Quote Originally Posted by Mustang Marvin View Post

Since I have a pair of 511B's I was wondering if anyone had adapted the large format drivers like the 399 to the smaller throat 511. I don't want to loose sonic performance.

The two are mutually exclusive

Old Community horns can be found cheap. The radials aren't bad.

If you have to do anything go 2 inch and adapt up.

On a really short budget:

Parts-Express.com:Pyle Pro PH916 1.4" Bolt-on Constant Directivity Horn | Pyle PH916 Bolt-On horn bolt on horn 1" horn constant directivity horn

I use to know what these were cloned from, but the old grey matter ain't what the used to be. I think maybe Beyma

They work, and go well to about 800

Ignore Pyle specs, they just buy them from China

Those are "usable", I may be under rating them but to me that is preferable to over rating.