Thank you POS for message.
I know that JBL 3678 use the same 2342 horn.
About 2342 horn very few things can be found on internet.
Unfortunately I am from Romania and a market of used speakers does not really exist.
About JBL speakers - no way. Dreams.
If i need something I try to buy from internet, but to buy from outside
European Union, shipping & taxes became very very expensive, most of time taxes more expensive as items.
A friend of mine can build this horn if I give him a model or all dimensions.
If somebody can help me with dimensions will be perfect.

Thank you once again
Keep on touch,