Hebrew Hammer
10+ year member
CarAudio.com Elite
Mark Eldrigde did it...but I also believe he had >1yr into rebuilding his entire dash, and had custom horn bodies as you mentioned.
Don't put horns on top of your dash. First issue, the pathlengths/imaging, etc. As stated, the dash itself acts as an extension of the horn body when mounted under the dash. And car audio horns have a lot of vertical dispersion. Second issue, the harshness of the horns when on-axis. Third issue...they would have too much output when on axis.
Yes Mark did it..with a certain amount of success...but spent many years trying to perfect it...it was nice but not perfect.....the best it ever sounded IMO was at finals in 2004, but it didn't have horns in it...and having a center channel always helps //content.invisioncic.com/y282845/emoticons/naughty.gif.94359f346c0f1259df8038d60b41863e.gif