Smallest Footprint Horn and Driver that can reach 500 Hz

[hornwannabe]

 

[Pano]

The Faital Pro LTH142 is 350mm x 240mm and is probably one of the most compact horns that will reach 500Hz when used with the SB65WBAC25-4 driver.

The SB65WBAC25-4 os a very low efficiency driver. Understandable given its size and bandwidth. Does the horn help it any?