Great site! I just discovered it today.
I have two guitars by Georg Bolin. My first was a standard 6-string which I bought in 1975. Back then Bolin got an order from Andrés Segovia, and he made several guitars for Segovia to pick from. Mine is one of the guitars he built on that occasion.
I bought my alto guitar in 1981. Then I visited Bolin in his studio in Stockholm. That was a very interesting meeting. He showed me several of his guitars and inventions, and explained his philosophy of guitar building.
One of Bolin's inspirations was the famous Swedish tenor Jussi Bjørling. He told me that he had observed Bjørling in a concert hall, first from very close, and he was surprised that Bjørlings voice sounded so weak, that is without much volume. But then he listened to Bjørling from the back of the concert hall, and he could still hear Bjørlings voice very clearly. So the voice carried very well without having much volume. This inspired Bolin to try out a new kind of guitar that was much smaller than standard C20 classical guitars - it looked more like a Sor guitar. Like Bjørlings voice this would carry the sound very well without having much volume. He also had a guitar that he called a ters guitar. I think it was a 6 string tuned up a third.
I think that many of Bolin's guitars doesn't sound as loud as most Spanish guitars, but they have a very long sustain. That makes them very suitable to polyphonic music, like baroque or renaissance music.
Bolin had also invented his "tonbord" - or "sound board". This was a kind of amplification system for classical guitars that reproduced the guitar sound by a wooden cabinet. I have heard this on a few occasions on concerts for guitar and orchestra. But he had also expanded this idea to a "tone wall", which was a much bigger system. The idea here was to amplify a small orchestra, like a theatre orchestra. The "sound wall" would make them sound like a much bigger orchestra.
I have uploaded a picture of Bolin on the gallery from when I picked up my alto guitar. The "sound wall" can be seen behind us.