The Siren Board

or could they be diaphone or other horns?

There are many acoustical devices that make use of either linear, exponential, or other shaped horns...everything ranging from sirens, to fog horns, to audio speakers.

Adam Pollak wrote:There are many acoustical devices that make use of either linear, exponential, or other shaped horns...everything ranging from sirens, to fog horns, to audio speakers.

according to the design principles of thunderbolt series, is the exponential shaped horn the best for amplifying and resonanting output sound?

It could be anything, but it's unfortunate that we don't have a larger picture.

is it still in use? a recording of that would be cool