It can be observed that a transient reed, i.e. the part that produces a tone when air flows into the slot of the reedplate, has a slightly different tuning in the free field (i.e. in the uninstalled state) than in the installed state in the instrument.
This is due to the fact that in the instrument the surrounding volume of the bellows forms resonances, which, however, also change constantly depending on the expansion of the bellows. These resonances have a feedback effect on the vibrating reed, which changes the pitch slightly.
The sound of the reedplate on a reed block and in the installed state is also perceptibly different from that of a reedplate in the free field (i.e. in a holder for single reedplates or waxed on a reed block positioned directly over a blowhole in the working plate). This is how only the pre-tuning is performed.
Therefore, the final tuning of an instrument is done in such a way that the reed block is measured installed in the instrument body. However, subsequent retuning requires the repeated removal and installation of the reed block in order to manipulate the reeds.
AKKOflip can do the pre-tuning and the final tuning in a very comfortable way together. The volume of the instrument's body and bellows is simulated by a 110 mm
high frame with a sealed top plate, which has an audible effect on the measured pitch and sound. In addition, a cassotto can be activated, which simulates e.g. the space on the bass side between the filling and the finger plate, or the treble cassotto on an accordion.
As on an accordion or harmonica, the reed blocks are to be mounted inside the resonance chamber under the cover plate. To access the reed blocks/reedplates/reeds, this cover plate, which is guided in two hinges at the front, is simply flipped open from the back to the front. Hence the name AKKOflip.
After opening, the parts to be tuned are easily accessible directly in front of you, and you can perform the pre-tuning and even the final tuning.
The system consists of a base frame and exchangeable cover plates for various applications:
- Standard version for different reed blocks
- Version for production for serial production of same reed blocks
- Single reed plate version for tuning of single reed plates
- Tremolo version for tuning single reed plates in tremolo configuration
- Helikon version for tuning Helicon reed plates