I have been scouring the internet for published horn system plans for myself, the one that seems intriguing is Kimmo Saunisto's KS-1804 mk2. The cardioid concept is interesting. The issue being the Stereolab horns that were used in the original design aren't available anymore. Could someone suggest what can be used as a direct replacement?
@motokok: There were a lot of very interesting designs and some really useful objective and subjective interpretations for many designs.. Whatever is available in the web archive can be found here
https://web.archive.org/web/20170503151514/http://kimmosaunisto.net/index.html
https://web.archive.org/web/20170503151514/http://kimmosaunisto.net/index.html