Rauna of Sweden can now (as of March 2017) offer its customers a factory upgrade for the entire Rauna and Opus 3 speaker series. With this upgrade, your vintage Rauna or Opus 3 speakers will be fitted with updated crossover section and new drivers. The company has also developed a new damping material which it claims will eliminate the final concrete speaker cabinet colouration. This new damping material is said to result in improved dynamics, a better three-dimensional sound stage, better mid-range and, above all, a higher resolution at all levels.
With this factory upgrade, it is reassuring to hear from Rauna of Sweden that the natural and uncoloured sound characteristics, which has always been a hallmark for these speakers, has been fully maintained.
The Rauna speaker series
1. Rauna Leira
For the Rauna Leira speakers, the company offers two upgrade kits. Upgrade kit 1 consists of 2 x 6,5 inch coated paper bass driver units, 2 fabric treble soft domes and 2 crossovers. This upgrade costs SEK 5000.
Upgrade kit 2 is the same as upgrade kit 1, but with the drivers/cones mounted on an MDF baffle, all nicely covered under a black speaker grill cloth. Price for this upgrade is SEK 6500.
Specifications for either of these upgrade kits:
Sensitivity: 87dB
Impedance: 8 ohms
Frequency response: 40-20,000 Hz
2. Rauna Njord
For the Rauna Njord speakers, the company offers the Njord kit v2. This kit consists of 4 x 6,5 inch coated paper bass/mid-range driver units, 2 fabric treble soft domes and 2 crossovers. The drivers/cones are further mounted on a baffle, all nicely covered under a black speaker grill cloth. Price for this upgrade is SEK 9500.
3. Rauna Ymer
The Rauna Ymer model can be upgraded with the Ymer kit v2. This upgrade kit includes 4 x 6,5 inch coated paper bass/mid-range driver units, 2 fabric treble soft domes and 2 crossovers. Like before, the treble is placed between the bass driver units. The new driver units and crossovers are, however, a vast improvement. Price for this upgrade is SEK 7500.
Specifications for this upgrade kit:
Sensitivity: 91dB
Impedance: 4 ohms
Frequency response: 35-20,000 Hz
The Opus 3 speaker series
1. Opus 3 Chorus/Credo
Opus 3 Chorus/Credo can be upgraded with the Chorus upgrade kit, which is composed of 2 x 6,5 inch coated paper bass driver units, 2 fabric treble soft domes and 2 crossovers. This upgrade costs SEK 5000.
Specifications for this upgrade kit:
Sensitivity: 87dB
Impedance: 8 ohms
Frequency response: 45-20,000 Hz
2. Opus 3 Chaconne/Crescendo
Rauna of Sweden offers two upgrade kits for the Chaconne/Crescendo speakers – Chaconne/Crescendo kit respectively Chaconne/Crescendo kit Deluxe.
The Chaconne/Crescendo upgrade kit consists of 2 x 8 inch coated paper bass driver units, 2 fabric treble soft domes and 2 newly developped crossovers. This upgrade costs SEK 6000.
Specifications for this upgrade kit:
Sensitivity: 89dB
Impedance: 8 ohms
Frequency response: 30-20,000 Hz
Crossover frequency: 2100 Hz (12/18 dB crossover)
Continuous effect: 100 W
Drivers: 220 mm coated paper bass cone and 27 mm fabric treble cone
The drivers in the Chaconne/Crescendo kit Deluxe are from the SEAS Excel reference series and are mounted on a special baffle. Price for this upgrade is SEK 14900.
Specifications for this upgrade kit:
Sensitivity: 89dB
Impedance: 8 ohms
Frequency response: 30-20,000 Hz
Crossover frequency: 1800 Hz (12/18 dB crossover)
Continuous effect: 120 W
Drivers: SEAS Excel 220 mm nextel coated paper bass cone and SEAS Excel 35 mm fabric treble cone
Rauna of Sweden also offers various foam treatments (e.g. Anjala foam and Rauna Tyr foam). For further information and specifications, please refer to the official company website linked below:
http://rauna.mamutweb.com/Shop/List/Rauna/10/1
vintagehifiproducts 
Does the upgrade kit for Ymer fit Balder too?