Here's a 1" three-bolt JBL driver (275) attached to a JBL horn (H5040), for reference/comparison (& FWIW).
DSC_6121a by Mark Hardy, on Flickr
... and here's the same, compared to a 2" throat, four-bolt JBL 2441 driver (sans horn).
DSC_0455 (3) by Mark Hardy, on Flickr