woofer impedance folded horns

[Esoteric]

[QUOTE=Harvey Gerst;181390]

We were making very few Hartsfields by the time the LE-15 came out, but yes, I think I recall putting the LE-15 in some of the last Hartsfields made. I may be wrong, but catalogs from that period (around 1965) should have it right.

Sorry Harvey. When Hal Cox suggested a 4 ohm woofer for me we were discussing the similarity between my horns and the Hartsfield and I thought that the 150-4-C was 4 ohms. What was the impedance?

Nick

[Maron Horonzakz]

150-4C...16 ohms ,,, 150-4...32 ohms

[Esoteric]

150-4C...16 ohms ,,, 150-4...32 ohms

Thank you, Maron. I guess I'll stick with 16 ohm woofers. Nick

[Harvey Gerst]

Geez, I just realized; that was 42 years ago !!! How the time flies when you're having fun.

[rs237]

[quote=Harvey Gerst;181390]

We were making very few Hartsfields by the time the LE-15 came out, but yes, I think I recall putting the LE-15 in some of the last Hartsfields made. I may be wrong, but catalogs from that period (around 1965) should have it right.

Harvey,

thanks for your answer. I will test the LE15 and the E145 in my Hartsfield project. I hope to find also still a pair 150C(-4).

regards
juergen

[Harvey Gerst]

Harvey,

thanks for your answer. I will test the LE15 and the E145 in my Hartsfield project. I hope to find also still a pair 150C(-4).

regards
juergen

Keep in mind that this only applies to the "coffin-backed" Hartsfields. We never tried an LE15 in the original Hartsfield.

[rs237]

Keep in mind that this only applies to the "coffin-backed" Hartsfields. We never tried an LE15 in the original Hartsfield.

Harvey,

Yes I build the “coffin-backeed” Hartsfields. From the original one there are unfortunately no plans, or has you which ?

regards

juergen

[Harvey Gerst]

Harvey,

Yes I build the “coffin-backeed” Hartsfields. From the original one there are unfortunately no plans, or has you which ?

regards

juergen

Vern Bender built most of the original Hartsfields, and he kept a set of the plans at home. I don't even know if he's still alive.

[Esoteric]

Harvey,

Yes I build the “coffin-backeed” Hartsfields. From the original one there are unfortunately no plans, or has you which ?

regards

juergen

Harvey, what is the "coffin "back"?

Nick

[Harvey Gerst]

Harvey, what is the "coffin "back"?

Nick

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.

[RKLee]

When we started putting out Hartsfields and Paragons, they came standard with 150-4C's in both. Even with the first "coffin-back" Hartsfields, they had 150-4C's. After Ed May and Bart Locanthi came up with the LE-15, we switched to those instead.

Most of the Hartsfields were made during the Fletcher Drive years. The coffin-back Hartsfield was designed by Bill Burton and Bart Locanthi while we were still on Fletcher Drive. We started thinking about stereo only during the last year or so at Fletcher Drive, but it became more serious when we moved to Casitas.

The Paragons were all from the Casitas years. Ed May didn't come on board till after we moved to Casitas, so no LE-15's were even designed until well after our move from Fletcher Drive. I remember working on the first Paragon prototype. That's the only time I met Col. Richard Ranger.

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.

[glen]

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.

if you can't figure out where the hell the woofer is, it's an older Hartsfield.

Here's a picture of the original Hartsfield setup from the patent application (on this site) showing where the woofer sits, and also a nice drawing of the horn path.

[Hoerninger]

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

[rs237]

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

[glen]

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