JBL HLA 4895 upgrade tweeter

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Bassda

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Joined 2020
Hello,

my name is Alex and i have this vintage speaker hobby.

i own severals JBL HLA systems with the oldschool 2451SL aquaplased 4inch coil 1,5inch exit tweeter. very nice-

As a standard this long throw 40x20 horn is used above 1140Hz in the setup.

Currently i want to test and upgrade the tweeter section to a more modern
soluting with less "ringing" distortion at high power levels.

Maybee somebody else did an effective upgrade to similar units.

i consider the following:

  • 4inch truextent recone. easy but expensive and still 4inch
  • JBL 2435 3" i dont know the SPL capabilities and seems they have consistency issues in production
  • DCX 464, passive crossover, that seems little overkill when lowest frequencies might be 900Hz
  • BMS coaxial , passive crossover seems they have issues with THD aswell on high power usage especially in the upper midrange
  • anything else that would cover this range "better" less "ringing" then the 2451?

Any feedback is highly appreciated. Many thanks for this forum.
if you need any Details on HLA setups, speakers and parts i am happy to help.
 
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Bassda

Member
Joined 2020
Hello,

this Question here relates for PA usage outdoors.
aswell i am happy to hear for any home advice as i have a separate listening room with 2 HLA , Rt60 is around 0,5seconds for whole band with absorbers and diffusors.
I have xilica 4080 DSP for the PA system.
currently i have Umik and REW to help me.
Arta or SoundLive would be an option if needed.
 
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URI55

Member
Joined 2019
Since I mixed two times on HLA, I agree: HF is not the strong part of the box.


Many years ago we compared ND1460, DE800 and CP755ND.
Back then 755ND sounded best to us, but we went for 1460, because it was way cheaper and came out second.
Nowadays I also own 462 and DE990, quite a step up from 1460.


BTW 1.4" is more like 36mm not 34mm.
Anyone with CNC should be able to make adapter rings for you, if you can decide for a slope
 
chris661

chris661

Member
Joined 2008
URI55 said:
Many years ago we compared ND1460, DE800 and CP755ND.
Back then 755ND sounded best to us, but we went for 1460, because it was way cheaper and came out second.
Nowadays I also own 462 and DE990, quite a step up from 1460.
Click to expand...

I'm curious about this comparison, mostly because the ND1460s I have here measure well and sound great once properly processed.

Did you measure and EQ each HF driver to replicate how they'd be used?

Chris
 
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URI55

Member
Joined 2019
kipman725 said:
is an adapter needed between 1.4" and 1.5"? the step at the throat would only be 1.27mm on each side, one wavelength at 20kHz is 17.2mm so the discontinuity is <lambda/10.
Click to expand...


I have replaced DE700 ( 1.5" ) with DE920 ( 1.4" ) without any adapter and thought, it worked pretty well.
But speaker design is also about paying attention to small details, so if this would have been a permanent solution, I would have used an adapter.
 
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URI55

Member
Joined 2019
chris661 said:
I'm curious about this comparison, mostly because the ND1460s I have here measure well and sound great once properly processed.

Did you measure and EQ each HF driver to replicate how they'd be used?

Chris
Click to expand...


Regarding the 755/800/1460 comparison:
I can`t remember on the accuracy, it`s been a while, but there was DSP involved for sure.

Last year I did compare 4015NSD and DE920 on the same horn, FR matched to less than 0.5dB below 12k ( 1/12 octave smoothing )
The drivers sounded very, very different.

Regarding the 1460/990/462 comparison:
Despite Covid I actually didn`t have time to do it on the same horn, but I`m pretty confident about the outcome.

As soon as I have finished my project of implementing the 462 in a hornloaded application, I will catch up on this comparison.
 
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