in late December 2025. Op. 4 has a warm and very intense sound. The lower registers have an amazing strength and projection.

Model: Own model Dedication: Psalm 150:3-5

Making of op. 4

Construction and modal analysis of op. 4