150-4C...16 ohms ,,, 150-4...32 ohms
Geez, I just realized; that was 42 years ago !!! How the time flies when you're having fun.
The original Hartsfield had an opening below where the 375 driver sat. It was through this small opening that you installed the 1540-4C. It was a knuckle-busting job. They redesigned the cabinet to accept the speaker mounted right on the back, and it had a cover that slightly resembled a coffin, hence the name.
If you can take off the back and see the speaker, it's a newer Hartsfield; if you can't figure out where the hell the woofer is, it's an older Hartsfield.
Being a newbie on JBL speakers, I am only familiar with the Casitas address. Unfortunately I disposed off my only JBL brochure that had the Casitas address. All of my subsequent brochures have the current address of today.
So the Hartsfields had mostly 150-4C's and a few LE15s, and most of the Paragons had LE15s, and a few 150-4C's.
Looking at the patent I get the impression that the primary horn layout gave the possibility to build a backloaded or a frontloaded horn.
The second layout is only useful for a frontloaded horn. And I do suppose that it has advantages in frequency response. This means lesser irregularities and perhaps a higher upper frequency limit (which is most offen a problem with bass horns.)
___________
Peter
Hallo Peter,
yes correctly , in the catalog of 1954 there is the Hartsfield as 208-DH kits with the D208 Fullrange driver as backloadet Horn.
regards
juergen
from the Hartsfield article on this site:
http://www.audioheritage.org/html/pr...hartsfield.htm
"The logic of stuffing a $25 driver into a $300 enclosure was questionable at best and was never a marketing success. This option was dropped within two years. "
© 2000 Don McRitchie
But I wonder if that D208 option might have been influenced by the Lowther loudspeaker single-driver philosophy and designs that were popular with hobbyists in England. The D208 would have been the LE8T of it's time, and there are still plenty who still think the LE8T is the best option available.
Around the same time the Hartsfield was introduced Lowthers were being used in large rear-loaded folded horn cabinets. The TP1 London enclosure, introduced in the 50's and still being made, is a big front and rear-loaded corner horn, but at 39x31x23 inches (102x80x60 cm) not quite as big as a Hartsfield.
Maybe someone at JBL thought the D208/D216 was special enough to spark a wave of interest similar to the Lowther popularity that is still going strong today.
Has anyone ever heard a D208/D216 in a Hartsfield cabinet?
Lowther TP1 picture attached
glen
"Make it sound like dinosaurs eating cars"
- Nick Lowe, while producing Elvis Costello
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