Jump to content

2 way hartsfield jbl How good is the low end


bracurrie

Recommended Posts

On 9/27/2015 at 1:05 AM, garyrc said:

 

What vintage Hartsfield did you have?  Did it use the 154C woofer, or a LE15 (LE15A?), or some other?  Did they add the 075 in later years?  I heard they did, but I never had that confirmed.  Did you happen to use it with a JBL Energizer with frequency response and damping individualizing?  How did it sound?

A lot has happened since I posted this thread. My mother passed away in Memphis summer of 2016 and I got to hear the Hartsfield speakers. They were positioned in the corners of the room and had pretty good bass. I brought a jazz album I knew well to play and the mids were very pleasing to my ear.
In any case the speakers are not a matched set. One is a '53 and one is a '57 but they appear identical with same crossovers and drivers.  Now I have to decide whether to go down that rabbit hole of buying them as they are just now available.

Brad

JBL Hartsfield bass driver.jpg

JBL Hartsfield crossover.jpg

Link to comment
Share on other sites

Their resale value will probably continue to climb with time.  I'd consider them to be investments at least. 

 

I've never seen acoustic measurements of Hartsfields, but I'd think that they are very much like ported La Scalas in terms of low end frequency response, and like 2-way JubScalas in terms of their higher end performance.  Probably need to check their passive crossovers for capacitor series resistance and replace if necessary, then check the drivers, especially the compression driver diaphragms. 

 

An excerpt from the Audio Heritage web site on the Hartsfield:

 

Quote

In 1964, the driver configuration was changed to add the 075 ring radiator to make a three-way system. This addressed a long standing limitation of the Hartsfield -- a restricted high frequency bandwidth. The 375 driver never did extend much beyond 10Khz. In the 1950's, this was not that significant since most recordings were also restricted in high end response. However, by the 1960's it was common for recordings to contain information that reached into the highest octaves. The new 085 configuration, consisting of the 150-4C bass driver, 375 midrange, 537-509 horn, 075 tweeter, N400(or N500H) and N7000 cross-overs, could now boast a bandwidth that would extend beyond the limits of human hearing.

Unfortunately, 1964 was also the last year of production for the Hartsfield. Its discontinuance was related to the success of stereo reproduction. The requirement for a corner placement was not a significant issue when only one speaker had to be located in a monaural system. However, a stereo system required two, unobstructed, adjacent corners that were reasonably spaced. Not every home could accommodate this requirement and thus the available market was restricted.

 

Looks like you'll eventually be in the market for a full-range compression driver...such as the dual-diaphragm BMS 4592-ND...that could give you back the 10-20 kHz octave if you decide to listen to them on a regular basis.

 

I'd hang on to those old 375 drivers though for their nostalgic resale value. 

 

Chris

Link to comment
Share on other sites

21 hours ago, bracurrie said:

A lot has happened since I posted this thread. My mother passed away in Memphis summer of 2016 and I got to hear the Hartsfield speakers. They were positioned in the corners of the room and had pretty good bass. I brought a jazz album I knew well to play and the mids were very pleasing to my ear.
In any case the speakers are not a matched set. One is a '53 and one is a '57 but they appear identical with same crossovers and drivers.  Now I have to decide whether to go down that rabbit hole of buying them as they are just now available.

Brad

JBL Hartsfield bass driver.jpg

JBL Hartsfield crossover.jpg

 

Brad,

 

Sorry to hear about your mother.  

 

My guess is that the one pictured is a two way, rather than a three way;  I would think the three way would have one extra crossover, probably the N7000 (if I remember the designation correctly of the one used to accommodate the 075 in the Paragon, bringing it in at 7K).

 

In the intervening time since your last post, I've seen a sweep on the 375, but I don't know with what horn.  It showed a very small peak at 6K to 8K, flat at 9K, - 5 dB at 10K, - 15 dB at about 12K.  I'm sure it sounded great, though -- just needs something above.

Link to comment
Share on other sites

  • 3 weeks later...
  • 1 year later...

@Chris A The crossover from my JBL hartsfield was taken to an audio repair shop as I thought it could use new capacitor as old as it was. The tech wasn’t able to get into the crossover itself with being sealed. The measurements taken indicated all was good in spite of one pin being out and non repairable, something about difficulties soldering it to plastic. If I wanted a second opinion where would you suggest? I suppose it sounds good, but I’ve never known any difference. Thanks for any advice you can offer..

Link to comment
Share on other sites

The crossover schematic looks as if it's a first order crossover at ~500 Hz, which means that it won't be terribly susceptible to cap aging (i.e., high ESR).  You could construct another crossover in order to bypass the equivalent series resistance of the caps inside the old networks (8 and 13 µF in parallel--for a total of 21 µF), which will attenuate the HF driver relative to the woofer:

 

jbl_d-30085_hartsfield_crossover_500hz_1

 

If I were in your shoes, I'd invest in a calibrated microphone (such as a UMIK-1) and use something like REW to measure the frequency and phase response of the loudspeakers as-is.  Then it will be much easier to decide if you've got an issue with the old crossovers.  The USB microphone will serve you from then on in setting up your loudspeakers to get the best performance out of them.  Also, with the above schematic, you could get someone like Bob Crites to make you some replacements, and you can hang on to the original crossovers for nostalgia's sake, but use new ones.

 

Chris

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...