My goal in building a double top guitar is to create an instrument that emphasizes the advantages such as volume and projection and at the same time minimizes the disadvantages of less tonecolour and nasality.
During the development of my double top guitar I had active support from Gernot Wagner. He was at my side with extensive advice and explained the exact structure of his guitars. Together with Matthias Damman, they can be seen as the fathers of sandwich construction.
With this method, the top is made of three parts that are glued together. Inside and outside, the top consists of very thin layers of tonewood (spruce or cedar). In between we have a honeycomb structure made of aramid fiber (Nomex). With this method you can achieve a lighter top compared to a solid top, but with the same rigidity.
With this construction method I achieve an advantage of weight up to 25% compared to a solid top. This benefit is one reason, but not the only reason, that improved the volume of my double top guitars. Another reason for the increased volume we can find in my own developed laminated rib constrction. In this case the ribs are no longer bent over the bending iron, like on the traditional way. I am using several thin layers of fine tonewood veneer, getting glued together by pressing them into a jig, that got the shape of the guitar ribs . This creates a very stiff construction and supports the Double Top prfect. The result is a strong, straight forward-looking sound development.
However, some double top guitars are not louder than a traditionally built guitar. In my opinion the reason for this is a too heavy top construction. If the double top is heavier than a solid top, the advantage is gone.
The lower weight not only improves the volume. It makes playability more comfortable and also improves responsivness. The guitar reacts more directly and agile to the player’s attack, especially while changing from a nail attack to more ‘meat’. The light weight of the Double Top also generates more high overtones, especially closer to the bridge. This creates a very beautiful ‘Echo Effect’ on my guitars, which makes the sound full and crsipy.
The big disadvantage of many double top guitars is the limited range of timbre. These guitars don’t show much differences in sound colour (dark / bright) while playing through the different striking areas between the sound hole and bridge.
That’s the point that I have tried to pay special attention to. To reduce these disadvantages, my double tops are worked out specially, making certain areas of the top more flexible. My experience help me to work out these individual areas of the top properly, getting a wider range of timbres. Some of my customers were amazed at the variety of sound colours. They wouldn’t have guessed they were playing a double top guitar if they hadn’t known.
The saddle bone on the head as well as the bridgebone are produced with a certain technique, that allows me to improve the intonation of the guitar. In this way I can control the compensation of each string individually, resulting in a more precise tuned guitar by the player. This leads to a noticeably cleaner and better intonated sound experience.
For my finish, I am only using shellac for the entire instrument. Layer by layer, the shellac is applied in the traditional process (French Polish) by hand. Shellac has significant advantages over other varnishes. It leaves only a very thin, protective layer on the guitar due to the method of application, which allows a wider range of vibration for the top. In this way the instruments gains more volume and sonority compared to artificial lacquers. Shellac also has the advantage that it is reversible and very easy to maintain.