Crossover help for JBL LE14A, LE20, LE5-2

[redglobe]

I reviewed Troels Gravesen's website for the JBL100/4310 rebuild. it seems like I can use his cross over for LE20 and the LE5-2. However, I have a JBL LE14A woofer rather than the JBL 123A.

Below is Troels' schematic for the 4310. Can someone tell me how to alter the crossover for the 123A to suit the LE14A?

 

[Jeffery]

Looks like you could use the bottom 2/3rds of the L220 network for the LE14A/LE5 - or at least the LE14A part. The tricky thing about moshing crossovers together is whether or not the various parts might crossover at the right spot/slope or interact with each other correctly.

No idea if this will work or not, but I see you are anxious to get something going, so here's at least a place to start.

If this isn't what you want, just reply in this thread - no need to start another.

 

[R Swerdlow]

You might also adapt portions of Dennis Murphy's revised JBL L100A crossover:

 

[redglobe]

Thank you for the replies. Can either of you give me an idea at what frequency they are rolling off the LE14A?

 

[Jeffery]

Thank you for the replies. Can either of you give me an idea at what frequency they are rolling off the LE14A?

According to the spec sheet in post #2, the crossover frequencies are 800Hz and 5000Hz.

 

[R Swerdlow]

The crossover frequencies in the Dennis Murphy L100A are:

950 Hz – 123A woofer to LE5-2 mid range
5000 Hz – LE5-2 mid range to LE25 tweeter​

All crossover slopes are Linkwitz-Riley 4th order. The woofer-mid crossover frequency of 950 Hz was chosen because the mid driver wasn't smooth at lower frequencies. The woofer would perform a bit better off-axis at a lower frequency, but the mid range just couldn't cut it.

For more details, see http://forums.audioholics.com/forums/threads/the-vintage-jbl-west-coast-sound-becomes-the….25014/

 

[Zonker92]

I like the idea of using the L220 or L222 crossover; the LE5 midrange driver is quite similar to the one from the L100. As I recall, one alternative load of the L45 Flair also uses the driver complement you are using, although its design is earlier and probably less refined than the L220/222.

 

[redglobe]

Hi Guys, thank you for all your input. In the end, do you think I would have a high quality speaker or would this just be a good sounding one? Presently, I have an Orco-designed TMM with Focal W7441 7" mids and Audiom TLR tweeters (Zalytron used to sell these designs. Though I upgraded the caps to Jantzen Superior Z). They reproduce the music very well. However, I have such a large room and high ceiling that some of the bass gets lost.

 

[Zonker92]

IMHO they could be very good; those are all nice drivers. Great woofers. What are the cabinets like? I put some LE14As in some old Viscount cabinets and they have terrific bass:

http://audiokarma.org/forums/index.php?threads/c36-viscount-le14a-ewaves.428160/

 

[redglobe]

Hi Zonder92, Thank you for the reply and the link. I would be the speakers in a ported enclosure to fit within the recommended cabinet recommendations. On your thread someone recommended 3 cubic feet.

By the way, your retrofitting of the LE14A look very good. You did not include a mid range. Do you have a dip in the mids? Have you ever heard Focal in the Electra or Utopia line? Would the JBLs, with the upgraded crossovers be competitive in sound reproduction?

 

[EarlK]

Hi Zonder92, Thank you for the reply and the link. I would be the speakers in a ported enclosure to fit within the recommended cabinet recommendations. On your thread someone recommended 3 cubic feet.

By the way, your retrofitting of the LE14A look very good. You did not include a mid range. Do you have a dip in the mids? Have you ever heard Focal in the Electra or Utopia line? Would the JBLs, with the upgraded crossovers be competitive in sound reproduction?

The Focal components you have are really quite good.

You could combine them with the le14a to make a high-efficiency 3-Way ( at @ 92db ).

I'd go MTM over the le14.

If you were on the same continent as Troels G, you'd have a chance of getting him interested in such a project ( of course he'd need all the drivers for this sort of work ). I suspect that he'd like to do a design with the le14a ( just add to his own knowledge base ).

Since that scenario is unlikely to unfold, you might see if you can employ Dennis Murphy to design a custom network for your stuff ( he will also need the drivers > but at least he's US based ).

Contact him through MurphyBlaser Productions if you get interested in that approach.

Good Luck